基于springboot + vue 的个人博客搭建过程

前言

码神之路网站所使用的博客，项目简单，需求明确，容易上手，非常适合作为练手几项目。
成品预览: blog.mszlu.com
项目搭建思路：
1. 提供前端工程，只需要实现后端接口即可
2. 项目以单体架构入手，先快速开发，不考虑项目优化，降低开发负担
3. 开发完成后，开始优化项目，提升编程思维能力（页面静态化，缓存，云存储，日志等等…）
4. docker部署上线
5. 云服务器购买，域名购买，域名备案等…

项目使用技术：springboot + mybatisplus + redis + mysql

工程搭建 1. 前端工程

用vscode打开，然后编译启动，具体命令如下：

npm install
npm run build
npm run dev

BUT，我们在这里不用这种方式，而是采用另外一种方式去启动前端。
下面给出具体命令：

yarn
yarn start

看在这里，我们可能会有一个大写的问号：npm和yarn有什么区别呢？

npm和yarn的区别请点这里

总的来说就是，yarn更快，更简洁（真是忘金油式的回答啊！）
总结一下为什么yarn比npm更好吧：

1. 速度快： 采用并行安装和离线安装（如果之前安装过yarn，安装时就可以从缓存中离线安装）
2. 安装版本统一： （确保每次拉取项目使用的依赖版本都是相同的）
3. 更简洁的输出
4. 多注册来源处理
5. 更好的语义化（命令更简洁）

2. 新建maven工程（父框架） 2.1 新建blog-parent父框架， 删掉src，pom.xml引入依赖

    4.0.0

    com.raxcl
    blog-parent
    1.0-SNAPSHOT
    
        blog-api
    
    pom
    
        org.springframework.boot
        spring-boot-starter-parent
        2.5.0
        
    

    
        8
        8
    
    
        
            
                com.alibaba
                fastjson
                1.2.76
            

            
                commons-collections
                commons-collections
                3.2.2
            

            
                com.baomidou
                mybatis-plus-boot-starter
                3.4.3
            
            
            
                joda-time
                joda-time
                2.10.10
            
        
    

    
    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    

2.2 maven依赖飘红问题

过程中可能会有一些依赖飘红，推测是由于版本号和父项目不一致导致的，先不用管（有强迫症的孩子可以尝试解决） 。 是由于maven版本过低导致的，maven官网推荐大家更新至3.8.3版本。飘红问题即可解决（如果还飘红，可以先输入版本号，刷新pom.xml文件后再删除版本号即可）

3. 新建子模块blog-api

3.1 pom.xml添加依赖

        
            org.springframework.boot
            spring-boot-starter
            
            
                
                    org.springframework.boot
                    spring-boot-starter-logging
                
            
        

        
        
            org.springframework.boot
            spring-boot-starter-log4j2
        

        
            org.springframework.boot
            spring-boot-starter-aop
        

        
            org.springframework.boot
            spring-boot-starter-mail
        
        
            org.springframework.boot
            spring-boot-starter-web
        

        
            org.springframework.boot
            spring-boot-starter-test
            test
        

        
            org.springframework.boot
            spring-boot-starter-data-redis
        


        
            com.alibaba
            fastjson
            1.2.76
        

        
            mysql
            mysql-connector-java
        
        
            org.springframework.boot
            spring-boot-configuration-processor
            true
        

        
            org.apache.commons
            commons-lang3
        

        
            commons-collections
            commons-collections
            3.2.2
        

        
            com.baomidou
            mybatis-plus-boot-starter
            3.4.3
        
        
            org.projectlombok
            lombok
        
        
        
            joda-time
            joda-time
            2.10.10
        
    

3.2 配置信息

application.properties

#server
server.port=8888
spring.application.name=raxcl

# datasource
spring.datasource.url=jdbc:mysql://106.54.170.191:3306/blog?useUnicode=true&characterEncoding=UTF-8&serverTimeZone=UTC
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

#mybatis-plus
mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl
mybatis-plus.global-config.db-config.table-prefix=ms_

MybatisPlusConfig

package com.raxcl.config;

import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Configurable;

@Configuration
@MapperScan("com.raxcl.blog.mapper")
public class MybatisPlusConfig {

    //分页插件
    public MybatisPlusInterceptor mybatisPlusInterceptor(){
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor());
        return interceptor;
    }
}

WebMVCConfig

package com.raxcl.config;

import org.springframework.beans.factory.annotation.Configurable;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class WebMVCConfig implements WebMvcConfigurer {
    @Override
    public void addCorsMappings(CorsRegistry registry){
        //跨域配置
        registry.addMapping("
    private int commentCounts;

    
    private Long createDate;

    
    private String summary;

    
    private String title;

    
    private  int viewCounts;

    
    private int weight;

    
    private Long authorId;

    
    private Long bodyId;

    
    private int category_id;
}

package com.raxcl.blog.dao.pojo;

import lombok.Data;

@Data
public class SysUser {
    private Long id;

    
    private String account;

    
    private Integer admin;

    
    private String avatar;

    
    private Long createDate;

    
    private Integer deleted;

    
    private String email;

    
    private Long lastLogin;

    
    private String mobilePhoneNumber;

    
    private String nickname;

    
    private String password;

    
    private String salt;

    
    private String status;
}

package com.raxcl.blog.dao.pojo;

import lombok.Data;

@Data
public class Tag {
    private Long id;

    private String avatar;

    private String tagName;
}

1.2.2.2 mapper接口

package com.raxcl.blog.dao.mapper;

import com.baomidou.mybatisplus.core.mapper.baseMapper;
import com.raxcl.blog.dao.pojo.Article;
import org.apache.ibatis.annotations.Mapper;

@Mapper
public interface ArticleMapper extends baseMapper
 {
}

package com.raxcl.blog.dao.mapper;

import com.baomidou.mybatisplus.core.mapper.baseMapper;
import com.raxcl.blog.dao.pojo.SysUser;
import org.apache.ibatis.annotations.Mapper;

@Mapper
public interface SysUserMapper extends baseMapper {
}

package com.raxcl.blog.dao.mapper;

import com.baomidou.mybatisplus.core.mapper.baseMapper;
import com.raxcl.blog.dao.pojo.Tag;
import org.apache.ibatis.annotations.Mapper;

import java.util.List;

@Mapper
public interface TagMapper extends baseMapper {
    
    List findTagByArticleId(Long articleId);
}

1.2.3 vo层

package com.raxcl.blog.vo.param;

import lombok.Data;

@Data
public class PageParams {
    private int page = 1;
    private int pageSize = 10;
}

package com.raxcl.blog.vo;

import lombok.Data;

import java.util.List;

@Data
public class ArticleVo {
    private Long id;

    
    private String title;

    
    private String summary;

    
    private int commentCounts;

    
    private  int viewCounts;

    
    private int weight;

    
    private String createDate;

    
    private String author;

    //private ArticleBodyVo body;

    private List tags;

    //private List categorys;




    
    private Long authorId;

    
    private Long bodyId;

    
    private int category_id;
}

package com.raxcl.blog.vo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Result {
    private boolean success;

    private Integer code;

    private String msg;

    private Object data;

    public static Result success(Object data) {
        return  new Result(true, 200, "success", data);
    }

    public static Result fail(Integer code, String msg){
        return new Result(false,code, msg, null);
    }
}

package com.raxcl.blog.vo;

import lombok.Data;

@Data
public class TagVo {
    private Long id;

    private String tagName;
}

1.2.4 controller层

package com.raxcl.blog.api;

import com.raxcl.blog.service.ArticleService;
import com.raxcl.blog.vo.param.PageParams;
import com.raxcl.blog.vo.Result;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("articles")
public class ArticleController {

    private final ArticleService articleService;


    public ArticleController(ArticleService articleService) {
        this.articleService = articleService;
    }

    //Result是统一结果返回(VO类)
    @PostMapping
    public Result articles(@RequestBody PageParams pageParams){
        return articleService.listArticle(pageParams);
    }
}

1.2.5 service层

package com.raxcl.blog.service;

import com.raxcl.blog.vo.param.PageParams;
import com.raxcl.blog.vo.Result;
import org.springframework.stereotype.Service;


public interface ArticleService {

    
    Result listArticle(PageParams pageParams);
}

package com.raxcl.blog.service.impl;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.raxcl.blog.dao.mapper.ArticleMapper;
import com.raxcl.blog.dao.pojo.Article;
import com.raxcl.blog.service.ArticleService;
import com.raxcl.blog.service.SysUserService;
import com.raxcl.blog.service.TagService;
import com.raxcl.blog.vo.ArticleVo;
import com.raxcl.blog.vo.param.PageParams;
import com.raxcl.blog.vo.Result;
import org.joda.time.DateTime;
import org.springframework.beans.BeanUtils;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.List;

@Service
public class ArticleServiceImpl implements ArticleService {
    private final ArticleMapper articleMapper;
    private final TagService tagService;
    private final SysUserService sysUserService;

    public ArticleServiceImpl(ArticleMapper articleMapper, TagService tagService, SysUserService sysUserService) {
        this.articleMapper = articleMapper;
        this.tagService = tagService;
        this.sysUserService = sysUserService;
    }

    @Override
    public Result listArticle(PageParams pageParams) {
        
        Page
 page = new Page<>(pageParams.getPage(),pageParams.getPageSize());
        LambdaQueryWrapper
 queryWrapper = new LambdaQueryWrapper<>();
        //是否置顶进行排序
         queryWrapper.orderByDesc(Article::getWeight, Article::getCreateDate);
        Page
 articlePage = articleMapper.selectPage(page, queryWrapper);
        //能直接返回吗？ 很明显不能
        List
 records = articlePage.getRecords();
        List articleVoList = copyList(records, true, true);
        return Result.success(articleVoList);
    }

    private List copyList(List
 records, boolean isTag, boolean isAuthor) {
        List articleVoList = new ArrayList<>();
        for (Article record : records){
            articleVoList.add(copy(record,isTag, isAuthor));
        }
        return  articleVoList;
    }

    private ArticleVo copy(Article article, boolean isTag, boolean isAuthor) {
        ArticleVo articleVo = new ArticleVo();
        BeanUtils.copyProperties(article, articleVo);
        articleVo.setCreateDate(new DateTime(article.getCreateDate()).toString("yyyy-MM-dd HH:mm"));
        if (isTag){
            articleVo.setTags(tagService.findTagByArticleId(article.getId()));
        }
        if (isAuthor){
            articleVo.setAuthor(sysUserService.findUserById(article.getId()).getNickname());
        }
        return articleVo;
    }
}

package com.raxcl.blog.service;

import com.raxcl.blog.dao.pojo.SysUser;

public interface SysUserService {
    SysUser findUserById(Long id);
}

package com.raxcl.blog.service.impl;

import com.raxcl.blog.dao.mapper.SysUserMapper;
import com.raxcl.blog.dao.pojo.SysUser;
import com.raxcl.blog.service.SysUserService;
import org.springframework.stereotype.Service;

import java.util.Objects;

@Service
public class SysUserServiceImpl implements SysUserService {
    private final SysUserMapper sysUserMapper;

    public SysUserServiceImpl(SysUserMapper sysUserMapper) {
        this.sysUserMapper = sysUserMapper;
    }

    @Override
    public SysUser findUserById(Long id) {
        SysUser sysUser = sysUserMapper.selectById(id);
        if (Objects.isNull(sysUser)){
            sysUser = new SysUser();
            sysUser.setNickname("raxcl学博客");
        }
        return sysUser;
    }
}

package com.raxcl.blog.service;

import com.raxcl.blog.vo.TagVo;

import java.util.List;

public interface TagService {
    List findTagByArticleId(Long articleId);
}

package com.raxcl.blog.service.impl;

import com.raxcl.blog.dao.mapper.TagMapper;
import com.raxcl.blog.dao.pojo.Article;
import com.raxcl.blog.dao.pojo.Tag;
import com.raxcl.blog.service.TagService;
import com.raxcl.blog.vo.ArticleVo;
import com.raxcl.blog.vo.TagVo;
import org.joda.time.DateTime;
import org.springframework.beans.BeanUtils;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.List;

@Service
public class TagServiceImpl implements TagService {

    private final TagMapper tagMapper;

    public TagServiceImpl(TagMapper tagMapper) {
        this.tagMapper = tagMapper;
    }

    @Override
    public List findTagByArticleId(Long articleId) {
        //mybatisplus 无法进行多表查询？
        List tags = tagMapper.findTagByArticleId(articleId);
        return copyList(tags);
    }

    private List copyList(List records) {
        List tagVoList = new ArrayList<>();
        for (Tag record : records){
            tagVoList.add(copy(record));
        }
        return  tagVoList;
    }

    private TagVo copy(Tag tag) {
        TagVo tagVo = new TagVo();
        BeanUtils.copyProperties(tag, tagVo);
        return tagVo;
    }
}

1.2.6 mapper实现层

    
        select id,avatar,tag_name
        from ms_tag
        where id in (
                select tag_id from ms_article_tag where article_id=#{articleId}
            )
    

 
2. 首页-最热标签 
2.1 接口说明 
接口url：/tags/hot
 
请求方式：GET
 
请求参数：无
 
返回数据：
 
{
    "success": true,
    "code": 200,
    "msg": "success",
    "data": [
        {
            "id":1,
            "tagName":"4444"
        }
    ]
}
 
2.2 编码 
2.2.1 controller层 
package com.raxcl.blog.api;

import com.raxcl.blog.service.TagService;
import com.raxcl.blog.vo.Result;
import com.raxcl.blog.vo.TagVo;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
@RequestMapping("tags")
public class TagsController {

    private final TagService tagService;

    public TagsController(TagService tagService) {
        this.tagService = tagService;
    }


    @GetMapping("/hot")
    public Result listHotTags() {
        int limit = 6;
        List tagVoList = tagService.hot(limit);
        return Result.success(tagVoList);
    }
}


 
2.2.2 service层 
package com.raxcl.blog.service;

import com.raxcl.blog.vo.TagVo;

import java.util.List;

public interface TagService {
    List hot(int limit);
}

 
package com.raxcl.blog.service.impl;

import com.raxcl.blog.dao.mapper.TagMapper;
import com.raxcl.blog.dao.pojo.Article;
import com.raxcl.blog.dao.pojo.Tag;
import com.raxcl.blog.service.TagService;
import com.raxcl.blog.vo.ArticleVo;
import com.raxcl.blog.vo.TagVo;
import org.joda.time.DateTime;
import org.springframework.beans.BeanUtils;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.List;

@Service
public class TagServiceImpl implements TagService {

     @Override
    public List hot(int limit) {
        List hotsTagIds = tagMapper.findHotsTagIds(limit);
        if (CollectionUtils.isEmpty(hotsTagIds)){
            return Collections.emptyList();
        }
        List tagList = tagMapper.findTagsByTagIds(hotsTagIds);
        return copyList(tagList);
    }
}

 
2.2.3 mapper层 
package com.raxcl.blog.dao.mapper;

import com.baomidou.mybatisplus.core.mapper.baseMapper;
import com.raxcl.blog.dao.pojo.Tag;
import com.raxcl.blog.vo.TagVo;
import org.apache.ibatis.annotations.Mapper;

import java.util.List;

@Mapper
public interface TagMapper extends baseMapper {

    
    List findHotsTagIds(int limit);

    List findTagsByTagIds(List tagIds);

}

 






    
        id,avatar,tag_name
    

    
        select tag_id
        from ms_article_tag
        group by tag_id
        order by count(1) desc limit #{size}
    

    
        select 
        from ms_tag
        where id in
        
            #{tagId}
        

    

 
3. 统一处理异常 
package com.raxcl.blog.handler;

import com.raxcl.blog.vo.Result;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;

//对加了@Controller注解的方法进行拦截处理 AOP实现
@ControllerAdvice
public class AllExceptionHandler {
    //进行异常处理，处理Exception.class的异常
    @ExceptionHandler(Exception.class)
    @ResponseBody
    public Result doException(Exception e){
        e.printStackTrace();
        return Result.fail(-999,"系统异常");
    }
}

 
4. 首页-最热文章&最新文章 
4.1 接口说明 
最热文章：
 接口url：/articles/hot
 请求方式：POST
 请求参数：
 
最新文章:
 接口url：/articles/new
 请求方式：POST
 请求参数：
 
4.2 controller层 
package com.raxcl.blog.api;

import com.raxcl.blog.service.ArticleService;
import com.raxcl.blog.vo.param.PageParams;
import com.raxcl.blog.vo.Result;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("articles")
public class ArticleController {
    
    @PostMapping("hot")
    public Result hotArticle(){
        int limit = 5;
        return articleService.hotArticle(limit);
    }

    
    @PostMapping("new")
    public Result newArticle(){
        int limit = 5;
        return articleService.newArticle(limit);
    }
}
 
4.3 service层 
package com.raxcl.blog.service;

import com.raxcl.blog.vo.param.PageParams;
import com.raxcl.blog.vo.Result;

public interface ArticleService {

    Result hotArticle(int limit);

    Result newArticle(int limit);
}

 
package com.raxcl.blog.service.impl;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.raxcl.blog.dao.mapper.ArticleMapper;
import com.raxcl.blog.dao.pojo.Article;
import com.raxcl.blog.service.ArticleService;
import com.raxcl.blog.service.SysUserService;
import com.raxcl.blog.service.TagService;
import com.raxcl.blog.vo.ArticleVo;
import com.raxcl.blog.vo.param.PageParams;
import com.raxcl.blog.vo.Result;
import org.joda.time.DateTime;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.List;

@Service
public class ArticleServiceImpl implements ArticleService {
    @Override
    public Result hotArticle(int limit) {
        LambdaQueryWrapper
 queryWrapper = new LambdaQueryWrapper<>();
        queryWrapper.orderByDesc(Article::getViewCounts);
        queryWrapper.select(Article::getId,Article::getTitle);
        queryWrapper.last("limit "+ limit);
        List
 articles = articleMapper.selectList(queryWrapper);
        return Result.success(copyList(articles,false,false));
    }

    @Override
    public Result newArticle(int limit) {
        LambdaQueryWrapper
 queryWrapper = new LambdaQueryWrapper<>();
        queryWrapper.orderByDesc(Article::getCreateDate);
        queryWrapper.select(Article::getId,Article::getTitle);
        queryWrapper.last("limit "+ limit);
        List
 articles = articleMapper.selectList(queryWrapper);
        return Result.success(copyList(articles,false,false));
    }

}

 
5. 首页-文章归档 
5.1 接口说明 
接口url：/articles/listArchives
 
请求方式：POST
 
5.2 dto层 
package com.raxcl.blog.dao.dto;

import lombok.Data;

@Data
public class Archives {
    private Integer year;

    private Integer month;

    private Integer count;
}

 
5.3 controller层 
package com.raxcl.blog.api;

import com.raxcl.blog.service.ArticleService;
import com.raxcl.blog.vo.param.PageParams;
import com.raxcl.blog.vo.Result;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("articles")
public class ArticleController {
    
    @PostMapping("listArchives")
    public Result listArchives(){
        return articleService.listArchives();
    }
}
 
5.3 service层 
package com.raxcl.blog.service;

import com.raxcl.blog.vo.param.PageParams;
import com.raxcl.blog.vo.Result;

public interface ArticleService {

    Result listArchives();
}

 
package com.raxcl.blog.service.impl;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.raxcl.blog.dao.mapper.ArticleMapper;
import com.raxcl.blog.dao.pojo.Article;
import com.raxcl.blog.service.ArticleService;
import com.raxcl.blog.service.SysUserService;
import com.raxcl.blog.service.TagService;
import com.raxcl.blog.vo.ArticleVo;
import com.raxcl.blog.vo.param.PageParams;
import com.raxcl.blog.vo.Result;
import org.joda.time.DateTime;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.List;

@Service
public class ArticleServiceImpl implements ArticleService {
    
    @PostMapping("listArchives")
    public Result listArchives(){
        return articleService.listArchives();
    }
}

 
5.4 mapper层 
package com.raxcl.blog.dao.mapper;

import com.baomidou.mybatisplus.core.mapper.baseMapper;
import com.raxcl.blog.dao.dto.Archives;
import com.raxcl.blog.dao.pojo.Article;
import org.apache.ibatis.annotations.Mapper;

import java.util.List;

@Mapper
public interface ArticleMapper extends baseMapper
 {
    List listArchives();
}

 





    
        select year(create_date) year, month(create_date) month, count(*) count
        from ms_article
        group by year, month
    

6. 登录功能 6.1 接口说明

接口url：/login

请求方式：POST

请求参数：

参数名称	参数类型	说明
account	string	账号
password	string	密码

返回数据：

{
    "success": true,
    "code": 200,
    "msg": "success",
    "data": "token"
}

6.2 pom.xml

        
        
            commons-codec
            commons-codec
        

6.3 vo层

package com.raxcl.blog.vo.param;

import lombok.Data;

@Data
public class LoginParam {
    private String account;

    private String password;
}

package com.raxcl.blog.vo;

public enum ErrorCode {


    PARAMS_ERROR(10001,"参数有误"),

    ACCOUNT_PWD_NOT_EXIST (10002,"用户名或密码不存在"),;

    private int code;
    private String msg;

    ErrorCode(int code, String msg) {
		this.code = code;
        this.msg = msg;
    }

    public int getCode() {
        return code;
    }

    public void setCode(int code) {
        this.code = code;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }
}

6.4 utils层

package com.raxcl.blog.utils;

import io.jsonwebtoken.*;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;

public class JWTUtils {
    private static final String jwtToken = "123456Mszlu!@#$$";

    public static String createToken(Long userId){
        Map claims = new HashMap<>();
        claims.put("userId",userId);
        JwtBuilder jwtBuilder = Jwts.builder()
                .signWith(SignatureAlgorithm.HS256, jwtToken) //签发算法，秘钥为jwtToken
                .setClaims(claims) //body数据，要唯一，自行设置
                .setIssuedAt(new Date()) // 设置签发时间
                .setExpiration(new Date(System.currentTimeMillis() + 24 * 60 * 60 * 60 * 1000));//一天的有效时间
        String token = jwtBuilder.compact();
        return token;
    }

    public static Map checkToken(String token){
        try {
            Jwt parse = Jwts.parser().setSigningKey(jwtToken).parse(token);
            return (Map) parse.getBody();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }


}

6.5 controller层

package com.raxcl.blog.controller;

import com.raxcl.blog.service.LoginService;
import com.raxcl.blog.vo.Result;
import com.raxcl.blog.vo.param.LoginParam;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("login")
public class LoginController {
    private final LoginService loginService;

    public LoginController(LoginService loginService) {
        this.loginService = loginService;
    }

    @PostMapping
    public Result login(@RequestBody LoginParam loginParam){
        return loginService.login(loginParam);
    }
}

6.6 service层

package com.raxcl.blog.service;

import com.raxcl.blog.vo.Result;
import com.raxcl.blog.vo.param.LoginParam;

public interface LoginService {
    
    Result login(LoginParam loginParam);
}

package com.raxcl.blog.service.impl;

import com.alibaba.fastjson.JSON;
import com.raxcl.blog.dao.pojo.SysUser;
import com.raxcl.blog.service.LoginService;
import com.raxcl.blog.service.SysUserService;
import com.raxcl.blog.utils.JWTUtils;
import com.raxcl.blog.vo.ErrorCode;
import com.raxcl.blog.vo.Result;
import com.raxcl.blog.vo.param.LoginParam;
import org.apache.commons.codec.digest.DigestUtils;
import org.apache.commons.lang3.StringUtils;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;

import java.util.Objects;
import java.util.concurrent.TimeUnit;

@Service
public class LoginServiceImpl implements LoginService {

    private static final String slat = "raxcl!@#";

    private final SysUserService sysUserService;
    private final RedisTemplate redisTemplate;

    public LoginServiceImpl(SysUserService sysUserService, RedisTemplate redisTemplate) {
        this.sysUserService = sysUserService;
        this.redisTemplate = redisTemplate;
    }

    @Override
    public Result login(LoginParam loginParam) {
        String account = loginParam.getAccount();
        String password = loginParam.getPassword();
        if (StringUtils.isBlank(account) || StringUtils.isBlank(password)){
            return Result.fail(ErrorCode.PARAMS_ERROR.getCode(),ErrorCode.PARAMS_ERROR.getMsg());
        }
        String pwd = DigestUtils.md5Hex(password + slat);
        SysUser sysUser = sysUserService.findUser(account,pwd);
        if (Objects.isNull(sysUser)){
            return Result.fail(ErrorCode.ACCOUNT_PWD_NOT_EXIST.getCode(),ErrorCode.ACCOUNT_PWD_NOT_EXIST.getMsg());
        }
        //登录成功，使用JWT生成token，返回token和redis中
        String token = JWTUtils.createToken(sysUser.getId());
        redisTemplate.opsForValue().set("TOKEN_"+token, JSON.toJSONString(sysUser),1, TimeUnit.DAYS);
        return Result.success(token);
    }

}

package com.raxcl.blog.service;

import com.raxcl.blog.dao.pojo.SysUser;

public interface SysUserService {

    SysUser findUser(String account, String pwd);
}

package com.raxcl.blog.service.impl;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.raxcl.blog.dao.mapper.SysUserMapper;
import com.raxcl.blog.dao.pojo.SysUser;
import com.raxcl.blog.service.SysUserService;
import org.springframework.stereotype.Service;

import java.util.Objects;

@Service
public class SysUserServiceImpl implements SysUserService {
    @Override
    public SysUser findUser(String account, String pwd) {
        LambdaQueryWrapper queryWrapper = new LambdaQueryWrapper<>();
        queryWrapper.eq(SysUser::getAccount,account);
        queryWrapper.eq(SysUser::getPassword,pwd);
        queryWrapper.select(SysUser::getId,SysUser::getAccount,SysUser::getAvatar,SysUser::getNickname);
        queryWrapper.last("limit 1");
        SysUser sysUser = sysUserMapper.selectOne(queryWrapper);
        return sysUser;
    }
}

7. 获取用户信息 7.1 接口说明

接口url：/users/currentUser

请求方式：GET

请求参数：

参数名称	参数类型	说明
Authorization	string	头部信息(TOKEN)

返回数据：

{
    "success": true,
    "code": 200,
    "msg": "success",
    "data": {
        "id":1,
        "account":"1",
        "nickaname":"1",
        "avatar":"ss"
    }
}

7.2 controller层

package com.raxcl.blog.controller;

import com.raxcl.blog.service.SysUserService;
import com.raxcl.blog.vo.Result;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("users")
public class UserController {
    private final SysUserService sysUserService;

    public UserController(SysUserService sysUserService) {
        this.sysUserService = sysUserService;
    }

    @GetMapping("currentUser")
    public Result currentUser (@RequestHeader("Authorization") String token){
        return sysUserService.getUserInfoByToken(token);
    }
}

7.3 vo层

package com.raxcl.blog.vo;

import lombok.Data;

@Data
public class LoginUserVo {
    private Long id;

    private String account;

    private  String nickname;

    private String avatar;
}

7.4 service层

package com.raxcl.blog.service;

import com.raxcl.blog.dao.pojo.SysUser;
import com.raxcl.blog.vo.Result;

public interface SysUserService {
    Result getUserInfoByToken(String token);
}

package com.raxcl.blog.service.impl;

import com.alibaba.fastjson.JSON;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.raxcl.blog.dao.mapper.SysUserMapper;
import com.raxcl.blog.dao.pojo.SysUser;
import com.raxcl.blog.service.SysUserService;
import com.raxcl.blog.utils.JWTUtils;
import com.raxcl.blog.vo.ErrorCode;
import com.raxcl.blog.vo.LoginUserVo;
import com.raxcl.blog.vo.Result;
import org.apache.commons.lang3.StringUtils;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;

import java.util.Map;
import java.util.Objects;

@Service
public class SysUserServiceImpl implements SysUserService {
    private final SysUserMapper sysUserMapper;
    private final RedisTemplate redisTemplate;

    public SysUserServiceImpl(SysUserMapper sysUserMapper, RedisTemplate redisTemplate) {
        this.sysUserMapper = sysUserMapper;
        this.redisTemplate = redisTemplate;

    }
    
    @Override
    public Result getUserInfoByToken(String token) {
        Map map = JWTUtils.checkToken((token));
        if (Objects.isNull(map)){
            return Result.fail(ErrorCode.NO_LOGIN.getCode(),ErrorCode.NO_LOGIN.getMsg());
        }
        String userJson = redisTemplate.opsForValue().get("TOKEN_" + token);
        if (StringUtils.isBlank(userJson)){
            return Result.fail(ErrorCode.NO_LOGIN.getCode(), ErrorCode.NO_LOGIN.getMsg());
        }
        SysUser sysUser = JSON.parseObject(userJson, SysUser.class);
        LoginUserVo loginUserVo = new LoginUserVo();
        loginUserVo.setAccount(sysUser.getAccount());
        loginUserVo.setAvatar(sysUser.getAvatar());
        loginUserVo.setId(sysUser.getId());
        loginUserVo.setNickname(sysUser.getNickname());
        return Result.success(loginUserVo);
    }
}

8. 登出

接口url：/logout

请求方式：GET

请求参数：

参数名称	参数类型	说明
Authorization	string	头部信息(TOKEN)

返回数据：

{
    "success": true,
    "code": 200,
    "msg": "success",
    "data": null
}

8.1 controller层

package com.raxcl.blog.controller;

import com.raxcl.blog.service.LoginService;
import com.raxcl.blog.vo.Result;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("logout")
public class LogoutController {
    private final LoginService loginService;

    public LogoutController(LoginService loginService) {
        this.loginService = loginService;
    }

    @GetMapping
    public Result logout(@RequestHeader("Authorization") String token){
        return loginService.logout(token);
    }
}

8.2 service层

package com.raxcl.blog.service;

import com.raxcl.blog.vo.Result;
import com.raxcl.blog.vo.param.LoginParam;

public interface LoginService {

    Result logout(String token);
}

package com.raxcl.blog.service.impl;

import com.alibaba.fastjson.JSON;
import com.raxcl.blog.dao.pojo.SysUser;
import com.raxcl.blog.service.LoginService;
import com.raxcl.blog.service.SysUserService;
import com.raxcl.blog.utils.JWTUtils;
import com.raxcl.blog.vo.ErrorCode;
import com.raxcl.blog.vo.Result;
import com.raxcl.blog.vo.param.LoginParam;
import org.apache.commons.codec.digest.DigestUtils;
import org.apache.commons.lang3.StringUtils;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;

import java.util.Objects;
import java.util.concurrent.TimeUnit;

@Service
public class LoginServiceImpl implements LoginService {
    @Override
    public Result logout(String token) {
        redisTemplate.delete("TOLEN_"+token);
        return Result.success(null);
    }

}

9. 注册 9.1 接口说明

接口url：/register

请求方式：POST

请求参数：

参数名称	参数类型	说明
account	string	账号
password	string	密码
nickname	string	昵称

返回数据：

{
    "success": true,
    "code": 200,
    "msg": "success",
    "data": "token"
}

9.2 vo层

package com.raxcl.blog.vo.param;

import lombok.Data;

@Data
public class LoginParam {
    private String account;

    private String password;

    private String nickname;
}

package com.raxcl.blog.vo;

public enum ErrorCode {


    PARAMS_ERROR(10001,"参数有误"),
    ACCOUNT_PWD_NOT_EXIST (10002,"用户名或密码不存在"),
    NO_PERMISSION(70001,"无访问权限"),
    SESSION_TIME_OUT(90001,"会话超时"),
    NO_LOGIN(90002,"未登录"),
    ACCOUNT_EXIST(10004,"账号已存在");
}

9.3 controller层

package com.raxcl.blog.controller;

import com.raxcl.blog.service.LoginService;
import com.raxcl.blog.vo.Result;
import com.raxcl.blog.vo.param.LoginParam;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("register")
public class RegisterController {
    private final LoginService loginService;

    public RegisterController(LoginService loginService) {
        this.loginService = loginService;
    }

    @PostMapping
    public Result register(@RequestBody LoginParam loginParam){
        return loginService.register(loginParam);
    }
}

9.4 service层

package com.raxcl.blog.service;

import com.raxcl.blog.vo.Result;
import com.raxcl.blog.vo.param.LoginParam;

public interface LoginService {

    Result register(LoginParam loginParam);
}

package com.raxcl.blog.service.impl;

import com.alibaba.fastjson.JSON;
import com.raxcl.blog.dao.pojo.SysUser;
import com.raxcl.blog.service.LoginService;
import com.raxcl.blog.service.SysUserService;
import com.raxcl.blog.utils.JWTUtils;
import com.raxcl.blog.vo.ErrorCode;
import com.raxcl.blog.vo.Result;
import com.raxcl.blog.vo.param.LoginParam;
import org.apache.commons.codec.digest.DigestUtils;
import org.apache.commons.lang3.StringUtils;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.Objects;
import java.util.concurrent.TimeUnit;

@Service
@Transactional
public class LoginServiceImpl implements LoginService {

    private static final String slat = "raxcl!@#";

    private final SysUserService sysUserService;
    private final RedisTemplate redisTemplate;

    public LoginServiceImpl(SysUserService sysUserService, RedisTemplate redisTemplate) {
        this.sysUserService = sysUserService;
        this.redisTemplate = redisTemplate;
    }

    @Override
    public Result register(LoginParam loginParam) {
        String account = loginParam.getAccount();
        String password = loginParam.getPassword();
        String nickname = loginParam.getNickname();
        if (StringUtils.isBlank(account) || StringUtils.isBlank(password) || StringUtils.isBlank(nickname)){
            return Result.fail(ErrorCode.PARAMS_ERROR.getCode(), ErrorCode.PARAMS_ERROR.getMsg());
        }
        SysUser sysUser = this.sysUserService.findUserByAccount(account);
        if (sysUser != null){
            return Result.fail(ErrorCode.ACCOUNT_EXIST.getCode(),ErrorCode.ACCOUNT_EXIST.getMsg());
        }
        sysUser = new SysUser();
        sysUser.setNickname(nickname);
        sysUser.setAccount(account);
        sysUser.setPassword(DigestUtils.md5Hex(password+slat));
        sysUser.setCreateDate(System.currentTimeMillis());
        sysUser.setLastLogin(System.currentTimeMillis());
        sysUser.setAvatar("/static/img/logo.b3a48c0.png");
        sysUser.setAdmin(1); // 1为true
        sysUser.setDeleted(0); //0为false
        sysUser.setSalt("");
        sysUser.setStatus("");
        sysUser.setEmail("");
        this.sysUserService.save(sysUser);

        //token
        String token = JWTUtils.createToken(sysUser.getId());
        redisTemplate.opsForValue().set("TOKEN_"+token,JSON.toJSONString(sysUser),1,TimeUnit.DAYS);
        return Result.success(token);
    }

}

package com.raxcl.blog.service;

import com.raxcl.blog.dao.pojo.SysUser;
import com.raxcl.blog.vo.Result;

public interface SysUserService {

    SysUser findUserByAccount(String account);

    void save(SysUser sysUser);
}

package com.raxcl.blog.service.impl;

import com.alibaba.fastjson.JSON;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.raxcl.blog.dao.mapper.SysUserMapper;
import com.raxcl.blog.dao.pojo.SysUser;
import com.raxcl.blog.service.SysUserService;
import com.raxcl.blog.utils.JWTUtils;
import com.raxcl.blog.vo.ErrorCode;
import com.raxcl.blog.vo.LoginUserVo;
import com.raxcl.blog.vo.Result;
import org.apache.commons.lang3.StringUtils;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;

import java.util.Map;
import java.util.Objects;

@Service
public class SysUserServiceImpl implements SysUserService {
    private final SysUserMapper sysUserMapper;
    private final RedisTemplate redisTemplate;

    public SysUserServiceImpl(SysUserMapper sysUserMapper, RedisTemplate redisTemplate) {
        this.sysUserMapper = sysUserMapper;
        this.redisTemplate = redisTemplate;

    }
    @Override
    public SysUser findUserByAccount(String account) {
        LambdaQueryWrapper queryWrapper = new LambdaQueryWrapper<>();
        queryWrapper.eq(SysUser::getAccount,account);
        queryWrapper.last("limit 1");
        return sysUserMapper.selectOne(queryWrapper);
    }

    @Override
    public void save(SysUser sysUser) {
        //注意 默认生成的id是分布式id 采用了雪花算法
        this.sysUserMapper.insert(sysUser);
    }
}

10. 登录拦截器

每次访问需要登录的资源的时候，都需要在代码中进行判断，一旦登录的逻辑有所改变，代码都得进行变动，非常不合适。

那么可不可以统一进行登录判断呢？

可以，使用拦截器，进行登录拦截，如果遇到需要登录才能访问的接口，如果未登录，拦截器直接返回，并跳转登录页面。

10.1 hander层

package com.raxcl.blog.handler;

import com.alibaba.fastjson.JSON;
import com.raxcl.blog.dao.pojo.SysUser;
import com.raxcl.blog.service.LoginService;
import com.raxcl.blog.vo.ErrorCode;
import com.raxcl.blog.vo.Result;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@Component
@Slf4j
public class LoginInterceptor implements HandlerInterceptor {
    private final LoginService loginService;

    public LoginInterceptor(LoginService loginService) {
        this.loginService = loginService;
    }

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        if(!(handler instanceof HandlerMethod)){
            return true;
        }
        String token = request.getHeader("Authorization");
        log.info("==============request start=================");
        String requestURI = request.getRequestURI();
        log.info("request uri:{}",requestURI);
        log.info("request method:{}",request.getMethod());
        log.info("token:{}",token);
        log.info("==============request end===============");
        if (token == null){
            Result result = Result.fail(ErrorCode.NO_LOGIN.getCode(), "未登录");
            response.setContentType("application/json;charset=utf-8");
            response.getWriter().print(JSON.toJSONString(result));
            return false;
        }
        SysUser sysUser = loginService.checkToken(token);
        if (sysUser == null){
            Result result = Result.fail(ErrorCode.NO_LOGIN.getCode(), "未登录");
            response.setContentType("application/json;charset=utf-8");
            response.getWriter().print(JSON.toJSONString(result));
            return false;
        }
        //是登录状态，放行
        return true;
    }

}

10.2 service层

package com.raxcl.blog.service;

import com.raxcl.blog.dao.pojo.SysUser;
import com.raxcl.blog.vo.Result;
import com.raxcl.blog.vo.param.LoginParam;

public interface LoginService {
    SysUser checkToken(String token);
}

package com.raxcl.blog.service.impl;

import com.alibaba.fastjson.JSON;
import com.raxcl.blog.dao.pojo.SysUser;
import com.raxcl.blog.service.LoginService;
import com.raxcl.blog.service.SysUserService;
import com.raxcl.blog.utils.JWTUtils;
import com.raxcl.blog.vo.ErrorCode;
import com.raxcl.blog.vo.Result;
import com.raxcl.blog.vo.param.LoginParam;
import org.apache.commons.codec.digest.DigestUtils;
import org.apache.commons.lang3.StringUtils;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.Map;
import java.util.Objects;
import java.util.concurrent.TimeUnit;

@Service
@Transactional
public class LoginServiceImpl implements LoginService {
    @Override
    public SysUser checkToken(String token) {
        if (StringUtils.isBlank(token)){
            return null;
        }
        Map stringObjectMap = JWTUtils.checkToken(token);
        if (stringObjectMap == null){
            return null;
        }
        String userJson = redisTemplate.opsForValue().get("TOKEN_"+ token);
        if (StringUtils.isBlank(userJson)){
            return null;
        }
        SysUser sysUser = JSON.parseObject(userJson, SysUser.class);
        return sysUser;
    }


}

10.3 config层（使拦截器生效）

package com.raxcl.blog.config;

import com.raxcl.blog.handler.LoginInterceptor;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class WebMVCConfig implements WebMvcConfigurer {

    private final LoginInterceptor loginInterceptor;

    public WebMVCConfig(LoginInterceptor loginInterceptor) {
        this.loginInterceptor = loginInterceptor;
    }

    @Override
    public void addInterceptors(InterceptorRegistry registry){
        //拦截test接口，后续实际遇到需要拦截的接口时，在配置为真正的拦截接口
        registry.addInterceptor(loginInterceptor).addPathPatterns("/test");
    }


}

10.4 测试层（controller）

package com.raxcl.blog.controller;

import com.raxcl.blog.vo.Result;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("test")
public class TestController {
    @RequestMapping
    public Result test(){
        return Result.success(null);
    }
}

11. ThreadLocal保存用户信息 11.1 utils层

package com.raxcl.blog.utils;

import com.raxcl.blog.dao.pojo.SysUser;

public class UserThreadLocal {
    private UserThreadLocal(){}

    private static final ThreadLocal LOCAL = new ThreadLocal<>();

    public static void put(SysUser sysUser){
        LOCAL.set(sysUser);
    }
    public static SysUser get(){
        return LOCAL.get();
    }
    public static void remove(){
        LOCAL.remove();
    }

}

11.2 handler层

package com.raxcl.blog.handler;

import com.alibaba.fastjson.JSON;
import com.raxcl.blog.dao.pojo.SysUser;
import com.raxcl.blog.service.LoginService;
import com.raxcl.blog.utils.UserThreadLocal;
import com.raxcl.blog.vo.ErrorCode;
import com.raxcl.blog.vo.Result;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@Component
@Slf4j
public class LoginInterceptor implements HandlerInterceptor {
    private final LoginService loginService;

    public LoginInterceptor(LoginService loginService) {
        this.loginService = loginService;
    }

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        //在执行controller方法之前进行执行
        //在执行controller方法(Handler)之前进行执行
        
        if(!(handler instanceof HandlerMethod)){
            return true;
        }
        String token = request.getHeader("Authorization");
        log.info("==============request start=================");
        String requestURI = request.getRequestURI();
        log.info("request uri:{}",requestURI);
        log.info("request method:{}",request.getMethod());
        log.info("token:{}",token);
        log.info("==============request end===============");
        if (token == null){
            Result result = Result.fail(ErrorCode.NO_LOGIN.getCode(), "未登录");
            response.setContentType("application/json;charset=utf-8");
            response.getWriter().print(JSON.toJSONString(result));
            return false;
        }
        SysUser sysUser = loginService.checkToken(token);
        if (sysUser == null){
            Result result = Result.fail(ErrorCode.NO_LOGIN.getCode(), "未登录");
            response.setContentType("application/json;charset=utf-8");
            response.getWriter().print(JSON.toJSONString(result));
            return false;
        }
        //是登录状态，放行
        UserThreadLocal.put(sysUser);
        return true;
    }

    
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response,
                                Object handler, Exception ex){
        UserThreadLocal.remove();
    }

}

11.3 controller层

package com.raxcl.blog.controller;

import com.raxcl.blog.utils.UserThreadLocal;
import com.raxcl.blog.vo.Result;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("test")
public class TestController {
    @RequestMapping
    public Result test(){
        System.out.println("哈哈哈哈哈哈");
        System.out.println(UserThreadLocal.get());
        return Result.success(null);
    }
}

12. ThreadLocal内存泄漏

实线代表强引用,虚线代表弱引用

每一个Thread维护一个ThreadLocalMap, key为使用弱引用的ThreadLocal实例，value为线程变量的副本。

强引用，使用最普遍的引用，一个对象具有强引用，不会被垃圾回收器回收。当内存空间不足，Java虚拟机宁愿抛出OutOfMemoryError错误，使程序异常终止，也不回收这种对象。

如果想取消强引用和某个对象之间的关联，可以显式地将引用赋值为null，这样可以使JVM在合适的时间就会回收该对象。

弱引用，JVM进行垃圾回收时，无论内存是否充足，都会回收被弱引用关联的对象。在java中，用java.lang.ref.WeakReference类来表示。