个人笔记（Mybatis-Plus）

1.maven依赖包：

        
        
            com.baomidou
            mybatis-plus
            3.3.2
        

2. applicationContext：

 3.Mybatis-config.xml:

 4. MyBatis-Plus核心注解(在实体类（entity）中使用)

@TableName //-将实体类与表名映射

@Tableld //-说明对应属性是表的主键

@TableField //-设置属性与列名的对应关系

案例：

@TableName("test") //说明实体对应哪一张表
public class Test {
    @TableId(type = IdType.AUTO)  //主键
    @TableField("id")
    private Integer id;

    @TableField("content")  //如果字段名与属性名相同或者符合驼峰命名转换规则，则TableField可省略
    private String content;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }
}

5. 接口(mapper)设置，注意导入接口BaseMapper：

package com.imooc.reader.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.imooc.reader.entity.Test;


public interface TestMapper extends BaseMapper {
    public void insertSample();
}

6.接口对应的xml文件：（案例）

6. BaseMapper接口核心API6 

 案例：

package com.imooc.reader.service;


import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.imooc.reader.entity.Test;
import com.imooc.reader.mapper.TestMapper;
import org.junit.runner.RunWith;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import javax.annotation.Resource;
import java.util.List;

@RunWith(SpringJUnit4ClassRunner.class) //junit4运行的时候自动初始化IOC容器
@ContextConfiguration(locations = {"classpath:applicationContext.xml"})
//上面@ 的两项是Test文件专用的注解
public class MyBatisPlusTest {
    @Resource
    private TestMapper testMapper;

    @org.junit.Test
    public void testInsert(){
        Test test=new Test();
        test.setContent("MyBatis Plus测试1");
        testMapper.insert(test);

    }
    @org.junit.Test
    public void testUpdate(){
        Test test=testMapper.selectById(48);
        test.setContent("wwx");
        testMapper.updateById(test);
    }
    @org.junit.Test
    public void testDelete(){
        testMapper.deleteById(48);
    }
    @org.junit.Test
    public void testSelect(){
//        查询条件构造器
        QueryWrapper queryWrapper=new QueryWrapper<>();
//        queryWrapper.eq("id",49);   //id值等于49
        queryWrapper.ge("id",5); //id值大于5
        List list=testMapper.selectList(queryWrapper);
        System.out.println(list.get(0).getContent());
        System.out.println("================================");
    }
}

//选择mysql数据库的表中所有行的数据：

    @GetMapping("/index")
    public ModelAndView showIndex(){
        ModelAndView mav=new ModelAndView("/index");  //只需要文件名字，并不需要后缀,否则ftl文件中无法识别（jsp文件似乎可以）
        List categoryList=categoryService.selectAll();
        mav.addObject("categoryList",categoryList);
        return mav;
    }

//获取分页信息（案例）

impl：

package com.imooc.reader.service.impl;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.imooc.reader.entity.Book;
import com.imooc.reader.mapper.BookMapper;
import com.imooc.reader.service.BookService;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;

@Service("BookService")  //“BookService"与接口名称一致
@Transactional(propagation = Propagation.NOT_SUPPORTED,readOnly = true)  //该类的所有方法不需要开启“事物” ，只读，不改变数据库
public class BookServiceImpl implements BookService {
    @Resource
    private BookMapper bookMapper;

    public IPage paging(Integer page, Integer rows) {
        Page p=new Page(page,rows);     //分页信息 page：第几页 ； rows：每页多少项
        IPage pageObject=bookMapper.selectPage(p,(new QueryWrapper()));   //new QueryWrapper() 选择条件构造器 ；p：分页信息
        return pageObject ;
    }


}

test：

package com.imooc.reader.service.impl;

import com.baomidou.mybatisplus.core.metadata.IPage;
import com.imooc.reader.entity.Book;
import com.imooc.reader.service.BookService;
import junit.framework.TestCase;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import javax.annotation.Resource;
import java.util.List;


@RunWith(SpringJUnit4ClassRunner.class) //junit4运行的时候自动初始化IOC容器
@ContextConfiguration(locations = {"classpath:applicationContext.xml"})
public class BookServiceImplTest extends TestCase {
    @Resource
    private BookService bookService;
    @Test
    public void testPaging() {
        IPage pageObject= bookService.paging(3,10);
        List records=pageObject.getRecords();  //获取记录
        for (Book b:records){
            System.out.println(b.getBookId()+":"+b.getBookName());
        }
        System.out.println("总页数"+":"+pageObject.getPages());
        System.out.println("总记录数"+":"+pageObject.getTotal());
        System.out.println("当前页数"+":"+pageObject.getCurrent());
    }
}