springboot+postsql 做接口api

    4.0.0
    
        org.springframework.boot
        spring-boot-starter-parent
        2.6.7
         
    
    com.example
    demo4
    0.0.1-SNAPSHOT
    demo4
    demo4
    
        1.8
    
    
        
            org.springframework.boot
            spring-boot-starter-web
        
        
            org.mybatis.spring.boot
            mybatis-spring-boot-starter
            2.2.2
        

        
            mysql
            mysql-connector-java
            runtime
        
        
            org.projectlombok
            lombok
            true
        
        
            org.springframework.boot
            spring-boot-starter-test
            test
        
        
            org.postgresql
            postgresql
            runtime
        
    

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

        
            
                src/main/java
                
                    **/*.xml
                
                true
            
        
    

项目pom所需的所有依赖

spring.datasource.username=dbuser
spring.datasource.password=12345678
spring.datasource.driver-class-name=org.postgresql.Driver
spring.datasource.url=jdbc:postgresql://localhost:12345/imag002
mybatis.type-aliases-package=com.example.demo.pojo
mybatis.mapper-locations=classpath:mybatis/mapper/**.xml

首先在idea当中连接好我们服务器数据库，连接成功后开始配数据库文件

项目结构如图所示，需要在application.properties当中设定好pojo包的别名，以及需要设置好mapper.xml文件扫描包

package com.example.demo.pojo;

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

@Data
@NoArgsConstructor
@AllArgsConstructor
public class Conference {
    private String name;
    private  String author;
    private  String conf_name;
    private  String organizer;
    private  String conf_dat;
    private  String dat;
    private  String employ;
}

 pojo模块，设置@data 和无参有参构造

package com.example.demo.mapper;

import com.example.demo.pojo.Conference;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;

import java.util.List;
@Mapper
@Repository
public interface ConferenceMapper {
    List queryall();
}

然后这是mapper接口，我们这里只设置了一个求所有论文的方法

接下来我们需要写一个xml来实现这个接口

package com.example.demo.mapper;

import com.example.demo.pojo.Conference;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;

import java.util.List;
@Mapper
@Repository
public interface ConferenceMapper {
    List queryall();
}

在resource文件夹下面 新建mybites.mapper

把xml文件放在该目录下面

package com.example.demo.controller;

import com.example.demo.mapper.ConferenceMapper;
import com.example.demo.pojo.Conference;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
public class Controller {
    @Autowired
    ConferenceMapper conferenceMapper;
    @GetMapping("/honors")
    public List getall(){
        return conferenceMapper.queryall();
    }

controller 记得注解 restcontroller  然后getmapping 

 测试结果 ，完美！

另外，在连接数据库时，要显示所有表的步骤：