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SpringBoot整合mybatis

2022-12-08 149

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简介： SpringBoot整合mybatis

1.创建springboot项目，勾选Web、JDBC API、 MySql 导入mybatis依赖

<dependency>
       <groupId>org.mybatis.spring.boot</groupId>
       <artifactId>mybatis-spring-boot-starter</artifactId>
       <version>2.2.2</version>
</dependency>

2.在properties或者yml文件配置数据源，绑定Mapper.xml文件

mybatis.type-aliases-package=com.peng.pojo

mybatis.mapper-locations=classpath:mybatis/mapper/UserMapper.xml

以上两句至关重要的

spring.datasource.username=root
spring.datasource.password=1234
spring.datasource.url=jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
#整合关键
mybatis.type-aliases-package=com.peng.pojo
mybatis.mapper-locations=classpath:mybatis/mapper/UserMapper.xml

3.写实体类（用了lombok插件）

package com.peng.pojo;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
private int id;
private String name;
private  String pwd;
}

4.写mapper接口

以下两个注解两种方式

@Mapper//或者在springboot的Application类使用@MapperScan("com.peng.mapper") @Repository//或者@Component

package com.peng.mapper;
import com.peng.pojo.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;
import java.util.List;
@Mapper//或者在springboot的Application类使用@MapperScan("com.peng.mapper")
@Repository//或者@Component
public interface UserMapper {
    List selectAll();
}

5.编写Mapper.xml文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.peng.mapper.UserMapper">
    <select id="selectAll" resultType="User">
    select * from mybatis.user
  </select>
</mapper>

6.编写service层接口，以及Impl实现类

接口：

package com.peng.service;
import com.peng.pojo.User;
import java.util.List;
public interface UserService {
    List selectAll();
}

实现类

package com.peng.service;
import com.peng.mapper.UserMapper;
import com.peng.pojo.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class UserServiceImpl implements UserService {
    private UserMapper userMapper;
    @Autowired
    public void setUserMapper(UserMapper userMapper) {
        this.userMapper = userMapper;
    }
    @Override
    public List selectAll() {
        return userMapper.selectAll();
    }
}

@Service注解用于类上，标记当前类是一个service类，加上该注解会将当前类自动注入到spring容器中，不需要再在applicationContext.xml文件定义bean了。

还需要注入Mapper接口
private UserMapper userMapper;
@Autowired
public void setUserMapper(UserMapper userMapper) {
this.userMapper = userMapper;
}
以上步骤完成在使用的时候只需要注入UserService接口即可使用

7.调用service层

@Controller
public class UserController {
    private UserService userService;
    @Autowired
    public void setUserService(UserService userService) {
        this.userService = userService;
    }
    @ResponseBody//返回页面为字符串
    @RequestMapping("/select")
    public List all(){
        return userService.selectAll();
    }
}