整合mybatis

整合包

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
</dependency>

配置文件:

application.properties

#整合mybatis
#别名
mybatis.type-aliases-package=com.ljm.pojo
#注册mapper
#classpath代表资源目录(resources)
mybatis.mapper-locations=classpath:mybatis/mapper/*.xml

.yml

spring:
  datasource:
    username: root
    password: my7shig69l>A
    url: jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC&useSSL=false&useUnicode=true&characterEncoding=UTF-8
    driver-class-name: com.mysql.cj.jdbc.Driver

 

各种层

 

 

mybatis配置:

xml

<?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">
<!--命名控件  绑定一个对应的Mapper接口-->
<mapper namespace="com.ljm.mapper.UserMapper">
<!--    <cache/>-->
<!--    useCache="true"-->
<!--    直接开启缓存*2-->
    <select id="queryUserList" resultType="user" >
        select * from mybatis.user
    </select>
</mapper>

mapper(DAO)

@Mapper   //这里不加mapper的话  启动类上面就得加@MapperScan("com.ljm.mapper")
@Repository 
public interface UserMapper {

    List<User> queryUserList();
}

//Repository用来表明该类是用来执行与数据库相关的操作（即dao对象），并支持自动处理数据库操作产生的异常
//@Mapper 表示这是一个mybatis的mapper类  注册  ,不加的话

service

import com.ljm.pojo.User;
import java.util.List;


public interface UserService {
    List<User> queryUserList();
}

//-------------------
import java.util.List;
@Service
public class UserServiceImpl implements UserService{

    @Autowired
    private UserMapper userMapper;

    @Override
    public List<User> queryUserList() {
        return userMapper.queryUserList();
    }
}

controller  调service层

@RestController
public class UserController {

    @Autowired
    private UserServiceImpl userService;  //实现类
//    private UserService userService;   //接口   两个测试都可以,有什么区别

    @GetMapping("/qu")
    public  List<User> queryUserList(){
        List<User> userList = userService.queryUserList();
        return userList;
    }
}