SpringBoot(4)：整合Mybatis

1. 导入mybatis所需要的依赖

<!-- 引入 myBatis，这是 MyBatis官方提供的适配 Spring Boot的-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.0</version>
        </dependency>

2. 配置数据库连接信息

连接自己的数据库，并配置数据库的连接信息 

spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.url=jdbc:mysql://localhost:3306/Users?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

我们使用默认的数据源；先去测试一下连接是否成！

@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringbootDataApplicationTests {

    //DI注入数据源
    @Autowired
    DataSource dataSource;

    @Test
    public void contextLoads() throws SQLException {

        System.out.println("默认数据源:" + dataSource.getClass());
        //获得连接
        Connection connection = dataSource.getConnection();
        System.out.println("数据库连接："+connection);
        System.out.println("数据库连接地址：" + connection.getMetaData().getURL());
        connection.close();
        //关闭连接
        connection.close();
    }
}

3. 创建实体类

public class User {

    private int id;
    private String name;
    private String pwd;

    public User() {
    }

    public User(int id, String name, String pwd) {
        this.id = id;
        this.name = name;
        this.pwd = pwd;
    }

    public int getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPwd() {
        return pwd;
    }

    public void setPwd(String pwd) {
        this.pwd = pwd;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", pwd='" + pwd + '\'' +
                '}';
    }
}

4. 配置Mapper接口类

import com.qsh.springbootdata.pojo.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;
import java.util.List;

@Mapper  //表示这是一个Mapper接口
@Repository  //spring组件
public interface UserDao {

    //1.选择全部用户
    List<User> selectUser();
    //2.根据id选择用户
    User selectUserById(int id);
    //3.添加一个用户
    int addUser(User user);
    //4.修改一个用户
    int updateUser(User user);
    //5.根据id删除用户
    int deleteUser(int id);
}

5. Mapper映射文件

在resources下创建Mapper映射文件

<?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.qsh.springbootdata.dao.UserDao">

    <!--1.选择全部用户-->
    <select id="selectUser" resultType="User">
    select * from user
   </select>

    <!--2.根据id选择用户-->
    <select id="selectUserById" resultType="User">
    select * from user where id = #{id}
    </select>

    <!--3.添加一个用户-->
    <insert id="addUser" parameterType="User">
    insert into user (id,name,pwd) values (#{id},#{name},#{pwd})
    </insert>

    <!--4.修改一个用户-->
    <update id="updateUser" parameterType="User">
    update user set name=#{name},pwd=#{pwd} where id = #{id}
    </update>

    <!--5.根据id删除用户-->
    <delete id="deleteUser" parameterType="int">
    delete from user where id = #{id}
    </delete>

</mapper>

6. SpringBoot 整合

告诉springboot  myBatis的映射配置文件的位置

#连接mybatis  指定Mapper映射文件
mybatis.mapper-locations=classpath:mybatis/mapper/*.xml

#别名  注意：对应实体类的路径
mybatis.type-aliases-package=com.qsh.springbootdata.pojo

7. 编写controller

import com.qsh.springbootdata.dao.UserDao;
import com.qsh.springbootdata.pojo.User;
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 UserController {

    @Autowired
    UserDao userDao;

    //查询全部用户
    @GetMapping("/selectUser")
    public String selectUser() {
        List<User> users = userDao.selectUser();
        for (User user : users) {
            System.out.println(user);
        }
        return "ok";
    }

    //根据id选择用户
    @GetMapping("/selectUserById")
    public String selectUserById() {
        User user = userDao.selectUserById(1);
        System.out.println(user);
        return "ok";
    }

    //添加一个用户
    @GetMapping("/addUser")
    public String addUser() {
        userDao.addUser(new User(4, "赵四1", "456789"));
        return "ok";
    }

    //修改一个用户
    @GetMapping("/updateUser")
    public String updateUser() {
        userDao.updateUser(new User(4, "赵四2", "421319"));
        return "ok";
    }

    //根据id删除用户
    @GetMapping("/deleteUser")
    public String deleteUser() {
        userDao.deleteUser(4);
        return "ok";
    }

}

运行测试即可！！！

项目结构