Springboot结合MyBatis读取MySQL数据

目录

一.创建MyBatis程序

1.新建项目的子模块

2.添加为Maven项目

二.Mysql新建表

三.代码编写

1.分层架构创建

1.1创建controller、service、mapper、domain 包

1.2新建controller、service、mapper、domain 对应的Java 文件

1.3新建mapper 资源目录

1.4新建mapper 资源目录Java mapper 对应的XML 文件

2.配置数据库连接和MyBatis

2.1修改application.properties文件配置数据库

2.2MyBatis Mapper XML 文件基础知识

四.测试

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一.创建MyBatis程序

1.新建项目的子模块

2.添加为Maven项目

二.Mysql新建表

三.代码编写

1.分层架构创建

1.1创建controller、service、mapper、domain 包

1.2新建controller、service、mapper、domain 对应的Java 文件

1.3编写对应分层代码

@RestController
public class HelloController {
    @Autowired
    private UserService userService;

    @GetMapping("/hello")
    public List<User> hello()
    {
        return userService.selectAllUser();
    }
}

public class User {
    private Integer id;
    private String name;
    private Integer age;
    private Integer sex;
    public String createTime;

    public Integer getId() {return id;}
    public void setId(Integer id) {this.id = id;}
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    public Integer getSex() {
        return sex;
    }
    public void setSex(Integer sex) {
        this.sex = sex;
    }
    public String getCreateTime() {
        return createTime;
    }
    public void setCreateTime(String createTime) {
        this.createTime = createTime;
    }
}

@Mapper
public interface UserMapper {
//    @Select("select * from user")
    public List<User> selectAllUser();
}

@Service
public class UserService {
    @Autowired
    private UserMapper userMapper;

    public List<User> selectAllUser()
    {
        return userMapper.selectAllUser();
    }
}

1.4新建mapper 资源目录

1.5新建mapper 资源目录Java mapper 对应的XML 文件

2.配置数据库连接和MyBatis

2.1修改application.properties文件配置数据库

spring.application.name=mybatis

#配置数据库连接信息
spring.datasource.url=jdbc:mysql://localhost:3306/mybatis
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.username=root
spring.datasource.password=

#配置MyBatis的日志输出
mybatis.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl
#指定XML映射配置文件的位置
mybatis.mapper-locations=classpath:mapper/*.xml

2.2MyBatis Mapper XML 文件基础知识

<?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="org.example.mybatis.mapper.UserMapper">
    <resultMap id="UserResult" type="org.example.mybatis.domain.User">
        <id     property="id"   column="id"     />
        <result property="name" column="name"   />
        <result property="age"  column="age"   />
        <result property="sex"  column="sex"   />
        <result property="createTime"  column="create_time"   />
    </resultMap>

    <select id="selectAllUser" resultMap="UserResult">
        SELECT * FROM user
    </select>

</mapper>

四.测试