spring-boot-mybatis

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.7.5</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.lu</groupId>
    <artifactId>springboot-mybatis</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springboot-mybatis</name>
    <description>springboot-mybatis</description>
    <properties>
        <java.version>17</java.version>
    </properties>
    <dependencies>
        <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>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

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


        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

在yml中整合mybatis

spring:
  datasource:
    username: root
    password: root
    url: jdbc:mysql://localhost:3306/jz923?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
    driver-class-name: com.mysql.cj.jdbc.Driver

  #整合mybatis
mybatis:
  type-aliases-package: com.lu.pojo
  mapper-locations: classpath:mapper/*.xml

 在resources下面加入mapper目录新建usermapper.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">
<mapper namespace="com.lu.mapper.userMapper">
    <select id="getUsers" resultType="User">
        select * from user
    </select>

    <select id="getUser"  resultType="User" parameterType="int">
        select * from user where id =#{int}
    </select>
</mapper>

com.lu.controller.userController

package com.lu.controller;


import com.lu.mapper.userMapper;
import com.lu.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
    private userMapper userMapper;
    @GetMapping("/getUsers")
    public List<User> getUsers(){
        List<User> users = userMapper.getUsers();
        for (User user : users) {
            System.out.println(user);//后台查看我不看
        }
        return users;
    }
    @GetMapping("/getUser")
    public User getUser(int id){
        System.out.println("------------");
        User user = userMapper.getUser(id);
        System.out.println(user);
        return user;
    }

}

com.lu.mapper.userMapper

package com.lu.mapper;

import com.lu.pojo.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;

import java.util.List;
//这个注解表示这是mybatis的mapper类
@Mapper
@Repository
//@MapperScan("com.lu.mapper")另外一种写法,这个不放在这里要放在运行主类里面
public interface userMapper {
    List<User> getUsers();
    User getUser(int id);
//    int addUser(User user);
//    int deleteUser(int id);
//    int updateUser(User user);
}

此处省略实体类