SpringBoot+MyBatis+MySQL整合应用，将数据库显示到网页上，并可以CRUD（增删改查）

server.port=8088
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.url=jdbc:mysql://localhost:3306/springboot?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver


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

package com.example.mybatis;


public class User {
    private Integer ID;
    private String name;


    public User(Integer ID, String name) {
        this.ID = ID;
        this.name = name;
    }


    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;
    }


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

package com.example.mybatis;
import java.util.List;


public interface UserMapper {
    int insertUser(User user);
    int deleteUser(Integer id);
    User selectUser(Integer id);
    int updateUser(User user);
    List<User> selectAll();
}

<?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" >
<!--上面2行的是约束依赖，固定照抄就好-->
<!--下面的才是要自己编写的地方-->
<!--写mapper的配置文件第一步就是要写<mapper></mapper>标签-->
<!--<mapper></mapper>标签里包含着各个CURD操作的SQL语句-->
<mapper namespace="com.example.mybatis.UserMapper">
    <!--定义一个名为BaseResultMap的返回类型-->
    <resultMap id="BaseResultMap" type="com.example.mybatis.User">
        <id column="ID" property="ID" jdbcType="INTEGER"></id>
        <result column="name" property="name" jdbcType="VARCHAR"></result>


    </resultMap>


    <!--插入语句-->
    <!--id要与UserMapper文件中表示插入的函数名一致，parameterType表示函数的输入参数的类型-->
    <insert id="insertUser" parameterType="com.example.mybatis.User">
        insert into user(ID,name)values(#{ID,jdbcType=INTEGER},#{name,jdbcType=VARCHAR})/*SQL语句*/
    </insert>


    <!--删除语句-->
    <delete id="deleteUser" parameterType="java.lang.Integer">
        delete from user where ID =#{ID,jdbcType=INTEGER}
    </delete>


    <!--查找语句-->
    <!--resultMap表示函数返回的类型-->
    <select id="selectUser" parameterType="java.lang.Integer" resultMap="BaseResultMap">
        select * from user where ID = #{ID,jdbcType=INTEGER}
    </select>


    <!--查找语句-->
    <select id="selectAll" resultMap="BaseResultMap">
        select * from user
    </select>


    <!--修改语句-->
    <update id="updateUser" parameterType="com.example.mybatis.User">
        update user set name=#{name,jdbcType=VARCHAR} where ID=#{ID,jdbcType=INTEGER}
    </update>
</mapper>

package com.example.mybatis;
import java.util.List;
public interface UserService {
    int addUser(User user);
    int deleteUser(Integer id);
    User selectUser(Integer id);
    int updateUser(User user);
    List<User> findAll();
}

package com.example.mybatis;


import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;


import java.util.List;


@Service
public class UserServiceImpl implements UserService {
    @Autowired
    private UserMapper userMapper; //这里会报错，但并不影响


    @Override
    public int addUser(User user) {
        return userMapper.insertUser(user);
    }


    @Override
    public int deleteUser(Integer id) {
        return userMapper.deleteUser(id);
    }


    @Override
    public User selectUser(Integer id) {
        return userMapper.selectUser(id);
    }


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


    @Override
    public int updateUser(User user) {
        return userMapper.updateUser(user);
    }
}

package com.example.mybatis;


import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;


@SpringBootApplication
@MapperScan("com.example.mybatis")
public class MyBatisApplication {


    public static void main(String[] args) {
        SpringApplication.run(MyBatisApplication.class, args);
    }


}

package com.example.mybatis;


import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;


import java.util.List;
import java.util.Map;


@RestController
public class UserController {
    @Autowired
    private UserServiceImpl userService;


    @GetMapping(value = "/findAll")
    public List<User> findAll() {
        return userService.findAll();
    }


    @GetMapping(value = "add")
    public int addUser(){
        User u = new User(100,"ooo");
        int stat = userService.addUser(u);
        return stat;
    }


}