spring boot使用mybatis

添加依赖

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.1.3</version>
</dependency>

添加数据库配置

server:
  port: 8081
spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/kira?characterEncoding=utf8&serverTimezone=UTC&useSSL=false
    username: root
    password: root
mybatis:
  configuration:
    map-underscore-to-camel-case: true

创建实体类

package com.kagarise.kira.entity;

import lombok.Data;

import java.io.Serializable;

@Data
public class User implements Serializable {
    private Integer userId;
    private String userName;
    private String userPwd;
}

创建动态SQL语句

package com.kagarise.kira.provider;

import com.kagarise.kira.entity.User;
import org.apache.ibatis.jdbc.SQL;

public class UserSqlProvider {
    public String insertUser(final User user) {
        return new SQL() {{
            INSERT_INTO("user");
//            INTO_COLUMNS("user_name", "user_pwd");
//            INTO_VALUES("#{userName}", "#{userPwd}");
            VALUES("user_name", "#{userName}");
            if (user.getUserPwd() != null) {
                VALUES("user_pwd", "#{userPwd}");
            } else {
                VALUES("user_pwd", "123456");
            }
        }}.toString();
    }

    public String updateUser(final User user) {
        return new SQL() {{
            UPDATE("user");
            SET("user_id=#{userId}");
            if (user.getUserName() != null)
                SET("user_name=#{userName}");
            if (user.getUserPwd() != null)
                SET("user_pwd=#{userPwd}");
            WHERE("user_id=#{userId}");
        }}.toString();
    }

    public String deleteUser() {
        return new SQL() {{
            DELETE_FROM("user");
            WHERE("user_id=#{userId}");
        }}.toString();
    }

    public String selectUser(final User user) {
        return new SQL() {{
            SELECT("*");
            FROM("user");
            if (user.getUserId() != 0)
                WHERE("user_id=#{userId}");
            if (user.getUserName() != null) {
                WHERE("user_name=#{userName}");
                if (user.getUserPwd() != null)
                    WHERE("user_pwd=#{userPwd}");
            }
        }}.toString();
    }
}

创建接口

package com.kagarise.kira.mapper;

import com.kagarise.kira.entity.User;
import com.kagarise.kira.provider.UserSqlProvider;
import org.apache.ibatis.annotations.*;

import java.util.List;

@Mapper
public interface UserMapper {

    @Select("SELECT * FROM user")
    List<User> findAll();

    //    @Select("SELECT * FROM user WHERE user_id = #{userId}")
    @SelectProvider(type = UserSqlProvider.class, method = "selectUser")
    User selectUser(User user);

    //    @Insert("INSERT INTO user (user_name, user_pwd) VALUES(#{userName}, #{userPwd})")
    @InsertProvider(type = UserSqlProvider.class, method = "insertUser")
    @Options(useGeneratedKeys = true, keyProperty = "userId", keyColumn = "user_id")
    boolean insertUser(User user);

    //    @Delete("DELETE FROM user WHERE user_id = #{userId}")
    @DeleteProvider(type = UserSqlProvider.class, method = "deleteUser")
    boolean deleteUser(int userId);

    //    @Update("UPDATE user SET user_name = #{userName},user_pwd = #{userPwd} WHERE user_id = #{userId}")
    @UpdateProvider(type = UserSqlProvider.class, method = "updateUser")
    boolean updateUser(User user);
}

创建控制类

package com.kagarise.kira.controller;

import com.kagarise.kira.entity.User;
import com.kagarise.kira.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
public class UserController {
    @Autowired
    UserMapper userMapper;

    @GetMapping("/users")
    public List<User> findAll() {
        return userMapper.findAll();
    }

    @GetMapping("/user")
    public User selectUser(User user) {
        return userMapper.selectUser(user);
    }

    @PostMapping("/user")
    public boolean insertUser(@RequestBody User user) {
        User nUser = new User();
        nUser.setUserName(user.getUserName());
        User sUser = userMapper.selectUser(nUser);
        if (sUser != null && sUser.getUserId() != 0)
            return false;
        return userMapper.insertUser(user);
    }

    @DeleteMapping("/user/{userId}")
    public boolean deleteUser(@PathVariable int userId) {
        return userMapper.deleteUser(userId);
    }

    @PatchMapping("/user")
    public boolean updateUser(@RequestBody User user) {
        return userMapper.updateUser(user);
    }

}