springboot使用mybatis-plus

1.引入依赖

//mybatis-plus依赖

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.3.1.tmp</version>
</dependency>
// lombok插件依赖 详解用法：

   <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
2.建立实体类

@Data
@TableName("test")//对应数据库test表
public class Student {
    private String address;
    private String name;
}

3.建立test表 并添加数据
DROP TABLE IF EXISTS `test`;
CREATE TABLE `test`  (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL,
  `address` varchar(10) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL,
  `create_time` timestamp(0) DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 9 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;

INSERT INTO `test` VALUES (2, '张三2', '北京', '2019-09-10 12:22:23');
INSERT INTO `test` VALUES (3, '张三3', '北京', '2019-09-05 12:22:23');
INSERT INTO `test` VALUES (4, '李四1', '上海张三', '2019-09-06 12:22:23');
INSERT INTO `test` VALUES (5, '李四2', '上海', '2019-09-07 12:22:23');
INSERT INTO `test` VALUES (6, '李四3', '上海', '2019-09-12 12:22:23');
INSERT INTO `test` VALUES (7, '王二1', '广州', '2019-09-03 12:22:23');
INSERT INTO `test` VALUES (8, '王二2', '广州', '2019-09-04 12:22:23');
INSERT INTO `test` VALUES (9, '王二3', '广州', '2019-09-12 12:22:23');
INSERT INTO `test` VALUES (15, '校长', '上海', '2020-04-28 11:24:16');

SET FOREIGN_KEY_CHECKS = 1;

yml中添加任意一种数据库配置即可

 

 

4.controller 如下

 

 

 

 

 

其中的mapper

 

 

 

 

 

相应代码

/**
 * mybatis-plus 删
 * @return
 */
@RequestMapping("/deleteStudent")
@ResponseBody
public Object deleteStudent() {
    QueryWrapper<Student> queryWrapper = new QueryWrapper<>();
    queryWrapper.eq("id",1);//此处可以理解为查询id=1的Stusent
    mapper.delete(queryWrapper);
    return "delete";
}

/**
 * mybatis-plus 查
 * @return
 */
@RequestMapping("/updateStudent")
@ResponseBody
public Object updateStudent() {
    QueryWrapper<Student> queryWrapper = new QueryWrapper<>();
    queryWrapper.eq("id",2);
    Student student =new Student();
    student.setName("改姓名");
    mapper.update(student,queryWrapper);
    return "update";
}


/**
 * mybatis-plus 查
 * @return
 */
@RequestMapping("/getStudentList")
@ResponseBody
public Object getStudent() {
    QueryWrapper<Student> queryWrapper = new QueryWrapper<>();
    Student student=new Student();
    queryWrapper.like("address","北");//模糊查询字段为address 值为北的信息
    return mapper.selectList(queryWrapper);
}