springboot 整合mybatis plus
简单介绍下 mybatis plus，mybatis plus（简称 MP）是一个 mybatis 的增强工具，在 MyBatis 的基础上只做增强不做改变，为简化开发、提高效率而生。
本文讲解使用 springboot 框架整合 mybatis plus，搭建开发环境，并介绍 mybatis plus 中一些常见的方法使用
1、创建项目
使用 eclipse、sts 编辑器或 idea 创建 springboot 项目，项目名称就使用 spring boot 和 mybatis plus 的开头英文字母命名吧，即 sbmp
创建项目完成后，添加需要使用的依赖，依赖 pom 文件如下
4.0.0
org.springframework.boot
spring-boot-starter-parent
2.1.13.RELEASE
com.sbmp
sbmp
0.0.1-SNAPSHOT
sbmp
Demo project for Spring Boot
1.8
3.1.1
org.springframework.boot
spring-boot-starter-web
org.springframework.boot
spring-boot-starter-test
test
com.baomidou
mybatis-plus-boot-starter
3.3.1
mysql
mysql-connector-java
org.projectlombok
lombok
org.springframework.boot
spring-boot-devtools
runtime
org.springframework.boot
spring-boot-maven-plugin
依赖添加完成后，配置 application.yml 文件
spring:
datasource:
url: jdbc:mysql://192.168.0.110:3306/sbmp?useUnicode=true&characterEncoding=utf8&autoReconnect=true&useSSL=false
driver-class-name: com.mysql.cj.jdbc.Driver
username: root
password: 123456
#mybatis plus 配置
mybatis-plus:
mapper-locations: classpath:mapper/*Mapper.xml
global-config:
banner: false
db-config:
id-type: uuid
table-underline: true
configuration:
call-setters-on-nulls: true
#sql打印
logging:
level:
com.sbmp.mapper: debug数据库的配置，和 sql打印的配置就不多说了
mybatis plus 的配置
mapper-locations 指定 mybatis xml文件的位置
global-config: banner: false 不显示 mybatis plus 的 banner
global-config: db-config: id-type: uuid 全局默认主键类型为 uuid
global-config: db-config: table-underline: true 表名是否使用驼峰转下划线命名,只对表名生效
configuration: call-setters-on-nulls: true 返回查询语句中某些字段值是null的
yml文件配置完成后，在 resources 目录下创建 mapper 文件夹，用来放 xml 文件
项目创建完成后，结构如下
springboot 项目启动类
配置 mapper 扫描包路径
package com.sbmp;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@MapperScan("com.sbmp.mapper")
@SpringBootApplication
public class SbmpApplication {
public static void main(String[] args) {
SpringApplication.run(SbmpApplication.class, args);
}
}
2、数据库建表
建表 sql 如下
人物表
DROP TABLE IF EXISTS `sbmp_user`;
CREATE TABLE `sbmp_user` (
`user_id` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
`user_name` varchar(30) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
`nick_name` varchar(30) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
`department_id` int(5) NULL DEFAULT NULL,
`create_date` datetime(0) NULL DEFAULT NULL,
`del_flag` char(1) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
PRIMARY KEY (`user_id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
-- ----------------------------
-- Records of sbmp_user
-- ----------------------------
INSERT INTO `sbmp_user` VALUES ('01061280e061419b98069b8efd6be804', '周通', '小霸王', 5, '2020-08-18 07:08:46', '0');
INSERT INTO `sbmp_user` VALUES ('02e8a27163984dca94876ec7d85f0389', '彭玘', '天目将', 5, '2020-08-18 07:08:46', '0');
INSERT INTO `sbmp_user` VALUES ('123d2bddd5d3465c9ab531d183a7600b', '杨志', '青面兽', 4, '2020-08-12 14:58:09', '0');
INSERT INTO `sbmp_user` VALUES ('15f578aac45846a7a0a0eb05f9a70eb4', '呼延灼', '双鞭', 3, '2020-08-11 14:54:20', '0');
INSERT INTO `sbmp_user` VALUES ('16226f66f6e943b1836452ca6cc95076', '孙立', '病尉迟', 5, '2020-08-18 07:04:56', '0');
INSERT INTO `sbmp_user` VALUES ('17ed7e281c3c43d2bb3dbcf1a4c19139', '刘唐', '赤发鬼', 6, '2020-08-18 07:08:46', '0');
INSERT INTO `sbmp_user` VALUES ('24cb471e3ed14d069fd725c673d6a18c', '解珍', '两头蛇', 6, '2020-08-18 15:20:41', '0');
INSERT INTO `sbmp_user` VALUES ('2fef80719549413eaaf09b4f6e3e097b', '武松', '行者', 6, '2020-08-18 07:08:46', '0');
INSERT INTO `sbmp_user` VALUES ('37d675c8670e4908897437fed4030a98', '黄信', '镇三山', 5, '2020-08-18 07:03:16', '0');
INSERT INTO `sbmp_user` VALUES ('394f70197cf34bd5869469f6313c7277', '穆弘', '没遮拦', 4, '2020-08-18 07:02:07', '0');
INSERT INTO `sbmp_user` VALUES ('39b78c88fd5d43daa8bd5da80b5b223d', '鲁智深', '花和尚', 6, '2020-08-18 07:08:46', '0');
INSERT INTO `sbmp_user` VALUES ('3ff9a386eb8b419784cf1136b430636d', '杨林', '锦豹子', 5, '2020-08-18 07:08:46', '0');
INSERT INTO `sbmp_user` VALUES ('4427b546e58a493990f4633270a09a61', '董平', '双枪将', 3, '2020-08-18 06:55:51', '0');
INSERT INTO `sbmp_user` VALUES ('469602c0533743c081a0a49042a61d57', '雷横', '插翅虎', 6, '2020-08-18 07:08:46', '0');
INSERT INTO `sbmp_user` VALUES ('4ec8fe199e104492bd5d9e4f6f2fc06e', '张清', '没羽箭', 4, '2020-08-13 07:00:31', '0');
INSERT INTO `sbmp_user` VALUES ('538e80dc2ef14e94852112da14f42508', '陈达', '跳涧虎', 5, '2020-08-18 07:08:46', '0');
INSERT INTO `sbmp_user` VALUES ('5b1e615d92e34471ba18b7d6b34d112e', '杨春', '白花蛇', 5, '2020-08-18 07:08:46', '0');
INSERT INTO `sbmp_user` VALUES ('65bce3c9ae884a18952cbe5e429071c0', '李忠', '打虎将', 7, '2020-08-18 15:21:20', '0');
INSERT INTO `sbmp_user` VALUES ('703f218227574ba29aa8ac8c49c967aa', '秦明', '霹雳火', 3, '2020-08-11 14:53:34', '0');
INSERT INTO `sbmp_user` VALUES ('744bf74937384a96a5a44be053da6d02', '石秀', '拼命三郎', 6, '2020-08-16 15:20:31', '0');
INSERT INTO `sbmp_user` VALUES ('7b3c7296d12b4700936cca6440ca60bf', '燕青', '浪子', 6, '2020-08-15 15:20:24', '0');
INSERT INTO `sbmp_user` VALUES ('7c2052f30ac741f7bf4e5effee164965', '马麟', '铁笛仙', 5, '2020-08-18 07:08:46', '0');
INSERT INTO `sbmp_user` VALUES ('80d4eda453f943a5aa60a1642dae6fbc', '吴用', '智多星', 2, '2020-08-10 14:49:42', '0');
INSERT INTO `sbmp_user` VALUES ('8a7436a6f5884cc5a59908ec73060d2a', '燕顺', '锦毛虎', 5, '2020-08-18 07:08:46', '0');
INSERT INTO `sbmp_user` VALUES ('8d3396996aa04cb1bb71ce17cb2624c4', '邓飞', '火眼狻猊', 5, '2020-08-18 07:08:46', '0');
INSERT INTO `sbmp_user` VALUES ('936eca00e3ba47528341f3ffd2e99363', '欧鹏', '摩云金翅', 5, '2020-08-18 07:08:46', '0');
INSERT INTO `sbmp_user` VALUES ('975afbff93a443839c9cb036c2a2d3a2', '李逵', '黑旋风', 6, '2020-08-15 15:20:28', '0');
INSERT INTO `sbmp_user` VALUES ('9d36acdc42c149cd88c323e92bb1458f', '卢俊义', '玉麒麟', 1, '2020-08-09 14:48:36', '0');
INSERT INTO `sbmp_user` VALUES ('a16cf2ef4030405cbc8a2f774eeba504', '魏定国', '神火将', 5, '2020-08-18 07:08:46', '0');
INSERT INTO `sbmp_user` VALUES ('a7f5684c7906485cbd8fd8e623192bfc', '关胜', '大刀', 3, '2020-08-11 14:51:31', '0');
INSERT INTO `sbmp_user` VALUES ('aabed1004c4f44ddb5f01b48275fbb57', '林冲', '豹子头', 3, '2020-08-11 14:53:04', '0');
INSERT INTO `sbmp_user` VALUES ('adbec35c5e664c47ad24eafd15e832c5', '单廷', '圣水将', 5, '2020-08-18 07:08:46', '0');
INSERT INTO `sbmp_user` VALUES ('b799d4f3e4a842d19b2bb0f75c634f4f', '索超', '急先锋', 4, '2020-08-12 06:58:53', '0');
INSERT INTO `sbmp_user` VALUES ('b8ce96e985974f92a29f12c91bb9a70d', '史进', '九纹龙', 4, '2020-08-18 07:01:42', '0');
INSERT INTO `sbmp_user` VALUES ('bcf6f9425beb4372b1d9eb759668d394', '公孙胜', '入云龙', 2, '2020-08-10 14:50:37', '0');
INSERT INTO `sbmp_user` VALUES ('c2155bd6cb854afd9e8653c30143c97a', '韩滔', '百胜将', 5, '2020-08-18 07:08:46', '0');
INSERT INTO `sbmp_user` VALUES ('c70b18768f1a4368a2bcf5a7d0c6d0c7', '解宝', '双尾蝎', 6, '2020-08-17 15:20:38', '0');
INSERT INTO `sbmp_user` VALUES ('c9b00a4ad55b4e4bb1009ee0907bd777', '宣赞', '丑郡马', 5, '2020-08-18 07:08:46', '0');
INSERT INTO `sbmp_user` VALUES ('e9cf6112649944348113986e3026553b', '花荣', '小李广', 4, '2020-08-12 14:56:41', '0');
INSERT INTO `sbmp_user` VALUES ('f138761dd1e74b849c6c76944cd66b86', '朱仝', '美髯公', 4, '2020-08-18 07:01:08', '0');
INSERT INTO `sbmp_user` VALUES ('f9cbf631fdd74ad492179a1e920ea757', '徐宁', '金枪手', 4, '2020-08-12 14:57:24', '0');
INSERT INTO `sbmp_user` VALUES ('fc19642ee7e34353908af012d20e6f11', '杨雄', '病关索', 6, '2020-08-17 15:20:35', '0');
INSERT INTO `sbmp_user` VALUES ('fd4720f79ea04b348d8d650b619a0e23', '宋江', '呼保义', 1, '2020-08-08 14:47:44', '0');
INSERT INTO `sbmp_user` VALUES ('ff98a17f60544eeaa7a37a009ae2ab40', '郝思文', '井木犴', 5, '2020-08-18 07:08:46', '0');
SET FOREIGN_KEY_CHECKS = 1;
部门表
DROP TABLE IF EXISTS `sbmp_department`;
CREATE TABLE `sbmp_department` (
`department_id` int(11) NULL DEFAULT NULL,
`department_name` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
-- ----------------------------
-- Records of sbmp_department
-- ----------------------------
INSERT INTO `sbmp_department` VALUES (1, '梁山泊总兵都头领');
INSERT INTO `sbmp_department` VALUES (2, '梁山泊掌管机密军师');
INSERT INTO `sbmp_department` VALUES (3, '马军五虎将');
INSERT INTO `sbmp_department` VALUES (4, '马军八骠骑兼先锋使');
INSERT INTO `sbmp_department` VALUES (5, '马军小彪将兼远探出哨头领');
INSERT INTO `sbmp_department` VALUES (6, '步军头领');
INSERT INTO `sbmp_department` VALUES (7, '步军将校');
INSERT INTO `sbmp_department` VALUES (8, '梁山泊四寨水军头领');
INSERT INTO `sbmp_department` VALUES (9, '梁山泊四店打听声息邀接来宾头领');
INSERT INTO `sbmp_department` VALUES (10, '梁山泊总探声息头领');
INSERT INTO `sbmp_department` VALUES (11, '梁山泊军中走报机密步军头领');
INSERT INTO `sbmp_department` VALUES (12, '守护中军马军骁将');
INSERT INTO `sbmp_department` VALUES (13, '守护中军步军骁将');
INSERT INTO `sbmp_department` VALUES (14, '梁山泊专掌行刑刽子');
INSERT INTO `sbmp_department` VALUES (15, '专掌三军内探事马军头领');
INSERT INTO `sbmp_department` VALUES (16, '梁山泊一同参赞军务头领');
INSERT INTO `sbmp_department` VALUES (17, '梁山泊掌管监造诸事头领');
INSERT INTO `sbmp_department` VALUES (18, '掌管行文走徼调兵遣将');
SET FOREIGN_KEY_CHECKS = 1;
3、创建 bean、mapper、service、controller 层
这里为了演示，笔者以水浒传里的人物为数据，进行演示
创建User实体类
当表名与实体类名不一致时，可以通过注解@TableName进行映射
注解@TableId 可指定主键字段，设置主键类型，如 uuid 或 主键自增
package com.sbmp.bean;
import java.util.Date;
import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.Data;
@TableName("sbmp_user")
@Data
public class User {
@TableId(type = IdType.ASSIGN_UUID)
private String userId;
private String userName;
private String nickName;
private Integer departmentId;
private Date createDate;
private String delFlag;
}
创建 Department 实体类
package com.sbmp.bean;
import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.Data;
@TableName("sbmp_department")
@Data
public class Department {
@TableId(type = IdType.AUTO)
private Integer departmentId;
private String departmentName;
}
创建 mapper 层
UserMapper
package com.sbmp.mapper;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.sbmp.bean.User;
public interface UserMapper extends BaseMapper{
} DepartmentMapper
package com.sbmp.mapper;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.sbmp.bean.Department;
public interface DepartmentMapper extends BaseMapper{
}
创建 service 层
UserService
package com.sbmp.service;
import com.baomidou.mybatisplus.extension.service.IService;
import com.sbmp.bean.User;
public interface UserService extends IService{
}
DepartmentService
package com.sbmp.service;
import com.baomidou.mybatisplus.extension.service.IService;
import com.sbmp.bean.Department;
public interface DepartmentService extends IService{
}
创建 service 实现层
UserServiceImpl
package com.sbmp.service.impl;
import org.springframework.stereotype.Service;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.sbmp.bean.User;
import com.sbmp.mapper.UserMapper;
import com.sbmp.service.UserService;
@Service
public class UserServiceImpl extends ServiceImpl implements UserService{
}
DepartmentServiceImpl
package com.sbmp.service.impl;
import org.springframework.stereotype.Service;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.sbmp.bean.Department;
import com.sbmp.mapper.DepartmentMapper;
import com.sbmp.service.DepartmentService;
@Service
public class DepartmentServiceImpl extends ServiceImpl implements DepartmentService {
}
创建 controller 层
package com.sbmp.controller;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.sbmp.bean.Department;
import com.sbmp.service.DepartmentService;
@RequestMapping("/department")
@RestController
public class DepartmentController {
@Autowired
private DepartmentService departmentService;
@RequestMapping("/list")
public Object list() {
List list = departmentService.list();
return list;
}
}
以上各层创建完成后，springboot 整合mybatis plus 环境基本搭建完成
4、测试
浏览器访问：http://localhost:8080/department/list
效果如下图
返回这个结果，说明搭建成功
初次使用 mybatis plus 的人可能会有疑问，没写sql，为什么能查出全部部门表数据，这就是mybatis plus的强大之处，它已经封装了基本的sql，后面笔者慢慢介绍
5、自定义 sql
除了使用 mybatis plus 封装好的 sql 外，mybatis plus 还可以像使用 mybatis 一样，在xml 中写sql，下面讲解如何实现自定义sql
（1）、新建实体类 UserDetail
用来映射关联后的数据
package com.sbmp.bean;
import lombok.Data;
@Data
public class UserDetail {
private String userName;
private String nickName;
private String departmentName;
}
（2）、UserMapper 中添加新的方法
package com.sbmp.mapper;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.sbmp.bean.User;
import com.sbmp.bean.UserDetail;
public interface UserMapper extends BaseMapper{
UserDetail getUserDetail(String id);
} （3）UserMapper.xml 中写对应的 sql 语句
（4）、修改 UserService及 UserService实现层
package com.sbmp.service;
import com.baomidou.mybatisplus.extension.service.IService;
import com.sbmp.bean.User;
import com.sbmp.bean.UserDetail;
public interface UserService extends IService{
UserDetail getUserDetail(String id);
}
UserService实现层
package com.sbmp.service.impl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.sbmp.bean.User;
import com.sbmp.bean.UserDetail;
import com.sbmp.mapper.UserMapper;
import com.sbmp.service.UserService;
@Service
public class UserServiceImpl extends ServiceImpl implements UserService{
@Autowired
private UserMapper userMapper;
@Override
public UserDetail getUserDetail(String id) {
return userMapper.getUserDetail(id);
}
}
（5）、UserController
package com.sbmp.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.sbmp.service.UserService;
@RequestMapping("/user")
@RestController
public class UserController {
@Autowired
private UserService userService;
@RequestMapping("/get/{id}")
public Object getUserDetail(@PathVariable("id")String id) {
return userService.getUserDetail(id);
}
}
（6）测试
浏览器访问：http://localhost:8080/user/get/bcf6f9425beb4372b1d9eb759668d394
效果如下
至此， springboot 框架整合 mybatis plus，搭建开发环境完成
关于 mybatis plus 的自带 sql 实现增删改查，后续介绍