1、POM文件添加引用
<?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>2.5.6</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>MyBatisBoot</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>MyBatisBoot</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.4.3</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
<optional>true</optional>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<excludes>
<exclude>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</exclude>
</excludes>
</configuration>
</plugin>
</plugins>
</build>
</project>
2、配置文件(application.yml)
mybatis-plus:
# config-location: classpath:mybatis/mybatis-config.xml
mapper-locations: classpath:mybatis/mapper/*.xml
type-aliases-package: com.yas.entity
configuration:
lazy-loading-enabled: true
aggressive-lazy-loading: false
log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
map-underscore-to-camel-case: false
3、配置类(解决分页问题)
1 package com.yas.config;
2
3 import com.baomidou.mybatisplus.annotation.DbType;
4 import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
5 import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
6 import org.mybatis.spring.annotation.MapperScan;
7 import org.springframework.context.annotation.Bean;
8 import org.springframework.context.annotation.Configuration;
9
10 @Configuration
11 @MapperScan("com.yas.dao")
12 public class MybatisPlusConfig {
13
14 //配置mp分页插件
15 @Bean
16 public MybatisPlusInterceptor mybatisPlusInterceptor() {
17 MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
18 interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
19 return interceptor;
20 }
21 }
4、实体类(POJO)
1 package com.yas.entity;
2
3 import com.baomidou.mybatisplus.annotation.IdType;
4 import com.baomidou.mybatisplus.annotation.TableField;
5 import com.baomidou.mybatisplus.annotation.TableId;
6 import lombok.AllArgsConstructor;
7 import lombok.Data;
8 import lombok.NoArgsConstructor;
9 import lombok.ToString;
10
11 import java.util.Date;
12
13 @Data
14 @NoArgsConstructor
15 @AllArgsConstructor
16 @ToString
17 public class SysUser {
18 //指定主键生成方式为数据库自增
19 @TableId(type= IdType.AUTO)
20 private Integer id;
21 private String account;
22 private String username;
23
24 //查询时不反悔该字段的值
25 @TableField(select = false)
26 private String pwd;
27
28 private Date gmt_create;
29
30 //假如属性名与数据库表中的列名不同，可以在这里设置列名
31 @TableField(value = "gmt_modified")
32 private Date gmt_modified;
33
34 //这个属性不会进行映射
35 @TableField(exist = false)
36 private String otherProperty;
37 }
5、测试方法：
1 package com.yas;
2
3 import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
4 import com.baomidou.mybatisplus.core.conditions.update.UpdateWrapper;
5 import com.baomidou.mybatisplus.core.metadata.IPage;
6 import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
7 import com.yas.dao.SysUserPlusDAO;
8 import com.yas.entity.SysUser;
9 import org.junit.jupiter.api.Test;
10 import org.springframework.beans.factory.annotation.Autowired;
11 import org.springframework.boot.test.context.SpringBootTest;
12
13 import java.sql.Timestamp;
14 import java.util.*;
15
16 @SpringBootTest
17 public class MyBatisPlusTests {
18 @Autowired
19 SysUserPlusDAO sysUserPlusDAO;
20
21 //插入
22 @Test
23 void testInsert() {
24 SysUser user = new SysUser(null, "manager", "王羲之", "000000", new Date(), new Date(), null);
25 int result = sysUserPlusDAO.insert(user);
26 System.out.println(result);
27 System.out.println("主键回填：" + user.getId());
28 }
29
30 //根据id查询
31 @Test
32 void testSelectById() {
33 SysUser sysUser = sysUserPlusDAO.selectById(8);
34 System.out.println(sysUser);
35 }
36
37 //根据id更新
38 @Test
39 void testUpdateById() {
40 SysUser user = new SysUser();
41 user.setId(8);
42 user.setUsername("王献之");
43 int result = sysUserPlusDAO.updateById(user);
44 System.out.println(result);
45 }
46
47 //根据条件更新
48 @Test
49 void testUpdate() {
50 SysUser user = new SysUser();
51 user.setPwd("888888");
52
53 QueryWrapper<SysUser> wrapper = new QueryWrapper<>();
54 wrapper.eq("account", "manager");
55 int result = sysUserPlusDAO.update(user, wrapper);
56 System.out.println(result);
57 }
58
59
60 //根据条件更新2
61 @Test
62 void testUpdate2() {
63 UpdateWrapper<SysUser> wrapper = new UpdateWrapper<>();
64 wrapper.set("pwd", "666666").eq("account", "manager");
65 int result = sysUserPlusDAO.update(null, wrapper);
66 System.out.println(result);
67 }
68
69 //根据条件删除
70 @Test
71 void testDeleteById() {
72 int result = sysUserPlusDAO.deleteById(8);
73 System.out.println(result);
74 }
75
76 //根据map条件删除，多条件之间是and关系
77 @Test
78 void testDeleteByMap() {
79 Map<String, Object> map = new HashMap<>();
80 map.put("username", "王维");
81 map.put("pwd", "666666");
82 //根据map删除，多条件之间是 and 关系
83 int result = sysUserPlusDAO.deleteByMap(map);
84 System.out.println(result);
85 }
86
87 //使用条件删除
88 @Test
89 void testDeleteByWrapper() {
90 //用法一：
91 // QueryWrapper<SysUser> wrapper = new QueryWrapper<>();
92 // wrapper.eq("username","杜甫").eq("pwd","666666");
93
94 //用法二：(推荐)
95 SysUser user = new SysUser();
96 user.setUsername("李白");
97 user.setPwd("666666");
98 QueryWrapper<SysUser> wrapper = new QueryWrapper<>(user);
99
100 int result = sysUserPlusDAO.delete(wrapper);
101 System.out.println(result);
102 }
103
104 //根据id批量删除数据
105 @Test
106 void testDeleteByBatchIds() {
107 int result = sysUserPlusDAO.deleteBatchIds(Arrays.asList(9, 10));
108 System.out.println(result);
109 }
110
111 //查询 条件in
112 @Test
113 void testSelectBatchIds() {
114 List<SysUser> users = sysUserPlusDAO.selectBatchIds(Arrays.asList(1, 2, 3, 4, 5));
115 for (SysUser user : users) {
116 System.out.println(user);
117 }
118 }
119
120 //查询单条，返回结果最多只能有1条
121 @Test
122 void testSelectOne() {
123 SysUser user = new SysUser();
124 user.setId(1);
125 user.setAccount("admin");
126 user.setUsername("管理员");
127 QueryWrapper<SysUser> wrapper = new QueryWrapper<>(user);
128
129 SysUser user2 = sysUserPlusDAO.selectOne(wrapper);
130 System.out.println(user2);
131 }
132
133 @Test
134 void testSelectCount() {
135 QueryWrapper<SysUser> wrapper = new QueryWrapper<>();
136 wrapper.isNotNull("username");
137 int result = sysUserPlusDAO.selectCount(wrapper);
138 System.out.println(result);
139 }
140
141 @Test
142 void testSelectList() {
143 QueryWrapper<SysUser> wrapper = new QueryWrapper<>();
144 wrapper.isNotNull("username");
145 List<SysUser> users = sysUserPlusDAO.selectList(wrapper);
146 for (SysUser user : users) {
147 System.out.println(user);
148 }
149 }
150
151 @Test
152 void testSelectPage() {
153 Page<SysUser> page = new Page<>(1, 1);
154
155 QueryWrapper<SysUser> wrapper = new QueryWrapper<>();
156 wrapper.like("username", "C");
157 IPage<SysUser> iPage = sysUserPlusDAO.selectPage(page, wrapper);
158 System.out.println("数据总条数：" + iPage.getTotal());
159 System.out.println("总页数：" + iPage.getPages());
160 System.out.println("当前是第" + iPage.getCurrent() + "页");
161
162 List<SysUser> records = iPage.getRecords();
163 for (SysUser record : records) {
164 System.out.println(record);
165 }
166 }
167 }