SpringBoot整合Mybatisplus3.x之CRUD(一)

• pom.xml

   <dependencies>
           <dependency>
               <groupId>org.springframework.boot</groupId>
               <artifactId>spring-boot-starter</artifactId>
           </dependency>
           <dependency>
               <groupId>org.springframework.boot</groupId>
               <artifactId>spring-boot-starter-test</artifactId>
               <scope>test</scope>
           </dependency>
           <dependency>
               <groupId>org.projectlombok</groupId>
               <artifactId>lombok</artifactId>
               <optional>true</optional>
           </dependency>
           <dependency>
               <groupId>com.baomidou</groupId>
               <artifactId>mybatis-plus-boot-starter</artifactId>
               <version>3.2.0</version>
           </dependency>
           <dependency>
               <groupId>com.h2database</groupId>
               <artifactId>h2</artifactId>
               <scope>runtime</scope>
           </dependency>
           <dependency>
               <groupId>p6spy</groupId>
               <artifactId>p6spy</artifactId>
           </dependency>
       </dependencies>
   ​
       <build>
           <plugins>
               <plugin>
                   <groupId>org.springframework.boot</groupId>
                   <artifactId>spring-boot-maven-plugin</artifactId>
               </plugin>
           </plugins>
       </build>

• application.yml

  # DataSource Config
  spring:
    datasource:
      driver-class-name: org.h2.Driver
      url: jdbc:h2:tcp://192.168.180.115:19200/~/mem/test
      username: root
      password: test
  ​
  # Logger Config
  logging:
    level:
      com.mp.crud: debug

  ​

• dao层

  public interface UserMapper extends BaseMapper<User> {
  ​
  }

• 实体类

   @Data
   @Accessors(chain = true)
   @TableName("user")
   public class User {
   ​
       private Long id;
       private String name;
       private Integer age;
       private String email;
   ​
       @TableField(exist = false)
       private Integer count;
   }

  ​

• 配置类

   @Configuration
   @MapperScan("com.mp.crud.mapper")
   public class MybatisPlusConfig {
   ​
   }
   ​

• 测试类

   @SpringBootTest
   @RunWith(SpringRunner.class)
   class CrudApplicationTests {
   ​
       @Resource
       private UserMapper mapper;
   ​
       @Test
       public void aInsert() {
           User user = new User();
           user.setName("小羊");
           user.setAge(3);
           user.setEmail("abc@mp.com");
           assertThat(mapper.insert(user)).isGreaterThan(0);
           // 成功直接拿会写的 ID
           assertThat(user.getId()).isNotNull();
       }
   ​
   ​
       @Test
       public void bDelete() {
           assertThat(mapper.deleteById(3L)).isGreaterThan(0);
           assertThat(mapper.delete(new QueryWrapper<User>()
                   .lambda().eq(User::getName, "Sandy"))).isGreaterThan(0);
       }
   ​
   ​
       @Test
       public void cUpdate() {
           //UPDATE user SET email=? WHERE id=?
           assertThat(mapper.updateById(new User().setId(1L).setEmail("ab@c.c"))).isGreaterThan(0);
           //UPDATE user SET name=?, age=? WHERE (id = ?)
           assertThat(
                   mapper.update(
                           new User().setName("mp"),
                           Wrappers.<User>lambdaUpdate()
                                   .set(User::getAge, 3)
                                   .eq(User::getId, 2)
                   )
           ).isGreaterThan(0);
           User user = mapper.selectById(2);
           assertThat(user.getAge()).isEqualTo(3);
           assertThat(user.getName()).isEqualTo("mp");
   ​
           mapper.update(
                   null,
                   Wrappers.<User>lambdaUpdate().set(User::getEmail, null).eq(User::getId, 2)
           );
           assertThat(mapper.selectById(1).getEmail()).isEqualTo("ab@c.c");
           user = mapper.selectById(2);
           assertThat(user.getEmail()).isNull();
           assertThat(user.getName()).isEqualTo("mp");
   ​
           mapper.update(
                   new User().setEmail("miemie@baomidou.com"),
                   new QueryWrapper<User>()
                           .lambda().eq(User::getId, 2)
           );
           user = mapper.selectById(2);
           assertThat(user.getEmail()).isEqualTo("miemie@baomidou.com");
   ​
           mapper.update(
                   new User().setEmail("miemie2@baomidou.com"),
                   Wrappers.<User>lambdaUpdate()
                           .set(User::getAge, null)
                           .eq(User::getId, 2)
           );
           user = mapper.selectById(2);
           assertThat(user.getEmail()).isEqualTo("miemie2@baomidou.com");
           assertThat(user.getAge()).isNull();
       }
   ​
   ​
       @Test
       public void dSelect() {
           mapper.insert(
                   new User().setId(10086L)
                           .setName("miemie")
                           .setEmail("miemie@baomidou.com")
                           .setAge(3));
           assertThat(mapper.selectById(10086L).getEmail()).isEqualTo("miemie@baomidou.com");
           User user = mapper.selectOne(new QueryWrapper<User>().lambda().eq(User::getId, 10086));
           assertThat(user.getName()).isEqualTo("miemie");
           assertThat(user.getAge()).isEqualTo(3);
   ​
           List<User> users = mapper.selectList(Wrappers.<User>lambdaQuery().select(User::getId));
           System.out.println(users);
   ​
           mapper.selectList(Wrappers.<User>lambdaQuery().select(User::getId))
                   .forEach(x -> {
                       assertThat(x.getId()).isNotNull();
                       assertThat(x.getEmail()).isNull();
                       assertThat(x.getName()).isNull();
                       assertThat(x.getAge()).isNull();
                   });
           mapper.selectList(new QueryWrapper<User>().select("id", "name"))
                   .forEach(x -> {
                       assertThat(x.getId()).isNotNull();
                       assertThat(x.getEmail()).isNull();
                       assertThat(x.getName()).isNotNull();
                       assertThat(x.getAge()).isNull();
                   });
       }
   ​
       @Test
       public void orderBy() {
           List<User> users = mapper.selectList(Wrappers.<User>query().orderByAsc("age"));
           System.out.println(users);
           //assertThat(users).isNotEmpty();
       }
   ​
       @Test
       public void selectMaps() {
           List<Map<String, Object>> mapList = mapper.selectMaps(Wrappers.<User>query().orderByAsc("age"));
           assertThat(mapList).isNotEmpty();
           assertThat(mapList.get(0)).isNotEmpty();
           //{ID=1189005852158324737, EMAIL=abc@mp.com, NAME=小羊, AGE=3}
           System.out.println(mapList.get(0));
       }
   ​
       @Test
       public void selectMapsPage() {
           IPage<Map<String, Object>> page = mapper.selectMapsPage(new Page<>(1, 5), Wrappers.<User>query().orderByAsc("age"));
           assertThat(page).isNotNull();
           assertThat(page.getRecords()).isNotEmpty();
           assertThat(page.getRecords().get(0)).isNotEmpty();
       }
   ​
       @Test
       public void orderByLambda() {
           //SELECT id,name,email,age FROM user ORDER BY age ASC
           List<User> users = mapper.selectList(Wrappers.<User>lambdaQuery().orderByAsc(User::getAge));
           List<User>  users1 = mapper.selectList(Wrappers.<User>query().orderByAsc("age"));
           System.out.println(users1);
           //assertThat(users).isNotEmpty();
       }
   ​
       @Test
       public void testSelectMaxId() {
           // SELECT max(id) as id FROM user
           QueryWrapper<User> wrapper = new QueryWrapper<>();
           wrapper.select("max(id) as id");
           //User(id=1189005852158324737, name=null, age=null, email=null, count=null)
           User user = mapper.selectOne(wrapper);
           System.out.println(user);
           System.out.println("maxId=" + user.getId());
           List<User> users = mapper.selectList(Wrappers.<User>lambdaQuery().orderByDesc(User::getId));
           Assert.assertEquals(user.getId().longValue(), users.get(0).getId().longValue());
       }
   ​
       @Test
       public void testGroup() {
           QueryWrapper<User> wrapper = new QueryWrapper<>();
           wrapper.select("age, count(*)")
                   .groupBy("age");
           List<Map<String, Object>> maplist = mapper.selectMaps(wrapper);
           for (Map<String, Object> mp : maplist) {
               System.out.println(mp);
           }
           /**
            * lambdaQueryWrapper groupBy orderBy
            */
           LambdaQueryWrapper<User> lambdaQueryWrapper = new QueryWrapper<User>().lambda()
                   .select(User::getAge)
                   .groupBy(User::getAge)
                   .orderByAsc(User::getAge);
           for (User user : mapper.selectList(lambdaQueryWrapper)) {
               System.out.println(user);
           }
       }
   ​
       @Test
       public void testTableFieldExistFalse(){
           QueryWrapper<User> wrapper = new QueryWrapper<>();
           wrapper.select("age, count(age) as count")
                   .groupBy("age");
           List<User> list = mapper.selectList(wrapper);
           list.forEach(System.out::println);
           list.forEach(x->{
               Assert.assertNull(x.getId());
               Assert.assertNotNull(x.getAge());
               Assert.assertNotNull(x.getCount());
           });
           mapper.insert(
                   new User().setId(10088L)
                           .setName("miemie")
                           .setEmail("miemie@baomidou.com")
                           .setAge(3));
           User miemie = mapper.selectById(10088L);
           Assert.assertNotNull(miemie);
   ​
       }
   ​
   }
   ​

• 测试结果（我处只运行了部分的测试方法）