移除自定义别名

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yulichang 2021-11-17 12:16:35 +08:00
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# mybatis-plus-join
* 本页功能只能在1.2.0测试版中使用,最新版本 1.2.0.Beta5
* 点个Star支持一下吧 :)
QQ群:1022221898
## 使用方法
### 安装
- Maven
```xml
<dependency>
<groupId>com.github.yulichang</groupId>
<artifactId>mybatis-plus-join</artifactId>
<version>1.2.0.Beta5</version>
</dependency>
```
- Gradle
```
implementation group: 'com.github.yulichang', name: 'mybatis-plus-join', version: '1.2.0.Beta5'
```
或者clone代码到本地执行 mvn install, 再引入以上依赖
<br>
注意: mybatis plus version >= 3.4.0
<br>
### 使用
* mapper继承MPJBaseMapper
* service继承MPJBaseService (可选)
* serviceImpl继承MPJBaseServiceImpl (可选)
#### @EntityMapping@FieldMapping 注解
UserDO.java
```java
@Data
@TableName("user")
public class UserDO {
@TableId
private Integer id;
private Integer pid;//父id
/* 其他属性略 */
/**
* 查询上级 一对一
*/
@TableField(exist = false)
@EntityMapping(thisField = "pid", joinField = "id")
private UserDO pUser;
/**
* 查询下级 一对多
*/
@TableField(exist = false)
@EntityMapping(thisField = "id", joinField = "pid")
private List<UserDO> childUser;
/**
* 查询地址 (一对多)
*/
@TableField(exist = false)
@EntityMapping(thisField = "id", joinField = "userId")
private List<UserAddressDO> addressList;
/**
* 绑定字段 (一对多)
*/
@TableField(exist = false)
@FieldMapping(tag = UserDO.class, thisField = "id", joinField = "pid", select = "id")
private List<Integer> childIds;
}
```
使用
```java
/**
* 一对一,一对多关系映射查询
* 映射只对以Deep结尾有效比如 getByIdDeep listByIdsDeep 等
* 如果不需要关系映射就使用mybatis plus原生方法即可比如 getById listByIds 等
*
* 注意关系映射不会去关联查询而是执行多次单表查询对结果汇总后使用in语句查询,再对结果进行匹配)
*/
@SpringBootTest
class MappingTest {
@Resource
private UserMapper userMapper;
@Test
void test1() {
UserDO deep = userMapper.selectByIdDeep(2);
System.out.println(deep);
}
@Test
void test2() {
List<UserDO> list = userMapper.selectListDeep(Wrappers.emptyWrapper());
list.forEach(System.out::println);
}
@Test
void test3() {
Page<UserDO> page = userMapper.selectPageDeep(new Page<>(2, 2), Wrappers.emptyWrapper());
page.getRecords().forEach(System.out::println);
}
/**
* 更多方法请查阅 MPJDeepMapper 或者 MPJDeepService
* 使用方式与 mybatis plus 一致
*/
}
```
MPJMapping 说明:
* @EntityMapping / @FieldMapping tag 关联实体类
* @EntityMapping / @FieldMapping thisField 当前类关联对应的字段的属性名,可以不填,默认为当前类的主键
* @EntityMapping / @FieldMapping joinField 关联类对应的字段的属性名,可以不填,默认为关联类的主键
* @EntityMapping / @FieldMapping isThrowExp 一对一查询时,如果查询到多条记录是否抛出异常,true:抛出异常,false:获取列表第一条数据
*
更多功能请看代码注释 [EntityMapping](https://gitee.com/best_handsome/mybatis-plus-join/blob/master/src/main/java/com/github/yulichang/annotation/EntityMapping.java)
[FieldMapping](https://gitee.com/best_handsome/mybatis-plus-join/blob/master/src/main/java/com/github/yulichang/annotation/FieldMapping.java)