first

README.md

@@ -1,10 +1,55 @@
 # mybatis-plus-join
+
 支持连表查询的[mybatis-plus](https://gitee.com/baomidou/mybatis-plus)
 
 ## 运行环境
-* mysql8 
-* jdk8 
+
+* mysql8
+* jdk8
 * mybatis-plus 3.4.2
 
 ## 使用方法
-* [参考测试类](https://gitee.com/best_handsome/mybatis-plus-join/blob/master/src/test/java/com/example/mp/MpJoinTest.java)
+
+### 使用
+
+* entity继承MyBaseEntity
+* mapper继承MyBaseMapper
+* service继承MyBaseService
+* serviceImpl继承MyBaseServiceImpl
+
+### MyLambdaQueryWrapper用法
+
+#### select(UserEntity::getId)  查询指定的字段,支持可变参数
+
+查询user表中的head_img,name和user_address表中的address,tel
+![image](https://gitee.com/best_handsome/mybatis-plus-join/raw/master/doc/select.png)
+对应sql  
+![image](https://gitee.com/best_handsome/mybatis-plus-join/raw/master/doc/selectSql.png)
+
+#### selectAll(UserEntity.class) 查询UserEntity全部字段
+
+查询user全部字段和user_address表中的address,tel
+![image](https://gitee.com/best_handsome/mybatis-plus-join/raw/master/doc/selectAll.png)
+对应sql  
+![image](https://gitee.com/best_handsome/mybatis-plus-join/raw/master/doc/selectAllSql.png)
+
+#### as(UserEntity::getHeadImg,UserDTO::getUserHeadImg)
+
+查询字段head_img as userHeadImg
+![image](https://gitee.com/best_handsome/mybatis-plus-join/raw/master/doc/selectAs.png)
+对应sql  
+![image](https://gitee.com/best_handsome/mybatis-plus-join/raw/master/doc/selectAsSql.png)
+
+#### 左连接 leftJoin(UserEntity::getId,UserAddressEntity::getUserId,right -> right)
+
+前连个参数是两个表的连接条件 -> user left join user_address on user.id = User_address.user_id  
+第三个参数是右表wrapper对象,可以继续使用,以上方法.
+
+#### 条件查询eq()
+
+![image](https://gitee.com/best_handsome/mybatis-plus-join/raw/master/doc/selectEq.png)
+对应sql  
+![image](https://gitee.com/best_handsome/mybatis-plus-join/raw/master/doc/selectEqSql.png)
+
+#### [参考测试类](https://gitee.com/best_handsome/mybatis-plus-join/blob/master/src/test/java/com/example/mp/MpJoinTest.java)
+

src/main/java/com/example/mp/business/dto/UserDTO.java

@@ -12,6 +12,8 @@ public class UserDTO {
     private String sex;
     /** user */
     private String headImg;
+    /** user */
+    private String userHeadImg;//同 headImg 别名测试
     /** user_address */
     private String tel;
     /** user_address */

src/main/java/com/example/mp/mybatis/plus/wrapper/MyJoinLambdaQueryWrapper.java

@@ -111,9 +111,9 @@ public class MyJoinLambdaQueryWrapper<T extends MyBaseEntity> extends MyAbstract
         setEntityClass(clazz);
         TableInfo info = TableInfoHelper.getTableInfo(getEntityClass());
         info.getFieldList().forEach(s ->
-                selectColumnList.add(new SelectColumn(this.rUid, s.getColumn(), s.getColumn()/*s.getProperty()*/, null)));
+                selectColumnList.add(new SelectColumn(this.rUid, s.getColumn(), null, null)));
         if (StringUtils.isNotBlank(info.getKeyColumn())) {
-            selectColumnList.add(new SelectColumn(this.rUid, info.getKeyColumn(),info.getKeyColumn()/* info.getKeyProperty()*/, null));
+            selectColumnList.add(new SelectColumn(this.rUid, info.getKeyColumn(), null, null));
         }
         return typedThis;
     }

src/test/java/com/example/mp/MpJoinTest.java

@@ -119,9 +119,14 @@ class MpJoinTest {
      * <p>
      * 自己去探索发现吧!
      */
+    @SuppressWarnings("all")
     @Test
     void test4() {
-        //todo
+        userMapper.selectJoinList(new MyLambdaQueryWrapper<UserEntity>()
+                        .as(UserEntity::getHeadImg,UserDTO::getUserHeadImg)
+                        .leftJoin(UserEntity::getId, UserAddressEntity::getUserId,
+                                right -> right.select(UserAddressEntity::getAddress, UserAddressEntity::getTel))
+                , UserDTO.class);
     }