## Mybatis-Plus

### LambdaUpdateWapper 配合泛型使用报错：com.baomidou.mybatisplus.core.exceptions.MybatisPlusException: can not find lambda cache for this property [xxx] of entity [com.xxx.si.fss.ssf.ass.entity.xxx]

```java
public interface CloseV1Service<T extends CloseStatefulEntity> {
    
    BaseMapper<T> getBaseMapper();

    default void action(CloseOperateVO operateVO){
        if (NullUtils.isEmpty(operateVO.getId())){
            throw new MyException(RestResponse.MSG.PARAM_VALUE_ERROR).setMsg("未发现指定操作对象id");
        }
        T closeEntity = getBaseMapper().selectById(operateVO.getId());
        if (closeEntity==null){
            throw new MyException(RestResponse.MSG.NO_DATA_EXISTS);
        }

        closeEntity.closeable(operateVO.getCloseAction());

        LambdaUpdateWrapper<T> lambdaUpdateWrapper = Wrappers.lambdaUpdate();
        lambdaUpdateWrapper
            .eq(T::getId,operateVO.getId()) //此处抛出异常
            .set(T::getCloseStatus, operateVO.getCloseAction().getStepState());

        getBaseMapper().update(null,lambdaUpdateWrapper);

    }
}
```

#### 原因：LambdaUpdateWrapper没有指定实体类类型

#### 解决方法：为LambdaUpdateWrapper对象指定实体类类型

```java
@Validated
public interface CloseV1Service<T extends CloseStatefulEntity> {
    Class<T> getTClass();

    BaseMapper<T> getBaseMapper();

    default void action(@NotNull(message = "操作VO对象不能为空") @Valid CloseOperateVO operateVO){
        if (NullUtils.isEmpty(operateVO.getId())){
            throw new MyException(RestResponse.MSG.PARAM_VALUE_ERROR).setMsg("未发现指定操作对象id");
        }
        T closeEntity = getBaseMapper().selectById(operateVO.getId());
        if (closeEntity==null){
            throw new MyException(RestResponse.MSG.NO_DATA_EXISTS);
        }

        closeEntity.closeable(operateVO.getCloseAction());
		//Wrappers.lambdaUpdate(getTClass()); 创建LambdaUpdate时指定实体类
        LambdaUpdateWrapper<T> lambdaUpdateWrapper = Wrappers.lambdaUpdate(getTClass());
        //或者lambdaUpdateWrapper.setEntityClass(getTClass());
        lambdaUpdateWrapper.eq(T::getId,operateVO.getId()).set(T::getCloseStatus, operateVO.getCloseAction().getStepState());

        getBaseMapper().update(null,lambdaUpdateWrapper);

    }
}
```



### LambdaUpdateWapper 配合泛型使用出现错误：java.lang.BootstrapMethodError: call site initialization exception

```java
public interface CloseV1Service<T extends CloseStatefulEntity & CloseV1able> {
    Class<T> getTClass();

    BaseMapper<T> getBaseMapper();

    default void action(@NotNull(message = "操作VO对象不能为空") @Valid CloseOperateVO operateVO){
        if (NullUtils.isEmpty(operateVO.getId())){
            throw new MyException(RestResponse.MSG.PARAM_VALUE_ERROR).setMsg("未发现指定操作对象id");
        }
        T closeEntity = getBaseMapper().selectById(operateVO.getId());
        if (closeEntity==null){
            throw new MyException(RestResponse.MSG.NO_DATA_EXISTS);
        }

        closeEntity.closeable(operateVO.getCloseAction());

        LambdaUpdateWrapper<T> lambdaUpdateWrapper = Wrappers.lambdaUpdate(getTClass());

        lambdaUpdateWrapper
            .eq(T::getId,operateVO.getId()) //此处抛出异常 因为CloseStatefulEntity存在getId()方法 而CloseV1able不存在
            .set(T::getCloseStatus, operateVO.getCloseAction().getStepState());

        getBaseMapper().update(null,lambdaUpdateWrapper);

    }
}
```

#### 原因：LambdaUpdateWrapper设置的泛型是因为有两个上界，LambdaUpdateWrapper使用方法引用时泛型的方法，这个方法只在泛型一个上界类中存在则抛出java.lang.BootstrapMethodError: call site initialization exception异常

#### 解决办法：在两个上界中都添加用到的方法或者只设置一个上界