Jpa实现逻辑删除

Spring Data 是个好东西，极大简化了后端dao的操作，只需要在 dao 接口写个 findByXXX 的方法就能自动实现按条件查询这个简直太爽了。但是在实际使用过程中，可能会遇到一个持久化逻辑删除的问题。那么问题来了。spring data jpa并不支持逻辑删除。那如何处理？

在互联网项目中，通常删除都不是物理删除，而是逻辑删除。

那么在展示数据的时候需要过滤掉已删除的数据。而@Where 注解可以说就是为此而设计的。

package org.hibernate.annotations;

import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.TYPE;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * Where clause to add to the element Entity or target entity of a collection.  The clause is written in SQL.
 * A common use case here is for soft-deletes.
 *
 * @author Emmanuel Bernard
 */
@Target({TYPE, METHOD, FIELD})
@Retention(RUNTIME)
public @interface Where {
    /**
     * The where-clause predicate.
     */
    String clause();
}

 这玩意儿乍一看很美好。但是实际不然。这样做将所有的删除方法都覆盖了。当我想要用到物理删除的时候。就不能用了。于是再次出发。寻找一种更加美妙的解决方案。终于让我找到了。话不多说。直接放码。

@NoRepositoryBean
public interface BaseDao<T extends BaseEntry, ID extends Serializable> extends PagingAndSortingRepository<T, ID> {
 
    @Override
    @Transactional(readOnly = true)
    @Query("select e from #{#entityName} e where e.deleted = false")
    List<T> findAll();
 
    @Override
    @Transactional(readOnly = true)
    @Query("select e from #{#entityName} e where e.id in ?1 and e.deleted = false")
    Iterable<T> findAll(Iterable<ID> ids);
 
    @Override
    @Transactional(readOnly = true)
    @Query("select e from #{#entityName} e where e.id = ?1 and e.deleted = false")
    T findOne(ID id);
 
    @Override
    @Transactional(readOnly = true)
    @Query("select count(e) from #{#entityName} e where e.deleted = false")
    long count();
 
    @Override
    @Transactional(readOnly = true)
    default boolean exists(ID id) {
        return findOne(id) != null;
    }
 
    @Query("update #{#entityName} e set e.deleted = true where e.id = ?1")
    @Transactional
    @Modifying
    void logicDelete(ID id);
 
    @Transactional
    default void logicDelete(T entity) {
        logicDelete((ID) entity.getId());
    }
 
    @Transactional
    default void logicDelete(Iterable<? extends T> entities) {
        entities.forEach(entity -> logicDelete((ID) entity.getId()));
    }
 
    @Query("update #{#entityName} e set e.deleted = true ")
    @Transactional
    @Modifying
    void logicDeleteAll();
}

BaseEntry代码如下：

    @Data
    @MappedSuperclass
    public class BaseEntry implements Serializable {
     
        private static final long serialVersionUID = 5966306766659220492L;
     
        @Id
        protected String id;
     
        @Temporal(TemporalType.TIMESTAMP)
        protected Date createdDate;
     
        protected String createdBy;
     
        @Temporal(TemporalType.TIMESTAMP)
        protected Date updatedDate;
     
        protected String updatedBy;
     
        protected Boolean deleted = false;
    }