Spring数据JPA Spel-@Query问题

Question

我无法让SPEL和Spring data jpa正常工作

以下是我的仓库

package eg.repository;
public interface MyEntityRepository extends JpaRepository<MyEntity, Long>,JpaSpecificationExecutor<MyEntity> {

    @Query("SELECT e FROM eg.domain.MyEntity e " +
            "WHERE e.title = :#{#filter.title}"
    )
    Page<MyEntity> list1(@Param("filter") MyFilter filter,Pageable pageable);
}

过滤元件

package eg.service;

import org.springframework.stereotype.Component;

@Component("filter")
public class MyFilter {

    public String titleFilter() {
        return "%title%";
    }
    private String title = "title title1";
    public Long[] idFilter() {
        return new Long[] {
                1L, 2L
        };
    }
}

以下是MyEntity

package eg.domain;
@Entity
public class MyEntity implements Serializable {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(name = "title")
    private String title;
    ......
}

主类

LOG.info("Application initialized " + annotationConfigApplicationContext);
        MyEntityRepository myEntityRepository =
                    (MyEntityRepository) annotationConfigApplicationContext.getBean(MyEntityRepository.class);
        MyFilter filter = annotationConfigApplicationContext.getBean(MyFilter.class);
        PageRequest pageRequest = new PageRequest(0, 5);
        Page<MyEntity> page = myEntityRepository.list1(filter,pageRequest);
        List<MyEntity> entities= page.getContent();
        for(MyEntity entity: entities){
            System.out.println(entity.getId() + " TITLE " +  entity.getTitle());
        }

下面是我得到的错误

Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'myEntityRepository': FactoryBean threw exception on object creation; nested exception is java.lang.IllegalStateException: Using named parameters for method public abstract org.springframework.data.domain.Page eg.repository.MyEntityRepository.list1(eg.service.MyFilter,org.springframework.data.domain.Pageable) but parameter 'filter' not found in annotated query 'SELECT e FROM eg.domain.MyEntity e WHERE e.title = :#{#filter.title}'!

Answer 1

通过SpEL访问传递的参数对象的值通常非常有用，甚至你的语法也似乎是正确的。

也许再和Spring Data JPA和SpEL进行一次比较

你真的确定错误消息完全属于你发布的代码吗？你后来调整过了吗？我把它简化了一点，这是一个有效的测试用例示例。

实体：

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

@Entity
public class MyEntity {

    @Id
    @GeneratedValue
    private Long id;

    private String title;

    public MyEntity(String title) {
        this.title = title;
    }

    public Long getId() {
        return id;
    }

    public String getTitle() {
        return title;
    }

}

存储库：

package com.example.repository;

import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.query.Param;

import com.example.model.MyEntity;
import com.example.model.MyFilter;

public interface MyEntityRepository extends JpaRepository<MyEntity, Long> {

    @Query("SELECT e FROM MyEntity e WHERE e.title = :#{#filter.title}")
    Page<MyEntity> list1(@Param("filter") MyFilter filter, Pageable pageable);

}

“过滤器”：

package com.example.model;

public class MyFilter {

    private String title;

    public MyFilter(String title) {
        this.title = title;
    }

    public String getTitle() {
        return title;
    }

}

以及相关测试：

package com.example.repository;

import static org.hamcrest.CoreMatchers.is;
import static org.hamcrest.MatcherAssert.assertThat;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.domain.PageRequest;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.transaction.annotation.Transactional;

import com.example.model.MyEntity;
import com.example.model.MyFilter;

@RunWith(SpringRunner.class)
@Transactional
@SpringBootTest
public class MyEntityRepositoryTests {

    @Autowired
    private MyEntityRepository myEntityRepository;

    @Test
    public void insertAndReceiveEntityBySpEL() {
        final String titleA = "A";
        final String titleB = "B";

        final MyEntity entityA = new MyEntity(titleA);
        final MyEntity entityB = new MyEntity(titleB);
        final MyEntity entityB2 = new MyEntity(titleB);

        myEntityRepository.save(entityA);
        myEntityRepository.save(entityB);
        myEntityRepository.save(entityB2);

        final MyFilter filterA = new MyFilter(titleA);
        final MyFilter filterB = new MyFilter(titleB);

        assertThat("Expected one hit for value A!", myEntityRepository.list1(filterA, new PageRequest(0, 5)).getContent().size(), is(1));
        assertThat("Expected two hits for value B!", myEntityRepository.list1(filterB, new PageRequest(0, 5)).getContent().size(), is(2));
    }

}

也许你也可以简化你的代码，找出到底哪里出了问题。SpEL表达式不应该是真正的问题。

其他一些事情也不能成为你的错误的原因，但它似乎很奇怪：

>

titleFilter（）和idFilter（）的方法是什么？您没有在这里使用它，查询也不会使用它。

如何在运行时设置/调整MyFilter对象的成员title的值？它只是硬编码的吗？因此没有getter，JPA应该如何访问并使用它进行比较？

为什么您的存储库要扩展JpaSpecificationExecutor？

最后一件事是最令人困惑的。有没有可能你想使用规范？然后你需要一些谓词检查来实现你的“过滤器”。

Answer 2

private String title = "title title1";

过滤器的标题是私有的，我看不到这个属性的任何getter。可能是这个问题。

Answer 3

当我错过了查询花括号中的“附加”#字符时，我也有同样的问题，所以在你的情况下，你会有：

@Query("SELECT e FROM eg.domain.MyEntity e     WHERE e.title = ?#{filter.title}"

但本该如此

@Query("SELECT e FROM eg.domain.MyEntity e     WHERE e.title = ?#{#filter.title}"

注意：？#{filter.title}而不是? #{# filter.title}"

这与您粘贴的代码并不完全匹配，但可能会帮助其他人。