如何在日食链接中使用表达式 (SpEL) @Query注释

Question

如何在 Spring 数据 JPA 存储库方法@Query JPA 查询中添加条件 where 子句？

例如

@Query("select student from Student student #{:rollNumber == '123' ? 'where student.rollNumber > 123' : ''} ")
List<Student> findStudents(@Param("rollNumber") int rollNumber)

我收到以下异常：-

Caused by: Exception [EclipseLink-0] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd): org.eclipse.persistence.exceptions.JPQLException
Exception Description: Syntax error parsing [select student from Student student #{:rollNumber == '123' ? 'where student.rollNumber > 123' : ''} ]. 
[62, 63] The FROM clause has 'Student student' and '#{:rollNumber =' that are not separated by a comma.
[104, 105] The identification variable '=' cannot be a reserved word.
[105, 172] The query contains a malformed ending.
    at org.eclipse.persistence.internal.jpa.jpql.HermesParser.buildException(HermesParser.java:155)
    at org.eclipse.persistence.internal.jpa.jpql.HermesParser.validate(HermesParser.java:334)
    at org.eclipse.persistence.internal.jpa.jpql.HermesParser.populateQueryImp(HermesParser.java:278)
    at org.eclipse.persistence.internal.jpa.jpql.HermesParser.buildQuery(HermesParser.java:163)
    at org.eclipse.persistence.internal.jpa.EJBQueryImpl.buildEJBQLDatabaseQuery(EJBQueryImpl.java:142)
    at org.eclipse.persistence.internal.jpa.EJBQueryImpl.buildEJBQLDatabaseQuery(EJBQueryImpl.java:116)
    at org.eclipse.persistence.internal.jpa.EJBQueryImpl.<init>(EJBQueryImpl.java:102)
    at org.eclipse.persistence.internal.jpa.EJBQueryImpl.<init>(EJBQueryImpl.java:86)
    at org.eclipse.persistence.internal.jpa.EntityManagerImpl.createQuery(EntityManagerImpl.java:1603)
    ... 74 more

Answer 1

我不确定 spring 数据当前是否将查询参数注入 SpeL 解析器。你可以尝试这样的事情：

@Query("select student from Student student where :rollNumber==123 or student.rollNumber > 123 ")
List<Student> findStudents(@Param("rollNumber") int rollNumber)