带有oracle12c JSON_VALUE函数的JPA Criteria API [英] JPA Criteria api with oracle12c JSON_VALUE function

问题描述

我正在尝试使用JSON_VALUE function()创建Criteria API查询是Oracle12c:

I'm trying to crete Criteria API query with JSON_VALUE function() is Oracle12c:

select * from orderswhere (JSON_VALUE(duty, '$.department') in ( ? , ? , ? ,? , ? , ? , ?));

型号:

@Entity
@Table(name = "orders")
@EntityListeners(AuditingEntityListener.class)
public class Trade implements Serializable {
     @Convert(converter = JpaConverterJson.class)
     private Map<String, Object> duty;
     .....
}

private Specification<InvoicePurchase> reportFormToSpec(Map<String, Object> 
    params) {
        return (root, query, cb) -> {
             List<Predicate> predicates = new ArrayList<>();
       if (!StringUtils.isEmpty(params.get("department"))) {
            Predicate predicate = cb.like(cb.function("json_value", String.class,
                    root.get("duty"),
                    cb.literal("$.department"))
                    , params.get("department"));
            predicates.add(predicate);
        }
            return query.where(predicates.toArray(new Predicate[predicates.size()])).getRestriction();
        };

    }

但是出现异常:o.h.engine.jdbc.spi.SqlExceptionHelper:ORA-40454:路径表达式不是文字

But getting exception: o.h.engine.jdbc.spi.SqlExceptionHelper: ORA-40454:path expression not a literal

我正在网上搜索很长时间.但是没用.请提供帮助或尝试提供一些想法，以实现这一目标.

I am searching for a long time on net. But no use. Please help or try to give some ideas how to achieve this.

错误代码:

   2017-11-23 12:26:55.271  WARN 11972 --- [nio-8080-exec-1] o.h.engine.jdbc.spi.SqlExceptionHelper   : SQL Error: 40454, SQLState: 99999
   2017-11-23 12:26:55.271 ERROR 11972 --- [nio-8080-exec-1] o.h.engine.jdbc.spi.SqlExceptionHelper   : ORA-40454: path expression not a literal

推荐答案

不起作用的原因是，Hibernate在后台会生成这样的SQL:

The reason this is not working, is that in the background, Hibernate will generate such an SQL:

SELECT * FROM T WHERE JSON_VALUE(?, ?)=?

..，这不适用于Oracle.

.. and this does not work with Oracle.

解决方案是内联这些值.首先是一个小助手类:

The solution is, to inline these values. First a small helper class:

public class HibernateInlineExpression extends LiteralExpression<String> {

  public HibernateInlineExpression(CriteriaBuilder criteriaBuilder, String literal) {
      super((CriteriaBuilderImpl) criteriaBuilder, literal);
  }

  @Override
  public String render(RenderingContext renderingContext) {
      return getLiteral();
  }
}

使用上述方法，您现在可以在谓词中执行JSON表达式:

Using the above, you can now do JSON expressions in predicates:

cb.equal(cb.function("JSON_VALUE", String.class,
                new HibernateInlineExpression(cb, "JSON_COLUMN"),
                new HibernateInlineExpression(cb, "'$.my.json.property'")),
  new LiteralExpression<>((CriteriaBuilderImpl) cb, String.class, "somevalue"));

当然，以上是特定于Hibernate的实现，EclipseLink等的用户必须提出类似的建议.请参阅我的有关使用JSON函数的博客文章来自JPA/Hibernate的Oracle 的一些其他技巧.

Of course the above is a Hibernate-specific implementation, users of EclipseLink, etc. have to come up with something similar. See my blog post about using JSON functions of Oracle from JPA/Hibernate for some other tricks.

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