QuerySyntaxException 无效路径 + JPA + Hibernate 5.4

Question

我试图根据 CriteriaQuery 获取总行数，但出现异常

org.hibernate.hql.internal.ast.QuerySyntaxException: Invalid path: 'generatedAlias1.package.id' [select count(generatedAlias0) from com.test.Product as generatedAlias0 where ( generatedAlias1.package.id like :param0 )]

代码

CriteriaBuilder cb = session().getCriteriaBuilder();
CriteriaQuery<Product> query = cb.createQuery(Product.class);
Root<Product> entity = query.from(Product.class);
query.where(where_clause);

CriteriaQuery<Long> queryCount = cb.createQuery(Long.class);
Root<Product> entity = queryCount.from(query.getResultType());
queryCount.where(query.getRestriction()) -- this is where the problem is creating

实体

class Product{
Package package;
int quantity;

/// getter setter method

}

class Package{
String id;
String name;
String type

/// getter setter method

}

映射是使用 hbm xml 文件完成的。

你能让我知道如何解决它吗？

Answer 1

您有两个不同的查询。所以你不能对它们使用相同的谓词，因为它们有不同的根。

org.hibernate.hql.internal.ast.QuerySyntaxException：无效路径：' generatedAlias1.package.id' [从 com.test.Product 选择 count( generatedAlias0) 作为 generatedAlias0 其中（ generatedAlias1.package.id 像：param0 ）]

generatedAlias1Product是另一个查询的别名

为了使谓词可重用，您应该创建方法返回谓词

Predicate getPredicate(Root<Product> root, CriteriaBuilder builder, Parameter param) {
   // returns predicate using root, builder and param you need
   return builder.equal(root.get("fieldName"), param);
}

然后在查询中使用它

CriteriaBuilder cb = session().getCriteriaBuilder();
CriteriaQuery<Product> query = cb.createQuery(Product.class);
Root<Product> entity = query.from(Product.class);
query.where(getPredicate(entity, cb, param));

CriteriaBuilder cbCount = session().getCriteriaBuilder();
CriteriaQuery<Long> queryCount = cbCount.createQuery(Long.class);
Root<Product> entityCount = queryCount.from(Product.class);
queryCount.where(getPredicate(entityCount, cbCount, param));