HQL和内部类(例如构建器) [英] HQL and inner classes (such as builders)

问题描述

考虑采用构建器模式的 Result DTO:

Consider a Result DTO employing a builder pattern:

package com.example;
public class Result {
    int someValue;

    public static class Builder {
        private final Foo foo;
        private final Bar bar;

        public Builder(Foo foo, Bar bar) {
            this.foo = foo;
        }

        public Result build() {
            Result r = new Result();
            r.someValue = /* compute value based on supplied Foo and Bar */;
            return r;
        }
    }
}

现在，我想在HQL查询中创建构建器，例如:

Now, I want to create the builder in an HQL query, such as:

select new Result.Builder(f, b) from Foo f, Bar b where ...

但是，我最终会出错

无法找到类[com.example.Result.Builder]

Unable to locate class [com.example.Result.Builder]

一种解决方案是将Builder移至单独的类，但是我喜欢Builder与其实体整齐地包装.

One solution is to move the Builder to a separate class, but I like the Builder neatly packed with its entity.

有没有一种方法可以使Hibernate识别select子句中的内部类?

推荐答案

事实证明，我最终找到了解决方案.正确的语法是带有内部类的 $ 分隔符的完全限定名称，例如:

It turns out I found the solution in the end; The proper syntax is fully qualified name with a $ separator of inner class, such as:

select new com.example.Result$Builder(f, b) from ...

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