如何在 Hibernate 中获取未代理且 EAGER 获取的对象？

发布于 2024-11-03 15:04:49 字数 447 浏览 2 评论 0原文

我想加载一个对象并忘记它来自休眠！就是这样，我只是做一些事情：

MyClass myObject = MyClassDAO.getUnproxiedObject(objectID);

然后我有一个 myObj 的真实实例（而不是来自 Hibernate 代理），所有属性都使用数据库中的值设置，这样我就无法将它与手动创建的对象区分开来。

在此线程中，存在一个方法来创建未代理的对象，但它确实没有处理急于装载物体的问题，我认为这是实现我的最终目标所必需的。

对于那些想知道为什么我想要这样的对象的人，我需要使用 Gson 序列化为 Json，但我认为它对很多人来说还有很多其他用途。

原文

I want to load an objet and forget that it comes from hibernate! That's it, I just do something as:

MyClass myObject = MyClassDAO.getUnproxiedObject(objectID);

and than I have a real instance of myObj (and not from a Hibernate proxy) with all attributes set with the values from the database, so that I can't distinguish it from a manually created object.

In this thread a method is present to create an unproxied object, but it does not treats the issue of eager loding the objects, what I suppose is necessary for achieving my ultimate goals.

For those who are wondering why would I want such objects, I need to serialize then to Json with Gson, but I think it would have many other uses for many people.

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爱殇璃 2024-11-10 15:05:09

经过测试，我发现引用的帖子中给出的方法正是我想要的。

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送你一个梦 2024-11-10 15:05:09

Hibernate 在使用 GSON 渲染时不会取消代理的原因是 GSON 使用反射来序列化字段，而不是使用 Hibernate 对象的 getter。要解决此问题，您需要注册一个新的 TypeHierarchyAdapter，它将在 GSON 序列化时取消代理该对象。

这是我的方法：

GsonBuilder builder = new GsonBuilder();
builder.registerTypeHierarchyAdapter(HibernateProxy.class, new HibernateProxySerializer());
String jsonLove = gson.toJson(objToSerialize);

这是 HibernateProxySerializer：

public class HibernateProxySerializer implements JsonSerializer<HibernateProxy> {

    @Override
    public JsonElement serialize(HibernateProxy proxyObj, Type arg1, JsonSerializationContext arg2) {
        try {
            GsonBuilder gsonBuilder = new GsonBuilder();
            //below ensures deep deproxied serialization
            gsonBuilder.registerTypeHierarchyAdapter(HibernateProxy.class, new HibernateProxySerializer());
            Object deProxied = proxyObj.getHibernateLazyInitializer().getImplementation();
            return gsonBuilder.create().toJsonTree(deProxied);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}

The reason hibernate doesn't de-proxy while rendering with GSON is that GSON uses reflection to serialize the fields rather than using the getters of the Hibernate object. To workaround, you need to register a new TypeHierarchyAdapter that will de-proxy the object as GSON is serializing.

Here's my approach:

GsonBuilder builder = new GsonBuilder();
builder.registerTypeHierarchyAdapter(HibernateProxy.class, new HibernateProxySerializer());
String jsonLove = gson.toJson(objToSerialize);

Here's the HibernateProxySerializer:

public class HibernateProxySerializer implements JsonSerializer<HibernateProxy> {

    @Override
    public JsonElement serialize(HibernateProxy proxyObj, Type arg1, JsonSerializationContext arg2) {
        try {
            GsonBuilder gsonBuilder = new GsonBuilder();
            //below ensures deep deproxied serialization
            gsonBuilder.registerTypeHierarchyAdapter(HibernateProxy.class, new HibernateProxySerializer());
            Object deProxied = proxyObj.getHibernateLazyInitializer().getImplementation();
            return gsonBuilder.create().toJsonTree(deProxied);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}

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