使用Google的Gson反序列化Bugzilla JSON时出现问题 [英] Problem deserializing Bugzilla JSON using Google's Gson

问题描述

我在JSON中遇到了问题我从Bugzilla服务器回来，因为它有时会返回text：{}，有时会返回text：blah blah blah。如果没有描述错误，Bugzilla会返回前者。我很神秘，为什么它不会回复为更合理的文本：但它确实就是这样。

I'm hitting a problem in JSON I'm getting back from a Bugzilla server because it sometimes returns "text" : {} and sometimes "text" : "blah blah blah". Bugzilla returns the former if no description was given for a bug. I'm mystified why it doesn't come back as the much more sensible "text" : "" but it does and that's it.

如果我有一个String Gson的目标对象中的文本，当它看到{}情况时它会反对，因为它表示它是一个对象而不是一个字符串：

If I have a String named text in the target object for Gson, it objects when it sees the {} case because it says that's an object and not a String:

Exception in thread "main" com.google.gson.JsonParseException: The 
JsonDeserializer StringTypeAdapter failed to deserialized json object {} given 
the type class java.lang.String

关于如何让Gson解析这个的任何建议？

Any suggestions on how I can make Gson parse this?

推荐答案

Gson需要对原始问题中的情况进行自定义反序列化。以下是一个这样的例子。

Gson requires custom deserialization for the situation in the original question. Following is one such example.

input.json

[
  {
    "text":"some text"
  },
  {
    "text":{}
  }
]

Foo.java：

import java.io.FileReader;
import java.lang.reflect.Type;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;

public class Foo
{
  public static void main(String[] args) throws Exception
  {
    GsonBuilder gsonBuilder = new GsonBuilder();
    gsonBuilder.registerTypeAdapter(String.class, new StringDeserializer());
    Gson gson = gsonBuilder.create();
    Thing[] things = gson.fromJson(new FileReader("input.json"), Thing[].class);
    System.out.println(gson.toJson(things));
  }
}

class Thing
{
  String text;
}

class StringDeserializer implements JsonDeserializer<String>
{
  @Override
  public String deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
      throws JsonParseException
  {
    if (json.isJsonPrimitive()) return json.getAsString();
    return "";
  }
}

输出：

[{"text":"some text"},{"text":""}]

使用 Thing.class 类型的自定义反序列化器当然会可能。这将有利于不为每个字符串添加额外的处理，但是您将被手动处理事情。

Using instead a custom deserializer for the Thing.class type would of course be possible. This would have the benefit of not adding additional processing for every String, but then you'd be stuck with "manual" processing all of the other attributes of Thing.

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