使用Gson 2.2.2我正在尝试序列化POJO(行为)的数组列表.
我有一个适配器几乎是我在网上看到的副本：
public class BehaviorAdapter implements JsonSerializer {
private static final String CLASSNAME = "CLASSNAME";
private static final String INSTANCE = "INSTANCE";
@Override
public JsonElement serialize(Behavior src, Type typeOfSrc,
JsonSerializationContext context) {
JsonObject retValue = new JsonObject();
String className = src.getClass().getCanonicalName();
retValue.addProperty(CLASSNAME, className);
JsonElement elem = context.serialize(src);
retValue.add(INSTANCE, elem);
return retValue;
}
}
我这样注册：
GsonBuilder builder = new GsonBuilder();
builder.registerTypeHierarchyAdapter(Behavior.class, new BehaviorAdapter());
gson = builder.create();
然后,当我尝试序列化我的ArrayList时：
String json2 = gson.toJson(behaviors);
我得到一个堆栈溢出.
它似乎在线：
JsonElement elem = context.serialize(src);
它启动一个递归循环,一次又一次地通过我的序列化器.那么如何注册它以便不会发生这种情况？我需要序列化列表并维护多态性.
解决方法:
However, you should never invoke it on the src object itself since that will cause an infinite loop (Gson will call your call-back method again).
我能想到的最简单的方法是创建一个没有安装处理程序的新Gson实例,然后通过它运行实例.
作为最终运行,您可以序列化List< Behavior>代替：
public class BehaviorListAdapter implements JsonSerializer> {
private static final String CLASSNAME = "CLASSNAME";
private static final String INSTANCE = "INSTANCE";
@Override
public JsonElement serialize(List src, Type typeOfSrc,
JsonSerializationContext context) {
JsonArray array = new JsonArray();
for (Behavior behavior : src) {
JsonObject behaviorJson = new JsonObject();
String className = behavior.getClass().getCanonicalName();
behaviorJson.addProperty(CLASSNAME, className);
JsonElement elem = context.serialize(behavior);
behaviorJson.add(INSTANCE, elem);
array.add(behaviorJson);
}
return array;
}
}
GsonBuilder builder = new GsonBuilder();
// use a TypeToken to make a Type instance for a parameterized type
builder.registerTypeAdapter(
(new TypeToken>() {}).getType(),
new BehaviorListAdapter());
gson = builder.create();
标签：java,gson
来源： https://codeday.me/bug/20190713/1450552.html
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