Gson实现自定义解析json格式

客户端跟服务器交互的时候我们使用json实现 但是 在交互的时候除了传送json对象数据意外 我们还需要传输标志位等

比如我们现在的交互方式格式

对象

{
    "data": {
        "age": 29,
        "name": "wangzhiqiang",
        "sex": 1
    },
    "message": "ok",
    "status": 200
}

列表

{
    "data": [
        {
            "age": 29,
            "name": "wangzhiqiang",
            "sex": 1
        },
        {
            "age": 29,
            "name": "wangzhiqiang",
            "sex": 1
        }
    ],
    "message": "ok",
    "status": 200
}

出错

{
    "message": "用户密码不正确！",
    "status": 355
}

gson官方文档：

http://google-gson.googlecode.com/svn/trunk/gson/docs/javadocs/index.html

JsonParser  解析json文本的解析器，它将json文本解析成JsonElement树。

JsonElement 用来表示一个json元素的类，它可能是JsonObject,JsonArray,JsonPrimitive,JsonNull.

这样我们就可以首先解析跟服务器预定的交互格式了demo：

		try {
			String json = new String(response.data,
					HttpHeaderParser.parseCharset(response.headers));
			// #1 解析code message code=200&& message="ok"代表成功

			JsonPraser parser = new JsonParser();
			JsonObject root = parser.parse(json).getAsJsonObject();
			int code = root.get("code").getAsInt();
			String message = root.get("message").getAsString();
			if (code == HttpStatus.SC_OK) {// 操作成功
				return parseNetworkResponse(root, response);
			} else {
				return Response.error(new NetError(code, message));
			}
		} catch (UnsupportedEncodingException e) {
			return Response.error(new ParseError(e));
		} catch (com.google.gson.JsonSyntaxException e) {
			return Response.error(new ParseError(e));
		}

主要源码（请求使用volley）：

public abstract class DRequest<T> extends Request<T> {

	protected String KEY_CONTENT = "content";
	protected String KEY_DATA = "data";

	Map<String, String> mParams;

	public DRequest(String url,ErrorListener errorListener) {
		this(Method.POST, url,new HashMap<String, String>(),errorListener);
	}
	public DRequest(String url,Map<String, String> params,ErrorListener errorListener) {
		this(Method.POST, url,params,errorListener);
	}

	public DRequest(int method, String url,Map<String, String> params,ErrorListener errorListener) {
		super(method, url, errorListener);
		this.mParams = params;
	}

	@Override
	protected Response<T> parseNetworkResponse(NetworkResponse response) {
		try {
			String json = new String(response.data,
					HttpHeaderParser.parseCharset(response.headers));
			// #1 解析code message code=200&& message="ok"代表成功

			JsonParser parser = new JsonParser();
			JsonObject root = parser.parse(json).getAsJsonObject();
			int code = root.get("code").getAsInt();
			String message = root.get("message").getAsString();
			if (code == HttpStatus.SC_OK) {// 操作成功
				return parseNetworkResponse(root, response);
			} else {
				return Response.error(new NetError(code, message));
			}
		} catch (UnsupportedEncodingException e) {
			return Response.error(new ParseError(e));
		} catch (com.google.gson.JsonSyntaxException e) {
			return Response.error(new ParseError(e));
		}
	}

	@Override
	public Map<String, String> getParams() throws AuthFailureError {
		return mParams;
	}

	public void put(String key, String value) {
		mParams.put(key, value);
	}

	/**
	 * 子类实现解析
	 * 
	 * @param root
	 * @param response
	 * @return
	 */
	public abstract Response<T> parseNetworkResponse(JsonObject root,
			NetworkResponse response);

	

}

public class DJsonRequest<T> extends DRequest<DataContainer<T>> {

	private Type type;
	private RequestHandler<T> handler;

	public DJsonRequest(String url,RequestHandler<T> handler, Type type) {
		super(url, handler);
		this.type = type;
		this.handler =handler;
	}

	public DJsonRequest(int method, String url,
			Map<String, String> params, RequestHandler<T> handler, Type type) {
		super(method,url, params,handler);
		this.type = type;
		this.handler =handler;
	}

	@Override
	public Response<DataContainer<T>> parseNetworkResponse(JsonObject root,
			NetworkResponse response) {
		Log.d("MyNet","获得响应");
		// data 元素
		JsonElement dataElement = root.get(KEY_DATA);

		if (dataElement.isJsonNull()) {// 不存在数据
			return Response.error(new NetError(703, "data空!"));
		}
		JsonObject data = dataElement.getAsJsonObject();
		JsonElement contentElement = data.get(KEY_CONTENT);
		if (contentElement.isJsonNull()) {// content 里面是null
			return Response.error(new NetError(702, "content空!"));
		}
		if (contentElement.isJsonObject()) {// conatent里面是对象
			T result = new Gson().fromJson(contentElement, type);
			DataContainer<T> container = new DataContainer<T>();
			container.dataSingle = result;
			return Response.success(container,
					HttpHeaderParser.parseCacheHeaders(response));
		}
		if (contentElement.isJsonArray()) {// 数组
			List<T> list = new Gson().fromJson(contentElement, type);
			DataContainer<T> container = new DataContainer<T>();
			container.dataList = list;
			return Response.success(container,
					HttpHeaderParser.parseCacheHeaders(response));
		}

		return Response.error(new NetError(703, "data空!"));
	}

	@Override
	protected void deliverResponse(DataContainer<T> response) {
		if (handler!=null) {
			handler.onResponse(response);
		}
	}


}

注意（我的json格式中有content元素 ）

现在我们直接解析data元素了  嬷嬷哒~

来自为知笔记(Wiz)