Android-Android开发：调用JSON数据出错

Question

开发的项目在2.3 2.1的手机上可以调到JSON数据 到4.0的手机上无法获取数据

开发的版本是2.1的 最小2.1的

/**
 * @author frankiewei. Json封装的工具类.
 */
public class JSONUtil {
    
    private static String RootUrl = "http://app.wishgift.cn/";
    private static String AppUrl = RootUrl
            + "?format=json";
    private static final String TAG = "JSONUtil";

    /**
     * 获取json内容
     * 
     * @param url
     * @return JSONArray
     * @throws JSONException
     * @throws ConnectionException
     */
    public static JSONObject getJSON(String url) throws JSONException,
            Exception {
            url = AppUrl+url;
        return new JSONObject(getRequest(url));
    }

    /**
     * 向api发送get请求，返回从后台取得的信息。
     * 
     * @param url
     * @return String
     */
    protected static String getRequest(String url) throws Exception {
        return getRequest(url, new DefaultHttpClient(new BasicHttpParams()));
    }

    /**
     * 向api发送get请求，返回从后台取得的信息。
     * 
     * @param url
     * @param client
     * @return String
     */
    protected static String getRequest(String url, DefaultHttpClient client)
            throws Exception {
        String result = null;
        int statusCode = 0;
        HttpGet getMethod = new HttpGet(url);
        Log.d(TAG, "do the getRequest,url=" + url + "");
        try {
            // getMethod.setHeader("User-Agent", USER_AGENT);

            HttpResponse httpResponse = client.execute(getMethod);
            // statusCode == 200 正常
            statusCode = httpResponse.getStatusLine().getStatusCode();
            Log.d(TAG, "statuscode = " + statusCode);
            // 处理返回的httpResponse信息
            result = retrieveInputStream(httpResponse.getEntity());
            Log.d(TAG, "json = " + result);
        } catch (Exception e) {
            Log.e(TAG, e.getMessage());
            throw new Exception(e);
        } finally {
            getMethod.abort();
        }
        return result;
    }

    /**
     * 处理httpResponse信息,返回String
     * 
     * @param httpEntity
     * @return String
     */
    protected static String retrieveInputStream(HttpEntity httpEntity) {

        int length = (int) httpEntity.getContentLength();
        // the number of bytes of the content, or a negative number if unknown.
        // If the content length is known but exceeds Long.MAX_VALUE, a negative
        // number is returned.
        // length==-1，下面这句报错，println needs a message
        if (length < 0)
            length = 10000;
        StringBuffer stringBuffer = new StringBuffer(length);
        try {
            InputStreamReader inputStreamReader = new InputStreamReader(
                    httpEntity.getContent(), HTTP.UTF_8);
            char buffer[] = new char[length];
            int count;
            while ((count = inputStreamReader.read(buffer, 0, length - 1)) > 0) {
                stringBuffer.append(buffer, 0, count);
            }
        } catch (UnsupportedEncodingException e) {
            Log.e(TAG, e.getMessage());
        } catch (IllegalStateException e) {
            Log.e(TAG, e.getMessage());
        } catch (IOException e) {
            Log.e(TAG, e.getMessage());
        }
        return stringBuffer.toString();
    }
}

Answer 1

我们好像也遇到过这个问题。

4.0下的json库和以前的json库不同，应该是遇到了特殊字符导致解析出现问题。

可以先打印出来，再逐个排除下。

另外回收数据的代码建议用

HttpEntity entity = httpResponse.getEntity();
response = EntityUtils.toString(entity, HTTP.UTF_8);

不需要自己处理InputStream了。