【问题标题】:JSON parser works on emulator but not on phoneJSON解析器适用于模拟器但不适用于手机
【发布时间】:2013-03-28 12:21:01
【问题描述】:

我有一个要求,我的代码使用 json 解析器从 url 中提取信息。它在具有 android 2.2 部署的模拟器上运行良好。但是当我将它们部署在手机上(galaxy y duos(2.3) 或 S2(4.0))时,它不会给出空指针异常。您能否说明为什么会出现这种行为以及要在移动设备上进行哪些更改。

【问题讨论】:

  • 手机上网
  • 您的应用程序崩溃了吗?如果是,请与我们分享错误和代码。
  • 你可能想显示导致 NPE 的代码,否则我们只能得出结论:'你犯了一个错误......'

标签: android json


【解决方案1】:

我遇到同样的问题,试试下面的代码

您应该从 org.apache.http.conn.ssl.SSLSocketFactory 创建一个自定义类

MySSLSocketFactory.java

public class MySSLSocketFactory extends SSLSocketFactory {
    SSLContext sslContext = SSLContext.getInstance("TLS");

    public MySSLSocketFactory(KeyStore truststore) throws NoSuchAlgorithmException, KeyManagementException, KeyStoreException, UnrecoverableKeyException {
        super(truststore);

        TrustManager tm = new X509TrustManager() {
            public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
            }

            public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {
            }

            public X509Certificate[] getAcceptedIssuers() {
                return null;
            }
        };

        sslContext.init(null, new TrustManager[] { tm }, null);
    }

    @Override
    public Socket createSocket(Socket socket, String host, int port, boolean autoClose) throws IOException, UnknownHostException {
        return sslContext.getSocketFactory().createSocket(socket, host, port, autoClose);
    }

    @Override
    public Socket createSocket() throws IOException {
        return sslContext.getSocketFactory().createSocket();
    }
}

调用HttpClient

HttpClient httpclient = getNewHttpClient();

StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
                .permitAll().build();
        StrictMode.setThreadPolicy(policy);


public HttpClient getNewHttpClient() {
        try {
            KeyStore trustStore = KeyStore.getInstance(KeyStore
                    .getDefaultType());
            trustStore.load(null, null);

            SSLSocketFactory sf = new MySSLSocketFactory(trustStore);
            sf.setHostnameVerifier(SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);

            HttpParams params = new BasicHttpParams();
            HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);
            HttpProtocolParams.setContentCharset(params, HTTP.UTF_8);

            SchemeRegistry registry = new SchemeRegistry();
            registry.register(new Scheme("http", PlainSocketFactory
                    .getSocketFactory(), 80));
            registry.register(new Scheme("https", sf, 443));



            ClientConnectionManager ccm = new ThreadSafeClientConnManager(
                    params, registry);

            return new DefaultHttpClient(ccm, params);
        } catch (Exception e) {
            return new DefaultHttpClient();
        }
    }

【讨论】:

  • 您好,感谢您的回复,从这段代码中,我了解到我们正在建立一个 http 连接。但是如何获取第一个 json 对象的处理程序呢??
  • 你只需要使用我在 ans 中给出的 getNewHttpClient() 和类文件,而不是 DefaultHttpClient()
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