Java tutorial
/* Android Asynchronous Http Client Copyright (c) 2011 James Smith <james@loopj.com> http://loopj.com Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. */ package cn.edu.zzu.wemall.http; import android.os.Handler; import android.os.Looper; import android.os.Message; import android.util.Log; import org.apache.http.Header; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.StatusLine; import org.apache.http.client.HttpResponseException; import org.apache.http.util.ByteArrayBuffer; import java.io.IOException; import java.io.InputStream; import java.io.UnsupportedEncodingException; import java.lang.ref.WeakReference; /** * Used to intercept and handle the responses from requests made using * {@link AsyncHttpClient}. The {@link #onSuccess(int, org.apache.http.Header[], byte[])} method is * designed to be anonymously overridden with your own response handling code. * <p> </p> * Additionally, you can override the {@link #onFailure(int, org.apache.http.Header[], byte[], Throwable)}, * {@link #onStart()}, {@link #onFinish()}, {@link #onRetry()} and {@link #onProgress(int, int)} methods as required. * <p> </p> * For example: * <p> </p> * <pre> * AsyncHttpClient client = new AsyncHttpClient(); * client.get("http://www.google.com", new AsyncHttpResponseHandler() { * @Override * public void onStart() { * // Initiated the request * } * * @Override * public void onSuccess(int statusCode, Header[] headers, byte[] responseBody) { * // Successfully got a response * } * * @Override * public void onFailure(int statusCode, Header[] headers, byte[] responseBody, Throwable error) { * // Response failed :( * } * * @Override * public void onRetry() { * // Request was retried * } * * @Override * public void onProgress(int bytesWritten, int totalSize) { * // Progress notification * } * * @Override * public void onFinish() { * // Completed the request (either success or failure) * } * }); * </pre> */ public class AsyncHttpResponseHandler { private static final String LOG_TAG = "AsyncHttpResponseHandler"; protected static final int SUCCESS_MESSAGE = 0; protected static final int FAILURE_MESSAGE = 1; protected static final int START_MESSAGE = 2; protected static final int FINISH_MESSAGE = 3; protected static final int PROGRESS_MESSAGE = 4; protected static final int RETRY_MESSAGE = 5; protected static final int BUFFER_SIZE = 4096; private Handler handler; public static final String DEFAULT_CHARSET = "UTF-8"; private String responseCharset = DEFAULT_CHARSET; private Boolean useSynchronousMode = false; // avoid leaks by using a non-anonymous handler class // with a weak reference static class ResponderHandler extends Handler { private final WeakReference<AsyncHttpResponseHandler> mResponder; ResponderHandler(AsyncHttpResponseHandler service) { mResponder = new WeakReference<AsyncHttpResponseHandler>(service); } @Override public void handleMessage(Message msg) { AsyncHttpResponseHandler service = mResponder.get(); if (service != null) { service.handleMessage(msg); } } } public boolean getUseSynchronousMode() { return (useSynchronousMode); } /** * Set the response handler to use synchronous mode or not * * @param value true indicates that synchronous mode should be used */ public void setUseSynchronousMode(Boolean value) { useSynchronousMode = value; } /** * Sets the charset for the response string. If not set, the default is UTF-8. * * @param charset to be used for the response string. * @see <a href="http://docs.oracle.com/javase/7/docs/api/java/nio/charset/Charset.html">Charset</a> */ public void setCharset(final String charset) { this.responseCharset = charset; } public String getCharset() { return this.responseCharset; } /** * Creates a new AsyncHttpResponseHandler */ public AsyncHttpResponseHandler() { // Set up a handler to post events back to the correct thread if possible if (Looper.myLooper() != null) { handler = new ResponderHandler(this); } } // // Callbacks to be overridden, typically anonymously // /** * Fired when the request progress, override to handle in your own code * * @param bytesWritten offset from start of file * @param totalSize total size of file */ public void onProgress(int bytesWritten, int totalSize) { } /** * Fired when the request is started, override to handle in your own code */ public void onStart() { } /** * Fired in all cases when the request is finished, after both success and failure, override to handle in your own code */ public void onFinish() { } /** * Fired when a request returns successfully, override to handle in your own code * * @param content the body of the HTTP response from the server * @deprecated use {@link #onSuccess(int, Header[], byte[])} */ @Deprecated public void onSuccess(String content) { } /** * Fired when a request returns successfully, override to handle in your own code * * @param statusCode the status code of the response * @param headers the headers of the HTTP response * @param content the body of the HTTP response from the server * @deprecated use {@link #onSuccess(int, Header[], byte[])} */ @Deprecated public void onSuccess(int statusCode, Header[] headers, String content) { onSuccess(statusCode, content); } /** * Fired when a request returns successfully, override to handle in your own code * * @param statusCode the status code of the response * @param content the body of the HTTP response from the server * @deprecated use {@link #onSuccess(int, Header[], byte[])} */ @Deprecated public void onSuccess(int statusCode, String content) { onSuccess(content); } /** * Fired when a request returns successfully, override to handle in your own code * * @param statusCode the status code of the response * @param headers return headers, if any * @param responseBody the body of the HTTP response from the server */ public void onSuccess(int statusCode, Header[] headers, byte[] responseBody) { try { String response = new String(responseBody, getCharset()); onSuccess(statusCode, headers, response); } catch (UnsupportedEncodingException e) { Log.e(LOG_TAG, e.toString()); onFailure(statusCode, headers, e, null); } } /** * Fired when a request fails to complete, override to handle in your own code * * @param error the underlying cause of the failure * @deprecated use {@link #onFailure(Throwable, String)} */ @Deprecated public void onFailure(Throwable error) { } /** * Fired when a request fails to complete, override to handle in your own code * * @param error the underlying cause of the failure * @param content the response body, if any * @deprecated use {@link #onFailure(int, Header[], byte[], Throwable)} */ @Deprecated public void onFailure(Throwable error, String content) { // By default, call the deprecated onFailure(Throwable) for compatibility onFailure(error); } /** * Fired when a request fails to complete, override to handle in your own code * * @param statusCode return HTTP status code * @param error the underlying cause of the failure * @param content the response body, if any * @deprecated use {@link #onFailure(int, Header[], byte[], Throwable)} */ @Deprecated public void onFailure(int statusCode, Throwable error, String content) { // By default, call the chain method onFailure(Throwable,String) onFailure(error, content); } /** * Fired when a request fails to complete, override to handle in your own code * * @param statusCode return HTTP status code * @param headers return headers, if any * @param error the underlying cause of the failure * @param content the response body, if any * @deprecated use {@link #onFailure(int, Header[], byte[], Throwable)} */ @Deprecated public void onFailure(int statusCode, Header[] headers, Throwable error, String content) { // By default, call the chain method onFailure(int,Throwable,String) onFailure(statusCode, error, content); } /** * Fired when a request fails to complete, override to handle in your own code * * @param statusCode return HTTP status code * @param headers return headers, if any * @param responseBody the response body, if any * @param error the underlying cause of the failure */ public void onFailure(int statusCode, Header[] headers, byte[] responseBody, Throwable error) { String response; try { response = new String(responseBody, getCharset()); onFailure(statusCode, headers, error, response); } catch (UnsupportedEncodingException e) { Log.e(LOG_TAG, e.toString()); onFailure(statusCode, headers, e, null); } } /** * Fired when a retry occurs, override to handle in your own code */ public void onRetry() { } // // Pre-processing of messages (executes in background threadpool thread) // protected void sendProgressMessage(int bytesWritten, int totalSize) { sendMessage(obtainMessage(PROGRESS_MESSAGE, new Object[] { bytesWritten, totalSize })); } protected void sendSuccessMessage(int statusCode, Header[] headers, byte[] responseBody) { sendMessage(obtainMessage(SUCCESS_MESSAGE, new Object[] { statusCode, headers, responseBody })); } protected void sendFailureMessage(int statusCode, Header[] headers, byte[] responseBody, Throwable error) { sendMessage(obtainMessage(FAILURE_MESSAGE, new Object[] { statusCode, headers, responseBody, error })); } protected void sendStartMessage() { sendMessage(obtainMessage(START_MESSAGE, null)); } protected void sendFinishMessage() { sendMessage(obtainMessage(FINISH_MESSAGE, null)); } protected void sendRetryMessage() { sendMessage(obtainMessage(RETRY_MESSAGE, null)); } // Methods which emulate android's Handler and Message methods protected void handleMessage(Message msg) { Object[] response; switch (msg.what) { case SUCCESS_MESSAGE: response = (Object[]) msg.obj; if (response != null && response.length >= 3) onSuccess((Integer) response[0], (Header[]) response[1], (byte[]) response[2]); else Log.e(LOG_TAG, "SUCCESS_MESSAGE didn't got enough params"); break; case FAILURE_MESSAGE: response = (Object[]) msg.obj; if (response != null && response.length >= 4) onFailure((Integer) response[0], (Header[]) response[1], (byte[]) response[2], (Throwable) response[3]); else Log.e(LOG_TAG, "FAILURE_MESSAGE didn't got enough params"); break; case START_MESSAGE: onStart(); break; case FINISH_MESSAGE: onFinish(); break; case PROGRESS_MESSAGE: response = (Object[]) msg.obj; if (response != null && response.length >= 2) onProgress((Integer) response[0], (Integer) response[1]); else Log.e(LOG_TAG, "PROGRESS_MESSAGE didn't got enough params"); break; case RETRY_MESSAGE: onRetry(); break; } } protected void sendMessage(Message msg) { if (getUseSynchronousMode() || handler == null) { handleMessage(msg); } else if (!Thread.currentThread().isInterrupted()) { // do not send messages if request has been cancelled handler.sendMessage(msg); } } protected void postRunnable(Runnable r) { if (r != null) { handler.post(r); } } protected Message obtainMessage(int responseMessage, Object response) { Message msg; if (handler != null) { msg = handler.obtainMessage(responseMessage, response); } else { msg = Message.obtain(); if (msg != null) { msg.what = responseMessage; msg.obj = response; } } return msg; } // Interface to AsyncHttpRequest void sendResponseMessage(HttpResponse response) throws IOException { // do not process if request has been cancelled if (!Thread.currentThread().isInterrupted()) { StatusLine status = response.getStatusLine(); byte[] responseBody; responseBody = getResponseData(response.getEntity()); // additional cancellation check as getResponseData() can take non-zero time to process if (!Thread.currentThread().isInterrupted()) { if (status.getStatusCode() >= 300) { sendFailureMessage(status.getStatusCode(), response.getAllHeaders(), responseBody, new HttpResponseException(status.getStatusCode(), status.getReasonPhrase())); } else { sendSuccessMessage(status.getStatusCode(), response.getAllHeaders(), responseBody); } } } } byte[] getResponseData(HttpEntity entity) throws IOException { byte[] responseBody = null; if (entity != null) { InputStream instream = entity.getContent(); if (instream != null) { long contentLength = entity.getContentLength(); if (contentLength > Integer.MAX_VALUE) { throw new IllegalArgumentException("HTTP entity too large to be buffered in memory"); } if (contentLength < 0) { contentLength = BUFFER_SIZE; } try { ByteArrayBuffer buffer = new ByteArrayBuffer((int) contentLength); try { byte[] tmp = new byte[BUFFER_SIZE]; int l, count = 0; // do not send messages if request has been cancelled while ((l = instream.read(tmp)) != -1 && !Thread.currentThread().isInterrupted()) { count += l; buffer.append(tmp, 0, l); sendProgressMessage(count, (int) contentLength); } } finally { instream.close(); } responseBody = buffer.buffer(); } catch (OutOfMemoryError e) { System.gc(); throw new IOException("File too large to fit into available memory"); } } } return responseBody; } }