Java tutorial
package com.cloudhopper.httpclient.util; /* * #%L * ch-httpclient-util * %% * Copyright (C) 2012 - 2013 Cloudhopper by Twitter * %% * 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. * #L% */ import java.io.IOException; import java.util.Arrays; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.StatusLine; import org.apache.http.client.HttpClient; import org.apache.http.util.EntityUtils; /** * Utility class for processing an HttpResponse. * * @author joelauer */ public class HttpClientUtil { /** * Quitely shuts down an HttpClient instance by shutting down its connection * manager and ignoring any errors that occur. * @param http The HttpClient to shutdown */ static public void shutdownQuietly(HttpClient http) { if (http != null) { try { http.getConnectionManager().shutdown(); } catch (Exception ignore) { // do nothing } } } /** * Useful method for verifying the status code of the HttpResponse. If * the response status code does not match what we expect, this will throw * an exception. This method checks for everything including a null * response, a null statusline within the response, and then the actual * status code itself. Also, this will attempt to read the body of the * HttpResponse entity (if there was one) and include the first 100 characters * of it in the exception message. The expected, actual, and entire response * body is available within the expection itself in case further handling * is required. * @param expectedStatusCode The HttpResponse code we expect to see in the * HttpResponse. Usually, you'll want to set this to 200 for OK or HttpStatus.SC_OK. * @param response The HttpResponse to check * @throws UnexpectedHttpStatusCodeException Thrown if the actual status * code in the response does not match what we expect. */ static public void expectStatusCode(int expectedStatusCode, HttpResponse response) throws UnexpectedHttpStatusCodeException { expectStatusCodes(new int[] { expectedStatusCode }, response); /** // verify the response wasn't null if (response == null) { throw new UnexpectedHttpStatusCodeException(expectedStatusCode, "HttpResponse was null [expected statusCode=" + expectedStatusCode + "]"); } // get the status line StatusLine status = response.getStatusLine(); // verify the status line object wasn't null if (status == null) { throw new UnexpectedHttpStatusCodeException(expectedStatusCode, "HttpResponse contained a null StatusLine [expected statusCode=" + expectedStatusCode + "]"); } // verify the expected status code matches if (status.getStatusCode() != expectedStatusCode) { // prepare the error message we'll set in the exception StringBuilder message = new StringBuilder(200); String body = null; message.append("Unexpected HTTP status code: expected ["); message.append(expectedStatusCode); message.append("] actual ["); message.append(status.getStatusCode()); message.append("] reason ["); message.append(status.getReasonPhrase()); message.append("]"); // attempt to read the body of the response HttpEntity entity = response.getEntity(); if (entity != null) { try { // consume content and process it body = EntityUtils.toString(entity); // append the first 100 chars of response if (body != null) { message.append(" responseBody ["); if (body.length() > 100) { message.append(body.substring(0, 100)); } else { message.append(body); } message.append("]]"); } } catch (IOException e) { //logger.warn("IOException while trying to read content for unexpected status code", e); } finally { try { entity.consumeContent(); } catch (Exception ignore) { } } } throw new UnexpectedHttpStatusCodeException(expectedStatusCode, status.getStatusCode(), message.toString()); } */ } static public void expectStatusCodes(int[] expectedStatusCodes, HttpResponse response) throws UnexpectedHttpStatusCodeException { // verify the response wasn't null if (response == null) { throw new UnexpectedHttpStatusCodeException(expectedStatusCodes, "HttpResponse was null [expected statusCodes " + Arrays.toString(expectedStatusCodes) + "]"); } // get the status line StatusLine status = response.getStatusLine(); // verify the status line object wasn't null if (status == null) { throw new UnexpectedHttpStatusCodeException(expectedStatusCodes, "HttpResponse contained a null StatusLine [expected statusCode=" + Arrays.toString(expectedStatusCodes) + "]"); } // try to match any of the expected status codes boolean wasExpected = false; for (int expectedStatusCode : expectedStatusCodes) { if (status.getStatusCode() == expectedStatusCode) { wasExpected = true; break; } } // verify the expected status code matches if (!wasExpected) { // prepare the error message we'll set in the exception StringBuilder message = new StringBuilder(200); String body = null; message.append("Unexpected HTTP status code: expected ["); message.append(Arrays.toString(expectedStatusCodes)); message.append("] actual ["); message.append(status.getStatusCode()); message.append("] reason ["); message.append(status.getReasonPhrase()); message.append("]"); // attempt to read the body of the response HttpEntity entity = response.getEntity(); if (entity != null) { try { // consume content and process it body = EntityUtils.toString(entity); // append the first 100 chars of response if (body != null) { message.append(" responseBody ["); if (body.length() > 100) { message.append(body.substring(0, 100)); } else { message.append(body); } message.append("]]"); } } catch (IOException e) { //logger.warn("IOException while trying to read content for unexpected status code", e); } finally { try { entity.consumeContent(); } catch (Exception ignore) { } } } throw new UnexpectedHttpStatusCodeException(expectedStatusCodes, status.getStatusCode(), message.toString()); } } }