Java tutorial
/* * Copyright 2002-2012 the original author or authors. * * 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 org.springframework.remoting.httpinvoker; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.util.zip.GZIPInputStream; import org.apache.http.Header; import org.apache.http.HttpResponse; import org.apache.http.NoHttpResponseException; import org.apache.http.StatusLine; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpPost; import org.apache.http.conn.scheme.PlainSocketFactory; import org.apache.http.conn.scheme.Scheme; import org.apache.http.conn.scheme.SchemeRegistry; import org.apache.http.conn.ssl.SSLSocketFactory; import org.apache.http.entity.ByteArrayEntity; import org.apache.http.impl.client.DefaultHttpClient; import org.apache.http.impl.conn.PoolingClientConnectionManager; import org.apache.http.params.CoreConnectionPNames; import org.springframework.context.i18n.LocaleContext; import org.springframework.context.i18n.LocaleContextHolder; import org.springframework.remoting.support.RemoteInvocationResult; import org.springframework.util.Assert; import org.springframework.util.StringUtils; /** * {@link org.springframework.remoting.httpinvoker.HttpInvokerRequestExecutor} implementation that uses * <a href="http://hc.apache.org/httpcomponents-client-ga/httpclient/">Apache HttpComponents HttpClient</a> * to execute POST requests. * * <p>Allows to use a pre-configured {@link org.apache.http.client.HttpClient} * instance, potentially with authentication, HTTP connection pooling, etc. * Also designed for easy subclassing, providing specific template methods. * * <p>As of Spring 3.2, this request executor requires Apache HttpComponents 4.2 or higher. * * @author Juergen Hoeller * @since 3.1 * @see org.springframework.remoting.httpinvoker.SimpleHttpInvokerRequestExecutor */ public class HttpComponentsHttpInvokerRequestExecutor extends AbstractHttpInvokerRequestExecutor { private static final int DEFAULT_MAX_TOTAL_CONNECTIONS = 100; private static final int DEFAULT_MAX_CONNECTIONS_PER_ROUTE = 5; private static final int DEFAULT_READ_TIMEOUT_MILLISECONDS = (60 * 1000); private HttpClient httpClient; /** * Create a new instance of the HttpComponentsHttpInvokerRequestExecutor with a default * {@link HttpClient} that uses a default {@link org.apache.http.impl.conn.PoolingClientConnectionManager}. */ public HttpComponentsHttpInvokerRequestExecutor() { SchemeRegistry schemeRegistry = new SchemeRegistry(); schemeRegistry.register(new Scheme("http", 80, PlainSocketFactory.getSocketFactory())); schemeRegistry.register(new Scheme("https", 443, SSLSocketFactory.getSocketFactory())); PoolingClientConnectionManager connectionManager = new PoolingClientConnectionManager(schemeRegistry); connectionManager.setMaxTotal(DEFAULT_MAX_TOTAL_CONNECTIONS); connectionManager.setDefaultMaxPerRoute(DEFAULT_MAX_CONNECTIONS_PER_ROUTE); this.httpClient = new DefaultHttpClient(connectionManager); setReadTimeout(DEFAULT_READ_TIMEOUT_MILLISECONDS); } /** * Create a new instance of the HttpComponentsClientHttpRequestFactory * with the given {@link HttpClient} instance. * @param httpClient the HttpClient instance to use for this request executor */ public HttpComponentsHttpInvokerRequestExecutor(HttpClient httpClient) { this.httpClient = httpClient; } /** * Set the {@link HttpClient} instance to use for this request executor. */ public void setHttpClient(HttpClient httpClient) { this.httpClient = httpClient; } /** * Return the {@link HttpClient} instance that this request executor uses. */ public HttpClient getHttpClient() { return this.httpClient; } /** * Set the connection timeout for the underlying HttpClient. * A timeout value of 0 specifies an infinite timeout. * @param timeout the timeout value in milliseconds */ public void setConnectTimeout(int timeout) { Assert.isTrue(timeout >= 0, "Timeout must be a non-negative value"); getHttpClient().getParams().setIntParameter(CoreConnectionPNames.CONNECTION_TIMEOUT, timeout); } /** * Set the socket read timeout for the underlying HttpClient. * A timeout value of 0 specifies an infinite timeout. * @param timeout the timeout value in milliseconds * @see #DEFAULT_READ_TIMEOUT_MILLISECONDS */ public void setReadTimeout(int timeout) { Assert.isTrue(timeout >= 0, "Timeout must be a non-negative value"); getHttpClient().getParams().setIntParameter(CoreConnectionPNames.SO_TIMEOUT, timeout); } /** * Execute the given request through the HttpClient. * <p>This method implements the basic processing workflow: * The actual work happens in this class's template methods. * @see #createHttpPost * @see #setRequestBody * @see #executeHttpPost * @see #validateResponse * @see #getResponseBody */ @Override protected RemoteInvocationResult doExecuteRequest(HttpInvokerClientConfiguration config, ByteArrayOutputStream baos) throws IOException, ClassNotFoundException { HttpPost postMethod = createHttpPost(config); setRequestBody(config, postMethod, baos); try { HttpResponse response = executeHttpPost(config, getHttpClient(), postMethod); validateResponse(config, response); InputStream responseBody = getResponseBody(config, response); return readRemoteInvocationResult(responseBody, config.getCodebaseUrl()); } finally { postMethod.releaseConnection(); } } /** * Create a HttpPost for the given configuration. * <p>The default implementation creates a standard HttpPost with * "application/x-java-serialized-object" as "Content-Type" header. * @param config the HTTP invoker configuration that specifies the * target service * @return the HttpPost instance * @throws java.io.IOException if thrown by I/O methods */ protected HttpPost createHttpPost(HttpInvokerClientConfiguration config) throws IOException { HttpPost httpPost = new HttpPost(config.getServiceUrl()); LocaleContext locale = LocaleContextHolder.getLocaleContext(); if (locale != null) { httpPost.addHeader(HTTP_HEADER_ACCEPT_LANGUAGE, StringUtils.toLanguageTag(locale.getLocale())); } if (isAcceptGzipEncoding()) { httpPost.addHeader(HTTP_HEADER_ACCEPT_ENCODING, ENCODING_GZIP); } return httpPost; } /** * Set the given serialized remote invocation as request body. * <p>The default implementation simply sets the serialized invocation as the * HttpPost's request body. This can be overridden, for example, to write a * specific encoding and to potentially set appropriate HTTP request headers. * @param config the HTTP invoker configuration that specifies the target service * @param httpPost the HttpPost to set the request body on * @param baos the ByteArrayOutputStream that contains the serialized * RemoteInvocation object * @throws java.io.IOException if thrown by I/O methods */ protected void setRequestBody(HttpInvokerClientConfiguration config, HttpPost httpPost, ByteArrayOutputStream baos) throws IOException { ByteArrayEntity entity = new ByteArrayEntity(baos.toByteArray()); entity.setContentType(getContentType()); httpPost.setEntity(entity); } /** * Execute the given HttpPost instance. * @param config the HTTP invoker configuration that specifies the target service * @param httpClient the HttpClient to execute on * @param httpPost the HttpPost to execute * @return the resulting HttpResponse * @throws java.io.IOException if thrown by I/O methods */ protected HttpResponse executeHttpPost(HttpInvokerClientConfiguration config, HttpClient httpClient, HttpPost httpPost) throws IOException { return httpClient.execute(httpPost); } /** * Validate the given response as contained in the HttpPost object, * throwing an exception if it does not correspond to a successful HTTP response. * <p>Default implementation rejects any HTTP status code beyond 2xx, to avoid * parsing the response body and trying to deserialize from a corrupted stream. * @param config the HTTP invoker configuration that specifies the target service * @param response the resulting HttpResponse to validate * @throws java.io.IOException if validation failed */ protected void validateResponse(HttpInvokerClientConfiguration config, HttpResponse response) throws IOException { StatusLine status = response.getStatusLine(); if (status.getStatusCode() >= 300) { throw new NoHttpResponseException("Did not receive successful HTTP response: status code = " + status.getStatusCode() + ", status message = [" + status.getReasonPhrase() + "]"); } } /** * Extract the response body from the given executed remote invocation request. * <p>The default implementation simply fetches the HttpPost's response body stream. * If the response is recognized as GZIP response, the InputStream will get wrapped * in a GZIPInputStream. * @param config the HTTP invoker configuration that specifies the target service * @param httpResponse the resulting HttpResponse to read the response body from * @return an InputStream for the response body * @throws java.io.IOException if thrown by I/O methods * @see #isGzipResponse * @see java.util.zip.GZIPInputStream */ protected InputStream getResponseBody(HttpInvokerClientConfiguration config, HttpResponse httpResponse) throws IOException { if (isGzipResponse(httpResponse)) { return new GZIPInputStream(httpResponse.getEntity().getContent()); } else { return httpResponse.getEntity().getContent(); } } /** * Determine whether the given response indicates a GZIP response. * <p>The default implementation checks whether the HTTP "Content-Encoding" * header contains "gzip" (in any casing). * @param httpResponse the resulting HttpResponse to check * @return whether the given response indicates a GZIP response */ protected boolean isGzipResponse(HttpResponse httpResponse) { Header encodingHeader = httpResponse.getFirstHeader(HTTP_HEADER_CONTENT_ENCODING); return (encodingHeader != null && encodingHeader.getValue() != null && encodingHeader.getValue().toLowerCase().contains(ENCODING_GZIP)); } }