Java tutorial
/* * Copyright 2002-2007 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 com.baidu.jprotobuf.rpc.client; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.URL; import java.net.URLConnection; import java.util.zip.GZIPInputStream; import org.springframework.context.i18n.LocaleContext; import org.springframework.context.i18n.LocaleContextHolder; import org.springframework.util.StringUtils; import com.baidu.bjf.remoting.protobuf.IDLProxyObject; import com.baidu.jprotobuf.rpc.support.IOUtils; /** * SimpleHttpRequestExecutor implementation that uses standard J2SE facilities * to execute POST requests, without support for HTTP authentication or * advanced configuration options. * * @author xiemalin * @since 1.0.0 */ public class SimpleHttpRequestExecutor extends AbstractHttpRequestExecutor { /** * Execute the given request through a standard J2SE HttpURLConnection. * <p>This method implements the basic processing workflow: * The actual work happens in this class's template methods. * * @see #openConnection * @see #prepareConnection * @see #writeRequestBody * @see #validateResponse * @see #readResponseBody * * @param invoker */ public IDLProxyObject doExecuteRequest(IDLHttpClientInvoker invoker, IDLProxyObject input, IDLProxyObject output) throws IOException { HttpURLConnection con = openConnection(invoker); int contentLength = 0; byte[] bb = null; if (input != null) { bb = input.encode(); if (bb != null) { contentLength = bb.length; } } prepareConnection(con, contentLength); if (bb != null) { ByteArrayOutputStream bos = new ByteArrayOutputStream(contentLength); bos.write(bb); writeRequestBody(con, bos); } validateResponse(con); if (output != null) { InputStream responseBody = readResponseBody(con); byte[] byteArray = IOUtils.toByteArray(responseBody); IDLProxyObject idlProxyObject = output.decode(byteArray); return idlProxyObject; } return null; } /** * Open an HttpURLConnection for the given remote invocation request. * @param config the HTTP invoker configuration that specifies the * target service * @return the HttpURLConnection for the given request * @throws IOException if thrown by I/O methods * @see java.net.URL#openConnection() */ protected HttpURLConnection openConnection(IDLHttpClientInvoker invoker) throws IOException { URLConnection con = new URL(invoker.getServiceUrl()).openConnection(); if (!(con instanceof HttpURLConnection)) { throw new IOException("Service URL [" + invoker.getServiceUrl() + "] is not an HTTP URL"); } if (invoker.getConnectTimeout() > 0) { con.setConnectTimeout(invoker.getConnectTimeout()); } if (invoker.getReadTimeout() > 0) { con.setReadTimeout(invoker.getReadTimeout()); } return (HttpURLConnection) con; } /** * Prepare the given HTTP connection. * <p>The default implementation specifies POST as method, * "application/x-java-serialized-object" as "Content-Type" header, * and the given content length as "Content-Length" header. * @param con the HTTP connection to prepare * @param contentLength the length of the content to send * @throws IOException if thrown by HttpURLConnection methods * @see java.net.HttpURLConnection#setRequestMethod * @see java.net.HttpURLConnection#setRequestProperty */ protected void prepareConnection(HttpURLConnection con, int contentLength) throws IOException { con.setDoOutput(true); con.setRequestMethod(HTTP_METHOD_POST); con.setRequestProperty(HTTP_HEADER_CONTENT_TYPE, getContentType()); con.setRequestProperty(HTTP_HEADER_CONTENT_LENGTH, Integer.toString(contentLength)); LocaleContext locale = LocaleContextHolder.getLocaleContext(); if (locale != null) { con.setRequestProperty(HTTP_HEADER_ACCEPT_LANGUAGE, StringUtils.toLanguageTag(locale.getLocale())); } if (isAcceptGzipEncoding()) { con.setRequestProperty(HTTP_HEADER_ACCEPT_ENCODING, ENCODING_GZIP); } } /** * Determine whether the given response is a GZIP response. * <p>Default implementation checks whether the HTTP "Content-Encoding" * header contains "gzip" (in any casing). * @param con the HttpURLConnection to check */ protected boolean isGzipResponse(HttpURLConnection con) { String encodingHeader = con.getHeaderField(HTTP_HEADER_CONTENT_ENCODING); return (encodingHeader != null && encodingHeader.toLowerCase().indexOf(ENCODING_GZIP) != -1); } /** * Validate the given response as contained in the HttpURLConnection 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 con the HttpURLConnection to validate * @throws IOException if validation failed * @see java.net.HttpURLConnection#getResponseCode() */ protected void validateResponse(HttpURLConnection con) throws IOException { if (con.getResponseCode() >= 300) { throw new IOException("Did not receive successful HTTP response: status code = " + con.getResponseCode() + ", status message = [" + con.getResponseMessage() + "]"); } } /** * Set the given serialized remote invocation as request body. * <p>The default implementation simply write the serialized invocation to the * HttpURLConnection's OutputStream. This can be overridden, for example, to write * a specific encoding and potentially set appropriate HTTP request headers. * @param con the HttpURLConnection to write the request body to * @param baos the ByteArrayOutputStream that contains the serialized * RemoteInvocation object * @throws IOException if thrown by I/O methods * @see java.net.HttpURLConnection#getOutputStream() * @see java.net.HttpURLConnection#setRequestProperty */ protected void writeRequestBody(HttpURLConnection con, ByteArrayOutputStream baos) throws IOException { baos.writeTo(con.getOutputStream()); } /** * Extract the response body from the given executed remote invocation * request. * <p>The default implementation simply reads the serialized invocation * from the HttpURLConnection's InputStream. If the response is recognized * as GZIP response, the InputStream will get wrapped in a GZIPInputStream. * @param con the HttpURLConnection to read the response body from * @return an InputStream for the response body * @throws IOException if thrown by I/O methods * @see #isGzipResponse * @see java.util.zip.GZIPInputStream * @see java.net.HttpURLConnection#getInputStream() * @see java.net.HttpURLConnection#getHeaderField(int) * @see java.net.HttpURLConnection#getHeaderFieldKey(int) */ protected InputStream readResponseBody(HttpURLConnection con) throws IOException { if (isGzipResponse(con)) { // GZIP response found - need to unzip. return new GZIPInputStream(con.getInputStream()); } else { // Plain response found. return con.getInputStream(); } } }