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本文主要研究一下HttpComponentsHttpInvokerRequestExecutor
HttpComponentsHttpInvokerRequestExecutor
org/springframework/remoting/httpinvoker/HttpComponentsHttpInvokerRequestExecutor.java
代码语言：javascript复制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;
@Nullable
private RequestConfig requestConfig;
/**
* Create a new instance of the HttpComponentsHttpInvokerRequestExecutor with a default
* {@link HttpClient} that uses a default {@code org.apache.http.impl.conn.PoolingClientConnectionManager}.
*/
public HttpComponentsHttpInvokerRequestExecutor() {
this(createDefaultHttpClient(), RequestConfig.custom()
.setSocketTimeout(DEFAULT_READ_TIMEOUT_MILLISECONDS).build());
}
private static HttpClient createDefaultHttpClient() {
Registry<ConnectionSocketFactory> schemeRegistry = RegistryBuilder.<ConnectionSocketFactory>create()
.register("http", PlainConnectionSocketFactory.getSocketFactory())
.register("https", SSLConnectionSocketFactory.getSocketFactory())
.build();
PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager(schemeRegistry);
connectionManager.setMaxTotal(DEFAULT_MAX_TOTAL_CONNECTIONS);
connectionManager.setDefaultMaxPerRoute(DEFAULT_MAX_CONNECTIONS_PER_ROUTE);
return HttpClientBuilder.create().setConnectionManager(connectionManager).build();
}
//......
}HttpComponentsHttpInvokerRequestExecutor继承了AbstractHttpInvokerRequestExecutor，其构造器提供了createDefaultHttpClient方法，默认注册了http及https的socketFactory，然后创建了PoolingHttpClientConnectionManager，默认maxTotal为100，defaultMaxPerRoute为5，其requestConfig默认设置了socketTimeout为60s
doExecuteRequest
代码语言：javascript复制 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();
}
}HttpComponentsHttpInvokerRequestExecutor实现了AbstractHttpInvokerRequestExecutor定义的doExecuteRequest方法，执行createHttpPost创建postMethod，然后设置requestBody，之后设置setRequestBody，接着执行executeHttpPost，验证response，读取responseBody，最后在finally里头执行postMethod.releaseConnection()
createHttpPost
代码语言：javascript复制 protected HttpPost createHttpPost(HttpInvokerClientConfiguration config) throws IOException {
HttpPost httpPost = new HttpPost(config.getServiceUrl());
RequestConfig requestConfig = createRequestConfig(config);
if (requestConfig != null) {
httpPost.setConfig(requestConfig);
}
LocaleContext localeContext = LocaleContextHolder.getLocaleContext();
if (localeContext != null) {
Locale locale = localeContext.getLocale();
if (locale != null) {
httpPost.addHeader(HTTP_HEADER_ACCEPT_LANGUAGE, locale.toLanguageTag());
}
}
if (isAcceptGzipEncoding()) {
httpPost.addHeader(HTTP_HEADER_ACCEPT_ENCODING, ENCODING_GZIP);
}
return httpPost;
}
protected RequestConfig createRequestConfig(HttpInvokerClientConfiguration config) {
HttpClient client = getHttpClient();
if (client instanceof Configurable) {
RequestConfig clientRequestConfig = ((Configurable) client).getConfig();
return mergeRequestConfig(clientRequestConfig);
}
return this.requestConfig;
}
private RequestConfig mergeRequestConfig(RequestConfig defaultRequestConfig) {
if (this.requestConfig == null) { // nothing to merge
return defaultRequestConfig;
}
RequestConfig.Builder builder = RequestConfig.copy(defaultRequestConfig);
int connectTimeout = this.requestConfig.getConnectTimeout();
if (connectTimeout >= 0) {
builder.setConnectTimeout(connectTimeout);
}
int connectionRequestTimeout = this.requestConfig.getConnectionRequestTimeout();
if (connectionRequestTimeout >= 0) {
builder.setConnectionRequestTimeout(connectionRequestTimeout);
}
int socketTimeout = this.requestConfig.getSocketTimeout();
if (socketTimeout >= 0) {
builder.setSocketTimeout(socketTimeout);
}
return builder.build();
}createHttpPost先是创建HttpPost，然后设置requestConfig，接着设置locale及gzipEncoding
setRequestBody
代码语言：javascript复制 protected void setRequestBody(
HttpInvokerClientConfiguration config, HttpPost httpPost, ByteArrayOutputStream baos)
throws IOException {
ByteArrayEntity entity = new ByteArrayEntity(baos.toByteArray());
entity.setContentType(getContentType());
httpPost.setEntity(entity);
}setRequestBody方法这里创建ByteArrayEntity，设置contentType，然后赋值给httpPost
executeHttpPost
代码语言：javascript复制 protected HttpResponse executeHttpPost(
HttpInvokerClientConfiguration config, HttpClient httpClient, HttpPost httpPost)
throws IOException {
return httpClient.execute(httpPost);
}executeHttpPost直接通过httpClient.execute方法执行post请求
getResponseBody
代码语言：javascript复制 protected InputStream getResponseBody(HttpInvokerClientConfiguration config, HttpResponse httpResponse)
throws IOException {
if (isGzipResponse(httpResponse)) {
return new GZIPInputStream(httpResponse.getEntity().getContent());
}
else {
return httpResponse.getEntity().getContent();
}
}
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));
}getResponseBody方法会先判断是否是gzip，是的话创建GZIPInputStream，否则直接取httpResponse.getEntity().getContent()
小结
HttpComponentsHttpInvokerRequestExecutor是org.springframework.remoting.httpinvoker包里头的，它继承了继承了AbstractHttpInvokerRequestExecutor，演示了httpclient的基本配置(默认maxTotal为100，defaultMaxPerRoute为5，其requestConfig默认设置了socketTimeout为60s)及其使用(创建request、设置entity、执行请求、解析response)。
