Java后台使用httpclient入门HttpPost请求(form表单提交,File文件上传和传输Json数据)
一、HttpClient 简介
HttpClient 是 Apache Jakarta Common 下的子项目,用来提供高效的、最新的、功能丰富的支持 HTTP 协议的客户端编程工具包,并且它支持 HTTP 协议最新的版本和建议。Java后台使用httpclient主要目的是为了模拟客户端的请求。
2、HttpClient的请求类型
实现了所有的Http请求类型,相应的类为:HttpGet、HttpPost、HttpDelete、HttpPut
3、Http的使用流程
1)导包
<dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpclient</artifactId> <version>4.5.5</version> </dependency> <dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpmime</artifactId> <version>4.5</version> </dependency>
2)创建连接所需要的配置信息
public class HttpClientConfig { static int httpConnectTimeout = 10000;//连接超时时间(单位毫秒) static int httpSocketTimeout = 10000;//socket读写超时时间(单位毫秒) static int httpMaxPoolSize = 100; static int httpMonitorInterval = 3000; static int httpIdelTimeout = 2000; public static int getHttpIdelTimeout() { return httpIdelTimeout; } public static int getHttpSocketTimeout() { return httpSocketTimeout; } public static int getHttpMaxPoolSize() { return httpMaxPoolSize; } public static int getHttpMonitorInterval() { return httpMonitorInterval; } public static int getHttpConnectTimeout() { return httpConnectTimeout; } }
3)封装HttpClientUtils类--包括连接池的信息
public class HttpClientUtils { private final static Logger logger = Logger.getLogger(HttpClientUtils.class); private static CloseableHttpClient httpClient; private static PoolingHttpClientConnectionManager manager; // 连接池管理类 private static ScheduledExecutorService monitorExecutor; // 监控 private final static Object syncLock = new Object(); // 相当于线程锁,用于线程安全 private static final int CONNECT_TIMEOUT = HttpClientConfig.getHttpConnectTimeout();// 设置连接建立的超时时间为10s private static final int SOCKET_TIMEOUT = HttpClientConfig.getHttpSocketTimeout(); private static final int MAX_CONN = HttpClientConfig.getHttpMaxPoolSize(); // 最大连接数 private static final int Max_PRE_ROUTE = HttpClientConfig.getHttpMaxPoolSize(); private static final int MAX_ROUTE = HttpClientConfig.getHttpMaxPoolSize(); /** * 对http请求进行基本设置 * * @param httpRequestBase * http请求 */ private static void setRequestConfig(HttpRequestBase httpRequestBase) { RequestConfig requestConfig = RequestConfig.custom().setConnectionRequestTimeout(CONNECT_TIMEOUT) .setConnectTimeout(CONNECT_TIMEOUT).setSocketTimeout(SOCKET_TIMEOUT).build(); httpRequestBase.setConfig(requestConfig); } public static CloseableHttpClient getHttpClient(String url) { String hostName = url.split("/")[2]; // System.out.println(hostName); int port = 80; if (hostName.contains(":")) { String[] args = hostName.split(":"); hostName = args[0]; port = Integer.parseInt(args[1]); } if (httpClient == null) { // 多线程下多个线程同时调用getHttpClient容易导致重复创建httpClient对象的问题,所以加上了同步锁 synchronized (syncLock) { if (httpClient == null) { httpClient = createHttpClient(hostName, port); // 开启监控线程,对异常和空闲线程进行关闭 monitorExecutor = Executors.newScheduledThreadPool(1); monitorExecutor.scheduleAtFixedRate(new TimerTask() { @Override public void run() { // 关闭异常连接 manager.closeExpiredConnections(); // 关闭5s空闲的连接 manager.closeIdleConnections(HttpClientConfig.getHttpIdelTimeout(), TimeUnit.MILLISECONDS); logger.debug("close expired and idle for over 5s connection"); } }, HttpClientConfig.getHttpMonitorInterval(), HttpClientConfig.getHttpMonitorInterval(), TimeUnit.MILLISECONDS); } } } return httpClient; } /** * 根据host和port构建httpclient实例 * * @param host * 要访问的域名 * @param port * 要访问的端口 * @return */ public static CloseableHttpClient createHttpClient(String host, int port) { ConnectionSocketFactory plainSocketFactory = PlainConnectionSocketFactory.getSocketFactory(); LayeredConnectionSocketFactory sslSocketFactory = SSLConnectionSocketFactory.getSocketFactory(); Registry<ConnectionSocketFactory> registry = RegistryBuilder.<ConnectionSocketFactory> create() .register("http", plainSocketFactory).register("https", sslSocketFactory).build(); manager = new PoolingHttpClientConnectionManager(registry); // 设置连接参数 manager.setMaxTotal(MAX_CONN); // 最大连接数 manager.setDefaultMaxPerRoute(Max_PRE_ROUTE); // 路由最大连接数 HttpHost httpHost = new HttpHost(host, port); manager.setMaxPerRoute(new HttpRoute(httpHost), MAX_ROUTE); // 请求失败时,进行请求重试 HttpRequestRetryHandler handler = new HttpRequestRetryHandler() { @Override public boolean retryRequest(IOException e, int i, HttpContext httpContext) { if (i > 3) { // 重试超过3次,放弃请求 logger.error("retry has more than 3 time, give up request"); return false; } if (e instanceof NoHttpResponseException) { // 服务器没有响应,可能是服务器断开了连接,应该重试 logger.error("receive no response from server, retry"); return true; } if (e instanceof SSLHandshakeException) { // SSL握手异常 logger.error("SSL hand shake exception"); return false; } if (e instanceof InterruptedIOException) { // 超时 logger.error("InterruptedIOException"); return false; } if (e instanceof UnknownHostException) { // 服务器不可达 logger.error("server host unknown"); return false; } if (e instanceof ConnectTimeoutException) { // 连接超时 logger.error("Connection Time out"); return false; } if (e instanceof SSLException) { logger.error("SSLException"); return false; } HttpClientContext context = HttpClientContext.adapt(httpContext); HttpRequest request = context.getRequest(); if (!(request instanceof HttpEntityEnclosingRequest)) { // 如果请求不是关闭连接的请求 return true; } return false; } }; CloseableHttpClient client = HttpClients.custom().setConnectionManager(manager).setRetryHandler(handler) .build(); return client; } /** * 关闭连接池 */ public static void closeConnectionPool() { try { httpClient.close(); manager.close(); monitorExecutor.shutdown(); } catch (IOException e) { e.printStackTrace(); } } }
/** * 对http请求进行基本设置 * * @param httpRequestBase * http请求 */ private static void setRequestConfig(HttpRequestBase httpRequestBase) { RequestConfig requestConfig = RequestConfig.custom().setConnectionRequestTimeout(CONNECT_TIMEOUT) .setConnectTimeout(CONNECT_TIMEOUT).setSocketTimeout(SOCKET_TIMEOUT).build(); httpRequestBase.setConfig(requestConfig); }
4)form表单提交
public static String doPostForm(String url, Map<String, String> params) { HttpPost httpPost = new HttpPost(url); setRequestConfig(httpPost); String resultString = ""; CloseableHttpResponse response = null; try { MultipartEntityBuilder builder = MultipartEntityBuilder.create(); if (params != null) { for (String key : params.keySet()) { builder.addPart(key, new StringBody(params.get(key), ContentType.create("text/plain", Consts.UTF_8))); } } HttpEntity reqEntity = builder.build(); httpPost.setEntity(reqEntity); // 发起请求 并返回请求的响应 response = getHttpClient(url).execute(httpPost, HttpClientContext.create()); resultString = EntityUtils.toString(response.getEntity(), "utf-8"); } catch (IOException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } finally { try { if (response != null) response.close(); } catch (IOException e) { e.printStackTrace(); } } return resultString; }
5)File文件上传
public static String uploadFile(String url, String localFile, String fileParamName, Map<String, String> params) { HttpPost httpPost = new HttpPost(url); setRequestConfig(httpPost); String resultString = ""; CloseableHttpResponse response = null; try { // 把文件转换成流对象FileBody FileBody bin = new FileBody(new File(localFile)); MultipartEntityBuilder builder = MultipartEntityBuilder.create(); // 相当于<input type="file" name="file"/> builder.addPart("files", bin); // 相当于<input type="text" name="userName" value=userName> builder.addPart("filesFileName", new StringBody(fileParamName, ContentType.create("text/plain", Consts.UTF_8))); if (params != null) { for (String key : params.keySet()) { builder.addPart(key, new StringBody(params.get(key), ContentType.create("text/plain", Consts.UTF_8))); } } HttpEntity reqEntity = builder.build(); httpPost.setEntity(reqEntity); // 发起请求 并返回请求的响应 response = getHttpClient(url).execute(httpPost, HttpClientContext.create()); resultString = EntityUtils.toString(response.getEntity(), "utf-8"); } catch (IOException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } finally { try { if (response != null) response.close(); } catch (IOException e) { e.printStackTrace(); } } return resultString; }
6) 传输Json数据
public static String doPostJson(String url, String json) { HttpPost httpPost = new HttpPost(url); setRequestConfig(httpPost); String resultString = ""; CloseableHttpResponse response = null; try { // 设置ContentType(注:如果只是传普通参数的话,ContentType不一定非要用application/json) // httpPost.setHeader("Content-Type", // "application/json;charset=utf8"); httpPost.setHeader("Content-Type", "application/json"); // 创建请求内容 StringEntity entity = new StringEntity(json, ContentType.APPLICATION_JSON); httpPost.setEntity(entity); // 执行http请求 response = getHttpClient(url).execute(httpPost, HttpClientContext.create()); resultString = EntityUtils.toString(response.getEntity(), "utf-8"); } catch (Exception e) { logger.error("httpclient的get请求失败,url:" + url, e); // e.printStackTrace(); } finally { try { if (response != null) response.close(); } catch (IOException e) { logger.error("IOException的错误", e); // e.printStackTrace(); } } return resultString; }
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