HttpClient发送请求 实现get，post 参数，post json，post file

1.导入HttpCLient的jar包

<dependencies> <dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpclient</artifactId> <version>4.5.2</version> </dependency> <dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpcore</artifactId> <version>4.4.6</version> </dependency> </dependencies>

以下会依次列举常见的几种请求类型 : get , post param , post json , post file

2.GET

/** * get类型的 * * @param url * @throws ClientProtocolException * @throws IOException */ public static void testGet(String url) throws ClientProtocolException, IOException { // 设置超时时间，单位是秒 RequestConfig defaultRequestConfig = RequestConfig.custom().setSocketTimeout(3000).setConnectTimeout(3000) .setConnectionRequestTimeout(3000).build(); CloseableHttpClient httpclient = HttpClients.createDefault(); try { HttpGet httpget = new HttpGet(url); httpget.setConfig(defaultRequestConfig); ResponseHandler<String> responseHandler = new ResponseHandler<String>() { public String handleResponse(HttpResponse response) throws ClientProtocolException, IOException { int status = response.getStatusLine().getStatusCode(); if (status >= 200 && status < 300) { HttpEntity entity = response.getEntity(); return entity != null ? EntityUtils.toString(entity) : null; } else { throw new ClientProtocolException("Unexpected response status: " + status); } } }; String responseBody = httpclient.execute(httpget, responseHandler); System.out.println(responseBody); } finally { httpclient.close(); } }

3.POST 参数

/** * form类型的，传参数 * * @param url * @param map 参数 * @throws ClientProtocolException * @throws IOException */ public static void testPostParam(String url,Map<String,String> map) throws ClientProtocolException, IOException { // 设置超时时间 RequestConfig defaultRequestConfig = RequestConfig.custom().setSocketTimeout(3000).setConnectTimeout(3000) .setConnectionRequestTimeout(3000).build(); CloseableHttpClient httpClient = HttpClients.custom().setDefaultRequestConfig(defaultRequestConfig).build(); httpClient = HttpClients.createDefault(); HttpPost post = new HttpPost("http://httpbin.org/post"); post.setConfig(defaultRequestConfig); // 传参数 List<BasicNameValuePair> list = new ArrayList<BasicNameValuePair>(); for(Entry<String,string> entry: map.entrySet()){ list.add(new BasicNameValuePair(entry.getKey(), entry.getValue())); } HttpEntity ent = new UrlEncodedFormEntity(list, "UTF-8"); post.setEntity(ent); ResponseHandler<String> responseHandler = new ResponseHandler<String>() { public String handleResponse(HttpResponse response) throws ClientProtocolException, IOException { int status = response.getStatusLine().getStatusCode(); System.out.println(response.getEntity().toString()); if (status >= 200 && status < 300) { HttpEntity entity = response.getEntity(); return entity != null ? EntityUtils.toString(entity) : null; } else { throw new ClientProtocolException("Unexpected response status: " + status); } } }; System.out.println(httpClient.execute(post, responseHandler)); }

4.POST JSON

/** * post json * * @param url 请求地址 * @param jsonStr 请求json字符串 * @throws ClientProtocolException * @throws IOException */ public static void testPostJson(String url,String jsonStr) throws ClientProtocolException, IOException { // 设置超时时间 RequestConfig defaultRequestConfig = RequestConfig.custom().setSocketTimeout(3000).setConnectTimeout(3000) .setConnectionRequestTimeout(3000).build(); CloseableHttpClient httpClient = HttpClients.custom().setDefaultRequestConfig(defaultRequestConfig).build(); httpClient = HttpClients.createDefault(); HttpPost post = new HttpPost(url); post.setConfig(defaultRequestConfig); // 传json字符串 "{\"key\":\"value\"}" StringEntity stringEntity = new StringEntity(jsonStr); stringEntity.setContentType("text/json"); stringEntity.setContentEncoding(new BasicHeader(HTTP.CONTENT_TYPE, "application/json")); post.setEntity(stringEntity); ResponseHandler<String> responseHandler = new ResponseHandler<String>() { public String handleResponse(HttpResponse response) throws ClientProtocolException, IOException { int status = response.getStatusLine().getStatusCode(); if (status >= 200 && status < 300) { HttpEntity entity = response.getEntity(); return entity != null ? EntityUtils.toString(entity) : null; } else { throw new ClientProtocolException("Unexpected response status: " + status); } } }; System.out.println(httpClient.execute(post, responseHandler)); }

5.POST FILE

/** * 上传文件 * @param url 上传接口地址 * @param filePath * @param fileName * @throws ClientProtocolException * @throws IOException */ public static void testPostFile(String url,String filePath,string fileName) throws ClientProtocolException, IOException { RequestConfig defaultRequestConfig = RequestConfig.custom().setSocketTimeout(5000).setConnectTimeout(3000) .setConnectionRequestTimeout(3000).build(); CloseableHttpClient httpClient = HttpClients.custom().setDefaultRequestConfig(defaultRequestConfig).build(); httpClient = HttpClients.createDefault(); HttpPost post = new HttpPost(url); // 设置超时时间 post.setConfig(defaultRequestConfig); // 传文件 MultipartEntityBuilder builder = MultipartEntityBuilder.create(); builder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE); builder.addTextBody("name", "test"); builder.addBinaryBody("file", new File(filePath), ContentType.DEFAULT_BINARY, fileName); post.setEntity(builder.build()); ResponseHandler<String> responseHandler = new ResponseHandler<String>() { public String handleResponse(HttpResponse response) throws ClientProtocolException, IOException { int status = response.getStatusLine().getStatusCode(); if (status >= 200 && status < 300) { HttpEntity entity = response.getEntity(); return entity != null ? EntityUtils.toString(entity) : null; } else { throw new ClientProtocolException("Unexpected response status: " + status); } } }; System.out.println(httpClient.execute(post, responseHandler)); }