java發http請求，原地址：https://blog.csdn.net/ludonglue/article/details/78038643
阿新 • • 發佈：2018-12-18
1.使用jdk提供的URLConnection
2.使用apache提供的HttpClient（封裝了jdk）
一、使用URLConnect進行http請求
public static void main(String[] args) { //傳送 GET 請求 String s=HttpRequest.sendGet("http://baidu.com", "key=123&v=456"); System.out.println(s); //傳送 POST 請求 String sr=HttpRequest.sendPost("http://baidu.com", "key=123&v=456"); System.out.println(sr); } /** * 向指定URL傳送GET方法的請求 * * @param url 傳送請求的URL * @param param 請求引數，請求引數應該是 name1=value1&name2=value2 的形式。 * @return URL 所代表遠端資源的響應結果 */ public static String sendGet(String url, String param) { String result = ""; BufferedReader in = null; try { String urlNameString = url + "?" + param; URL realUrl = new URL(urlNameString); // 開啟和URL之間的連線 URLConnection connection = realUrl.openConnection(); // 設定通用的請求屬性 connection.setRequestProperty("accept", "*/*"); connection.setRequestProperty("connection", "Keep-Alive"); connection.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)"); // 建立實際的連線 connection.connect(); // 獲取所有響應頭欄位 Map<String, List<String>> map = connection.getHeaderFields(); // 遍歷所有的響應頭欄位 for (String key : map.keySet()) { System.out.println(key + "--->" + map.get(key)); } // 定義 BufferedReader輸入流來讀取URL的響應 in = new BufferedReader(new InputStreamReader( connection.getInputStream())); String line; while ((line = in.readLine()) != null) { result += line; } } catch (Exception e) { System.out.println("傳送GET請求出現異常！" + e); e.printStackTrace(); } // 使用finally塊來關閉輸入流 finally { try { if (in != null) { in.close(); } } catch (Exception e2) { e2.printStackTrace(); } } return result; } /** * 向指定 URL 傳送POST方法的請求 * * @param url 傳送請求的 URL * @param param 請求引數，請求引數應該是 name1=value1&name2=value2 的形式。 * @return 所代表遠端資源的響應結果 */ public static String sendPost(String url, String param) { PrintWriter out = null; BufferedReader in = null; String result = ""; try { URL realUrl = new URL(url); // 開啟和URL之間的連線 URLConnection conn = realUrl.openConnection(); // 設定通用的請求屬性 conn.setRequestProperty("accept", "*/*"); conn.setRequestProperty("connection", "Keep-Alive"); conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)"); // 傳送POST請求必須設定如下兩行 conn.setDoOutput(true); conn.setDoInput(true); // 獲取URLConnection物件對應的輸出流 out = new PrintWriter(conn.getOutputStream()); // 傳送請求引數 out.print(param); // flush輸出流的緩衝 out.flush(); // 定義BufferedReader輸入流來讀取URL的響應 in = new BufferedReader( new InputStreamReader(conn.getInputStream())); String line; while ((line = in.readLine()) != null) { result += line; } } catch (Exception e) { System.out.println("傳送 POST 請求出現異常！" + e); e.printStackTrace(); } //使用finally塊來關閉輸出流、輸入流 finally { try { if (out != null) { out.close(); } if (in != null) { in.close(); } } catch (IOException ex) { ex.printStackTrace(); } } return result; }
二、使用HttpClient進行http請求
maven依賴：
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.5.3</version>
</dependency>public static void main(String[] args) { get(); post(); } public static void get(){ /** * client和response需要關閉資源 */ //建立client,放入try()中自動釋放,不需要finally try (CloseableHttpClient client = HttpClientBuilder.create().build()){ //執行得到response try (CloseableHttpResponse response = client.execute(new HttpGet("http://www.baidu.com"))){ //獲取statusCode Integer statusCode = response.getStatusLine().getStatusCode(); HttpEntity entity = response.getEntity(); if (entity != null) { //body String bodyAsString = EntityUtils.toString(entity); //Media Type String contentMimeType = ContentType.getOrDefault(entity).getMimeType(); //head Header[] headers = response.getHeaders(HttpHeaders.CONTENT_TYPE); //輸出 System.out.println("statusCode:"+statusCode); System.out.println("contentMinmeType:"+contentMimeType); System.out.println("body:"+bodyAsString); System.out.println("head"+headers); } } } catch (IOException e) { e.printStackTrace(); } } public static void post(){ //建立client try (CloseableHttpClient client = HttpClientBuilder.create().build()){ HttpPost postRequest = new HttpPost("http://www.baidu.com"); //新增請求引數 List<NameValuePair> params = new ArrayList<>(); params.add(new BasicNameValuePair("key1", "value1")); params.add(new BasicNameValuePair("key2", "value2")); postRequest.setEntity(new UrlEncodedFormEntity(params, Consts.UTF_8)); //執行並獲取返回結果到response try (CloseableHttpResponse response = client.execute(postRequest)) { //獲取statusCode Integer statusCode = response.getStatusLine().getStatusCode(); //Media Type String contentMimeType = ContentType.getOrDefault(response.getEntity()).getMimeType(); //body String bodyAsString = EntityUtils.toString(response.getEntity()); //head Header[] headers = response.getHeaders(HttpHeaders.CONTENT_TYPE); System.out.println("statusCode:"+statusCode); System.out.println("contentMinmeType:"+contentMimeType); System.out.println("body:"+bodyAsString); System.out.println("head"+headers); } } catch (IOException e) { e.printStackTrace(); } }
程式碼：https://github.com/ludonglue/httpRequest
參考內容：
URLConnection：http://blog.csdn.net/iijse/article/details/6201101
HttpClient：http://www.baeldung.com/httpclient-guide