java中常見的遠程調用get、post請求的方法1 ：URLConnection

 

package test;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.URL;
import java.net.URLConnection;
import java.util.List;

import java.util.Map;

public class Test {
     /**
      * 向指定URL發送GET方法的請求
      *
      * @param url
      *            發送請求的URL
      * @return URL 所代表遠程資源的響應結果
      */
     public static String sendGet(String url) {
         String result = "";
         BufferedReader in = null;
         try {
             URL realUrl = new URL(url);
             // 打開和URL之間的連接
             URLConnection connection = realUrl.openConnection();
             // 設置通用的請求屬性
             connection.setRequestProperty("accept", "*/*");
             connection.setRequestProperty("connection", "Keep-Alive");
             connection.setRequestProperty("user-agent",
                     "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
             // 建立實際的連接
             connection.connect();
             // 獲取所有響應頭字段
             Map<String, List<String>> map = connection.getHeaderFields();
             // 遍歷所有的響應頭字段
             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("發送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 發送POST方法的請求
      *
      * @param url
      *            發送請求的 URL
      * @param param
      *            請求參數，請求參數應該是 name1=value1&name2=value2 的形式。
      * @return 所代表遠程資源的響應結果
      */
     public static String sendPost(String url, String param) {
         PrintWriter out = null;
         BufferedReader in = null;
         String result = "";
         try {
             URL realUrl = new URL(url);
             // 打開和URL之間的連接
             URLConnection conn = realUrl.openConnection();
             // 設置通用的請求屬性
             conn.setRequestProperty("accept", "*/*");
             conn.setRequestProperty("connection", "Keep-Alive");
             conn.setRequestProperty("user-agent",
                     "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
             // 發送POST請求必須設置如下兩行
             conn.setDoOutput(true);
             conn.setDoInput(true);
             // 獲取URLConnection對象對應的輸出流
             out = new PrintWriter(conn.getOutputStream());
            
             // 發送請求參數
             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("發送 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;
     }

}