package com.lrdd.utils;


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

public class HttpRequest {
  /**
   * 向指定URL發送GET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 URL 所代表遠程資源的響應結果
   */
  public static String sendGet(String url, String param) {
    String result = "";
    BufferedReader in = null;
    try {
      String urlNameString = url + "?" + param;
      URL realUrl = new URL(urlNameString);
      // 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(new OutputStreamWriter(conn.getOutputStream(),"utf-8"));
      // 發送請求參數
      out.print(param);
      // flush輸出流的緩沖
      out.flush();
      // 定義BufferedReader輸入流來讀取URL的響應
      in = new BufferedReader(
          new InputStreamReader(conn.getInputStream(),"utf-8"));
      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;
  }  
}