package ln;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * 用於模擬HTTP請求中GET/POST方式 
 * @author landa
 *
 */
public class HttpUtils {  
    /** 
     * 傳送GET請求 
     *  
     * 
 
@param url 
     *            目的地址 
     * @param parameters 
     *            請求引數，Map型別。 
     * @return 遠端響應結果 
     */  
    public static String sendGet(String url, Map<String, String> parameters) { 
        String result="";
        BufferedReader in = null;// 讀取響應輸入流  
        StringBuffer sb = new
 
 StringBuffer();// 儲存引數  
        String params = "";// 編碼之後的引數
        try {
            // 編碼請求引數  
            if(parameters.size()==1){
                for(String name:parameters.keySet()){
                    sb.append(name).append("=").append(
                            java.net.URLEncoder.encode(parameters.get(name),  
                            
 
"UTF-8"));
                }
                params=sb.toString();
            }else{
                for (String name : parameters.keySet()) {  
                    sb.append(name).append("=").append(  
                            java.net.URLEncoder.encode(parameters.get(name),  
                                    "UTF-8")).append("&");  
                }  
                String temp_params = sb.toString();  
                params = temp_params.substring(0, temp_params.length() - 1);  
            }
            String full_url = url + "?" + params; 
            System.out.println(full_url); 
            // 建立URL物件  
            java.net.URL connURL = new java.net.URL(full_url);  
            // 開啟URL連線  
            java.net.HttpURLConnection httpConn = (java.net.HttpURLConnection) connURL  
                    .openConnection();  
            // 設定通用屬性  
            httpConn.setRequestProperty("Accept", "*/*");  
            httpConn.setRequestProperty("Connection", "Keep-Alive");  
            httpConn.setRequestProperty("User-Agent",  
                    "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1)");  
            // 建立實際的連線  
            httpConn.connect();  
            // 響應頭部獲取  
            Map<String, List<String>> headers = httpConn.getHeaderFields();  
            // 遍歷所有的響應頭欄位  
            for (String key : headers.keySet()) {  
                System.out.println(key + "\t：\t" + headers.get(key));  
            }  
            // 定義BufferedReader輸入流來讀取URL的響應,並設定編碼方式  
            in = new BufferedReader(new InputStreamReader(httpConn  
                    .getInputStream(), "UTF-8"));  
            String line;  
            // 讀取返回的內容  
            while ((line = in.readLine()) != null) {  
                result += line;  
            }  
        } catch (Exception e) {
            e.printStackTrace();
        }finally{
            try {  
                if (in != null) {  
                    in.close();  
                }  
            } catch (IOException ex) {  
                ex.printStackTrace();  
            }  
        }
        return result ;
    }  
  
    /** 
     * 傳送POST請求 
     *  
     * @param url 
     *            目的地址 
     * @param parameters 
     *            請求引數，Map型別。 
     * @return 遠端響應結果 
     */  
    public static String sendPost(String url, Map<String, String> parameters) {  
        String result = "";// 返回的結果  
        BufferedReader in = null;// 讀取響應輸入流  
        PrintWriter out = null;  
        StringBuffer sb = new StringBuffer();// 處理請求引數  
        String params = "";// 編碼之後的引數  
        try {  
            // 編碼請求引數  
            if (parameters.size() == 1) {  
                for (String name : parameters.keySet()) {  
                    sb.append(name).append("=").append(  
                            java.net.URLEncoder.encode(parameters.get(name),  
                                    "UTF-8"));  
                }  
                params = sb.toString();  
            } else {  
                for (String name : parameters.keySet()) {  
                    sb.append(name).append("=").append(  
                            java.net.URLEncoder.encode(parameters.get(name),  
                                    "UTF-8")).append("&");  
                }  
                String temp_params = sb.toString();  
                params = temp_params.substring(0, temp_params.length() - 1);  
            }  
            // 建立URL物件  
            java.net.URL connURL = new java.net.URL(url);  
            // 開啟URL連線  
            java.net.HttpURLConnection httpConn = (java.net.HttpURLConnection) connURL  
                    .openConnection();  
            // 設定通用屬性  
            httpConn.setRequestProperty("Accept", "*/*");  
            httpConn.setRequestProperty("Connection", "Keep-Alive");  
            httpConn.setRequestProperty("User-Agent",  
                    "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1)");  
            // 設定POST方式  
            httpConn.setDoInput(true);  
            httpConn.setDoOutput(true);  
            // 獲取HttpURLConnection物件對應的輸出流  
            out = new PrintWriter(httpConn.getOutputStream());  
            // 傳送請求引數  
            out.write(params);  
            // flush輸出流的緩衝  
            out.flush();  
            // 定義BufferedReader輸入流來讀取URL的響應，設定編碼方式  
            in = new BufferedReader(new InputStreamReader(httpConn  
                    .getInputStream(), "UTF-8"));  
            String line;  
            // 讀取返回的內容  
            while ((line = in.readLine()) != null) {  
                result += line;  
            }  
        } catch (Exception e) {  
            e.printStackTrace();  
        } finally {  
            try {  
                if (out != null) {  
                    out.close();  
                }  
                if (in != null) {  
                    in.close();  
                }  
            } catch (IOException ex) {  
                ex.printStackTrace();  
            }  
        }  
        return result;  
    }  
  
    /** 
     * 主函式，測試請求 
     *  
     * @param args 
     */  
    public static void main(String[] args) {  
        Map<String, String> parameters = new HashMap<String, String>();  
        parameters.put("name", "sarin");  
        String result =sendGet("http://www.baidu.com", parameters);
        System.out.println(result); 
    }  
}

轉載：https://www.cnblogs.com/vitre/p/5474166.html