关于 Http Get Post 请求问题

原作者：

package com.ssp.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 HttpRequest {

public static void main(String[] args) {
    //发送 GET 请求
    String s=HttpRequest.sendGet("https://www.baidu.com");
    System.out.println(s);
    
    //发送 POST 请求
    String sr=HttpRequest.sendPost("https://www.baidu.com");
    System.out.println(sr);
}








  /**
 * 向指定URL发送GET方法的请求
 * 
 * @param url
 *            发送请求的URL
 * @return URL 所代表远程资源的响应结果
 */
public static String sendGet(String url) {
    String result = "";
    BufferedReader in = null;
    try {
        String urlNameString = url;
        URL realUrl = new URL(urlNameString);
        // 打开和URL之间的连接
        URLConnection connection = realUrl.openConnection();
        // 设置通用的请求属性
        connection.setRequestProperty("accept", "*/*");
        connection.setRequestProperty("connection", "Keep-Alive");
        connection.setRequestProperty("user-agent","Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
        // 建立实际的连接
        connection.connect();
        // 获取所有响应头字段
        Map<String, List<String>> map = connection.getHeaderFields();
        // 遍历所有的响应头字段
        for (String key : map.keySet()) {
            System.out.println(key + "--->" + map.get(key));
        }
        // 定义 BufferedReader输入流来读取URL的响应
        in = new BufferedReader(new InputStreamReader(
                connection.getInputStream()));
        String line;
        while ((line = in.readLine()) != null) {
            result += line;
        }
    } catch (Exception e) {
        System.out.println("发送GET请求出现异常！" + e);
        e.printStackTrace();
    }
    // 使用finally块来关闭输入流
    finally {
        try {
            if (in != null) {
                in.close();
            }
        } catch (Exception e2) {
            e2.printStackTrace();
        }
    }
    return result;
}


/**
 * 向指定 URL 发送POST方法的请求
 * 
 * @param url
 *            发送请求的 URL
 * @return 所代表远程资源的响应结果
 */
public static String sendPost(String url) {
    PrintWriter out = null;
    BufferedReader in = null;
    String result = "";
    try {
        URL realUrl = new URL(url);
        // 打开和URL之间的连接
        URLConnection conn = realUrl.openConnection();
        // 设置通用的请求属性
        conn.setRequestProperty("accept", "*/*");
        conn.setRequestProperty("connection", "Keep-Alive");
        conn.setRequestProperty("user-agent","Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
        // 发送POST请求必须设置如下两行
        conn.setDoOutput(true);
        conn.setDoInput(true);
        // 获取URLConnection对象对应的输出流
        out = new PrintWriter(conn.getOutputStream());
        // 发送请求参数
        //out.print(param);
        // flush输出流的缓冲
        out.flush();
        // 定义BufferedReader输入流来读取URL的响应
        in = new BufferedReader(
                new InputStreamReader(conn.getInputStream()));
        String line;
        while ((line = in.readLine()) != null) {
            result += line;
        }
    } catch (Exception e) {
        System.out.println("发送 POST 请求出现异常！"+e);
        e.printStackTrace();
    }
    //使用finally块来关闭输出流、输入流
    finally{
        try{
            if(out!=null){
                out.close();
            }
            if(in!=null){
                in.close();
            }
        }
        catch(IOException ex){
            ex.printStackTrace();
        }
    }
    return result;
}  

}