Java http请求

package com.expai.utils;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.List;
import java.util.Map;
import org.apache.log4j.Logger;

public class HttpEmbed {
    private static final Logger log = Logger.getLogger(HttpEmbed.class);
    /**
     * 向指定URL发送GET方法的请求
     * 
     * @param url
     *            发送请求的URL
     * @param param
     *            请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
     * @return URL 所代表远程资源的响应结果
     */
    public static String sendGet(String url, String param) {
        String result = "";
        BufferedReader in = null;
        String urlNameString=null;
        try {
            if(param==null){
                 urlNameString = url;
            }else{
                 urlNameString = url + "?" + param;
            }
            log.info("url==========================="+urlNameString);
            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
     * @param param
     *            请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
     * @return 所代表远程资源的响应结果
     */
    public static String sendPost(String url, String param) {
        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)");
            //conn.setRequestProperty("Content-Type", "text/xml; charset=utf-8");
            // 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
            log.info("post url==========================="+url+"?"+param);
            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;
    }    
    public static void main(String[] args) {
        String str = HttpEmbed.sendGet("http://42.121.1.151:9000/hotimage", "callback=jsonp3&action=pagingImageNew&number=50&categoryId=chinayes.com&pageNum=0");
        System.out.println("============="+str);
    }
    public static String httpPost(String url, String sb ) {
        URL u = null;
        HttpURLConnection con = null;
        //构建请求参数
        /*StringBuffer sb = new StringBuffer();
        if(params!=null){
            for (Entry<String, String> e : params.entrySet()) {
            sb.append(e.getKey());
            sb.append("=");
            sb.append(e.getValue());
            sb.append("&");
            }
            sb.substring(0, sb.length() - 1);
        }*/
        System.out.println("send_url:"+url);
        System.out.println("send_data:"+sb);
        //尝试发送请求
        try {
            u = new URL(url);
            con = (HttpURLConnection) u.openConnection();
            con.setRequestMethod("POST");
            con.setDoOutput(true);
            con.setDoInput(true);
            con.setUseCaches(false);
            con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            OutputStreamWriter osw = new OutputStreamWriter(con.getOutputStream(), "UTF-8");
            osw.write(sb);
            osw.flush();
            osw.close();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (con != null) {
                con.disconnect();
            }
        }
         
        //读取返回内容
        //StringBuffer buffer = new StringBuffer();
        try {
            BufferedReader br = new BufferedReader(new InputStreamReader(con
                    .getInputStream(), "UTF-8"));
        String temp;
        /*while ((temp = br.readLine()) != null) {
        buffer.append(temp);
        buffer.append("\n");
        }*/
        } catch (Exception e) {
        e.printStackTrace();
        }
         
        return "";
        }
         
}