java调用HTTP接口

原文地址：http://www.blogjava.net/jzone/articles/277430.html

java 对HTTP网络协议的资源请求，java api上是这样说的：“每个 HttpURLConnection 实例都可用于生成单个请求，但是其他实例可以透明地共享连接到 HTTP 服务器的基础网络。”

说的再说都没用，用途简单一句话，java程序向web请求资源的。听老前辈说我这个会有问题，说是有时候不能读取完整数据。不过我是幸运的，用到现在没出现问题，先不管了。

注：在这个实例开发中，我参考了很多资料，对我的帮助都很大，实例的成功要归属这些高手们，注释主要参考下面这位仁兄。
http://www.blogjava.net/supercrsky/articles/247449.html

2009年6月29日14:07:13 PS： 对编码机制做了点改善

package com.yixun.wap;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
/**
 * 
 * @descripte use java.net.HttpURLConnection to request resource form web.
 * @author Gavin.lee
 * @date 2009-5-23 12:21:00
 * @version 1.0
 */
public class TransactionCenter {
    private URL url;
    private HttpURLConnection urlconn;

    String inencoding;
    String outencoding;
    
    public TransactionCenter(String inencoding, String outencoding) {
        this.inencoding = inencoding;
        this.outencoding = outencoding;
    }
    
    public String connect(String params, String postUrl) {
        BufferedReader br = null;
        String response = "", brLine = "";
        try {
            //params=URLEncoder.encode(params,"GB2312"); //use URLEncoder.encode for encode the params

            url = new URL(postUrl);
            urlconn = (HttpURLConnection) url.openConnection();
            urlconn.setRequestProperty("user-agent","mozilla/4.7 [en] (win98; i)");    //set request header 
            urlconn.setRequestProperty("X-Forwarded-For", "127.0.0.1");
            urlconn.setConnectTimeout(30000);
            urlconn.setReadTimeout(30000);
            urlconn.setRequestMethod("POST");     // request method, default GET
            urlconn.setUseCaches(false);    //Post can not user cache
            urlconn.setDoOutput(true);    //set output from urlconn
            urlconn.setDoInput(true);    //set input from urlconn
            OutputStream out = urlconn.getOutputStream();
            out.write(params.getBytes(outencoding));
            out.flush();
            out.close();    // output stream close,That's means need not to post data to this outputstream

            br = new BufferedReader(new InputStreamReader(urlconn.getInputStream(), inencoding));
            while((brLine = br.readLine())!=null)
                response =(new StringBuilder(String.valueOf(response))).append(brLine).toString();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if(br != null) {
                    br.close();
                }
            } catch (IOException e) {
                System.out.println("input stream close fail");
            }
            urlconn.disconnect();
        }
        return response;
    }

    public static void main(String[] args) {
        TransactionCenter tc = new TransactionCenter("GBK", "GBK");
        String response = tc.connect("c_id=10041&cpid=5&c_type=1&lotid=1&expect=08059","http://inter.boss.com/interface/client/requestwap.php?");
        System.out.println(response);
    }
}