java网络编程中向指定URL发送GETPOST请求示例

importjava.io.BufferedReader;
importjava.io.IOException;
importjava.io.InputStreamReader;
importjava.io.OutputStream;
importjava.io.PrintWriter;
importjava.net.HttpURLConnection;
importjava.net.URL;
importjava.net.URLConnection;
importjava.util.List;
importjava.util.Map;

publicclassHttpRequest{
    /**
     *向指定URL发送GET方法的请求
     *
     *@paramurl
     *           发送请求的URL
     *@paramparam
     *           请求参数，请求参数应该是name1=value1&name2=value2的形式。
     *@returnURL所代表远程资源的响应结果
     */
    publicstaticStringsendGet(Stringurl,Stringparam){
        Stringresult="";
        BufferedReaderin=null;
        try{
            StringurlNameString=url+"?"+param;
            URLrealUrl=newURL(urlNameString);
            //打开和URL之间的连接
            URLConnectionconnection=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;MSIE6.0;WindowsNT5.1;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(Stringkey:map.keySet()){
             *System.out.println(key+"--->"+map.get(key));}
             */
            //定义BufferedReader输入流来读取URL的响应
            in=newBufferedReader(newInputStreamReader(
                    connection.getInputStream()));
            Stringline;
            while((line=in.readLine())!=null){
                result+=line;
            }
        }catch(Exceptione){
            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(Exceptione2){
                e2.printStackTrace();
            }
        }
        returnresult;
    }

    /**
     *向指定URL发送POST方法的请求
     *
     *@paramurl
     *           发送请求的URL
     *@paramparam
     *           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
     */
    publicstaticStringsendPost(Stringurl,Stringparam){
        PrintWriterout=null;
        BufferedReaderin=null;
        Stringresult="";
        try{
            URLrealUrl=newURL(url);
            //打开和URL之间的连接
            URLConnectionconn=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;MSIE6.0;WindowsNT5.1;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=newPrintWriter(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=newBufferedReader(
                    newInputStreamReader(conn.getInputStream()));
            Stringline;
            while((line=in.readLine())!=null){
                result+=line;
            }
        }catch(Exceptione){
            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(IOExceptionex){
                ex.printStackTrace();
            }
        }
        returnresult;
    }
}