URL url1 = new URL(yourcgistring);
        URLConnection conn1 = url1.openConnection();        conn1.setDoOutput(true);
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(conn1.getOutputStream()));
        bw.write("city=shanghai");
        bw.flush();        //URLConnection conn2 = url3.openConnection();        BufferedReader br = new BufferedReader(new InputStreamReader(conn1.getInputStream()));
        String out;
        while((out=br.readLine()) != null){
            System.out.println(out);
        }