URLConnection格式与用法

private void getdialog() {
    final EditText et = new EditText(this);
    final String workid = this.workid;
    new AlertDialog.Builder(this).setTitle("请输入面积").setView(et).
            setPositiveButton("确定", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface arg0, int arg1) {
                    final String size = et.getText().toString();
                    new Thread() {
                        @Override
                        public void run() {
                            httpget(workid, size);
                        }
                    }.start();
                    //Log.i("size",size);

                }
            }).show();
}

public String httpget(String workid, String size) {

    String result = "";
    BufferedReader in = null;
    StringBuilder buf = new StringBuilder("http://www.agribiotech.cn/record/record/sizerecord");
    buf.append("?");
    buf.append("workid=" + workid + "&");
    buf.append("size=" + size);


    try {
        URL url = null;
        url = new URL(buf.toString());
        URLConnection conn = url.openConnection();
        conn.setRequestProperty("Content-Type", "application/json; charset=UTF-8");
        conn.setRequestProperty("Accept", "application/json");
        conn.connect();
        Map<String, List<String>> map = conn.getHeaderFields();
        for (String key : map.keySet()) {
            System.out.println(key + "--->" + map.get(key));
        }
        in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        String line;
        while ((line = in.readLine()) != null) {
            result += "\n" + line;
        }

    } catch (IOException e) {
        Log.i("warn", e.toString());
        e.printStackTrace();
    } finally {
        try {
            if (in != null) {
                in.close();
            }
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
    return result;

}