Java獲取網頁資源代碼

package com.example.dangdangweb.utils;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class Getjson {

    public static String getjson(String bookid, String platnum) {

        //測試
        String s = "http://localhost:8080/sc/getprice?book_id=";
        s += bookid + "&platNum=" + platnum;

        try {
            URL url = new URL(s);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            if (200 == conn.getResponseCode()) {//如果資源存在

                System.err.print("鏈接成功");
                InputStream is = conn.getInputStream();//得到網絡的輸入流
                InputStreamReader isr = new InputStreamReader(is, "utf-8");//編碼格式
                BufferedReader br = new BufferedReader(isr);//存入Buffer緩衝區
                String str = null;
                StringBuffer buffer = new StringBuffer("");
                while ((str = br.readLine()) != null) {
                    buffer.append(str);
                }
                br.close();
                isr.close();
                is.close();

                String res = null;
                res = buffer.toString();
                return res;
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
  return null;
    }
}