使用jdk获取网页

参考：https://www.zhihu.com/question/30626103

由于例子比较老了，现在的百度抓不到完整的页面了

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;

public class Main {
    public static void main(String[] args) {
        String url = "https://www.baidu.com/";
        String result = "";
        // 定义一个缓冲字符输入流
        BufferedReader in = null;
        try {
            // 将String转化成url对象
            URL realUrl = new URL(url);
            // 初始化一个链接到那个url
            URLConnection connection = realUrl.openConnection();
            // 开始实际的连接
            connection.connect();
            // 初始化bufferedReader输入流来读取URL的相应
            in = new BufferedReader(new InputStreamReader(
                    connection.getInputStream()));
            // 用来临时存储抓取到的每一行数据
            String line;
            while ((line = in.readLine()) != null) {
                // 遍历抓取到的每一行并存储到result里面
                result += line + "\n";
            }
        } catch (Exception e) {
            System.out.println("发送GET请求出现异常！" + e);
            e.printStackTrace();
        } finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (Exception e2) {
                // TODO: handle exception
            }

        }
        System.out.println(result);
    }
}