http请求

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.URL;
import java.net.URLConnection;
import java.util.List;
import java.util.Map;

public class Csdn {



    /**
     * 向指定URL发送GET方法的请求
     *
     * @param url
     *            发送请求的URL
     * @param param
     *            请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
     * @return URL 所代表远程资源的响应结果
     */
    public static String sendGet(String url, String param) {
        String result = "";
        BufferedReader in = null;
        String urlNameString;
        try {
            if(!param.equals("")){
                urlNameString = url + "?" + param;
            }else{
                urlNameString=url;
            }
            URL realUrl = new URL(urlNameString);
            // 打开和URL之间的连接
            URLConnection connection = realUrl.openConnection();
            // 设置通用的请求属性，浏览器请求报头，不然会被有的网站检测到恶性爬网页而被禁止访问
            connection.setRequestProperty("accept", "*/*");
            connection.setRequestProperty("connection", "Keep-Alive");
            connection.setRequestProperty("user-agent",
                    "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/43.0.2357.81 Safari/537.36");
            // 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 (String key : map.keySet()) {
                System.out.println(key + " 响应头");
            }*/
            // 定义 BufferedReader输入流来读取URL的响应
            in = new BufferedReader(new InputStreamReader(
                    connection.getInputStream()));
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            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 (Exception e2) {
                e2.printStackTrace();
            }
        }
        return result;
    }

    /**
     * 向指定 URL 发送POST方法的请求
     *
     * @param url
     *            发送请求的 URL
     * @param param
     *            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
     */
    public static String sendPost(String url, String param) {
        PrintWriter out = null;
        BufferedReader in = null;
        String result = "";
        try {
            URL realUrl = new URL(url);
            // 打开和URL之间的连接
            URLConnection conn = realUrl.openConnection();
            // 设置通用的请求属性
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent",
                    "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/43.0.2357.81 Safari/537.36");
            // 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 = new PrintWriter(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 = new BufferedReader(
                    new InputStreamReader(conn.getInputStream()));
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            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(IOException ex){
                ex.printStackTrace();
            }
        }
        return result;
    }


    public static void main(String[]args) throws InterruptedException {

        // 如果不设置，只要代理IP和代理端口正确,此项不设置也可以
        System.getProperties().setProperty("http.proxyHost", "10.22.40.32");
        System.getProperties().setProperty("http.proxyPort", "8080");
        // 判断代理是否设置成功
        // 发送 GET 请求
        int i=0;
        while(true){
            Csdn.sendGet("https://blog.youkuaiyun.com/yu849893679/article/details/81332391", "");
            Csdn.sendGet("https://blog.youkuaiyun.com/yu849893679/article/details/81501862", "");
            Csdn.sendGet("https://blog.youkuaiyun.com/yu849893679/article/details/81485304", "");
            Csdn.sendGet("https://blog.youkuaiyun.com/yu849893679/article/details/81479647", "");
            Csdn.sendGet("https://blog.youkuaiyun.com/yu849893679/article/details/81205022", "");
            Csdn.sendGet("https://blog.youkuaiyun.com/yu849893679/article/details/80301249", "");
            Csdn.sendGet("https://blog.youkuaiyun.com/yu849893679/article/details/80284600", "");
            Csdn.sendGet("https://blog.youkuaiyun.com/yu849893679/article/details/81530047", "");
            Csdn.sendGet("https://blog.youkuaiyun.com/yu849893679/article/details/81530298", "");
            Csdn.sendGet("https://blog.youkuaiyun.com/yu849893679/article/details/81531173", "");
            Csdn.sendGet("https://blog.youkuaiyun.com/yu849893679/article/details/82106798", "");
            Csdn.sendGet("https://blog.youkuaiyun.com/yu849893679/article/details/82111973", "");
            Csdn.sendGet("https://blog.youkuaiyun.com/yu849893679/article/details/82142265", "");
            Csdn.sendGet("https://blog.youkuaiyun.com/yu849893679/article/details/82378230", "");
            Csdn.sendGet("https://blog.youkuaiyun.com/yu849893679/article/details/82899209", "");
            Csdn.sendGet("https://blog.youkuaiyun.com/yu849893679/article/details/82899504", "");

            /*
             * 一般网站如果检测到某个iP短时间内过频繁访问也会拒绝，因此这里设置每30秒请求一次
             *
             * */
            Thread.sleep(30*1000);
            i++;
        }
    }
}