[实例]java.net.ConnectException: Connection timed out: connect

问题：

import java.io.IOException;
import java.io.OutputStream;
import java.net.Socket;
import java.net.UnknownHostException;
import java.sql.ResultSet;

import org.sql.IntoDB;

public class BaiduReferer {
 public static void main(String[] args) throws UnknownHostException,
   IOException, InterruptedException {
              for(int i=0;i<1000;i++){
                  send("");
}
}
 public static void send(String url) throws UnknownHostException,
   IOException {
  Socket socket = new Socket("www.baidu.com", 80);
  StringBuffer sb = new StringBuffer("GET /" + url + " HTTP/1.1");
  sb.append("\r\n");
  sb.append("Host: www.baidu.com");
  sb.append("\r\n");
  sb
    .append("User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.8) Gecko/20100202 Firefox/3.5.8 GTB6");
  sb.append("\r\n");
  sb
    .append("Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
  sb.append("\r\n");
  sb.append("Accept-Language: zh,en;q=0.8,zh-cn;q=0.5,en-us;q=0.3");
  sb.append("\r\n");
  sb.append("Accept-Encoding: gzip,deflate");
  sb.append("\r\n");
  sb.append("Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7");
  sb.append("\r\n");
  sb.append("Keep-Alive: 300");
  sb.append("\r\n");
  sb.append("\r\n");

  OutputStream socketOut = socket.getOutputStream();
  socketOut.write(sb.toString().getBytes());
  socket.shutdownOutput();   //半闭输出流

if(socket!=null){
  socket.close();
}
 }
}

在连接400-500次的时候，就报java.net.ConnectException: Connection timed out: connect异常

for(int i=0;i<1000;i++){
                  send("");
                  Thread(5000);
}

//结果是一样的

回答：

百度有防同一IP地址访问压力过大的屏蔽.

要是这样的话.
建议你把你的Socket 设置为多线程模式.进行sleep休眠.比如说访问一次停止2秒.或者更长.这样就不会有这个问题了.