JAVA 抓取网页中内容处理

通过JAVA的API可以顺利的抓取网络上的大部分指定的网页内容。最简单的一种抓取方法就是：

URL url = new URL(myurl);

BufferedReader br = new BufferedReader(newInputStreamReader(url.openStream()));

String s = "";

StringBuffer sb = new StringBuffer("");

while ((s = br.readLine()) != null) {

i++;

sb.append(s+"\r\n");

}

URL url = new URL(myurl);

BufferedReader br = new BufferedReader(newInputStreamReader(url.openStream()));

String s = "";

StringBuffer sb = new StringBuffer("");

while ((s = br.readLine()) != null) {

i++;

sb.append(s+"\r\n");

}

 

这种方法抓取一般的网页应该没有问题，但当有些网页中存在一些嵌套的redirect连接时，它就会报Server redirected too many times这样的错误，这是因为此网页内部又有一些代码是转向其它网页的，循环过多导致程序出错。如果只想抓取本URL中的网页内容，而不愿意让它有其它的网页跳转，可以用以下的代码。

 

URL urlmy = new URL(myurl);

HttpURLConnection con = (HttpURLConnection) urlmy.openConnection();

con.setFollowRedirects(true);

con.setInstanceFollowRedirects(false);

con.connect();

BufferedReader br = new BufferedReader(new InputStreamReader(con.getInputStream(),"UTF-8"));

String s = "";

StringBuffer sb = new StringBuffer("");

while ((s = br.readLine()) != null) {

sb.append(s+"\r\n");

}

URL urlmy = new URL(myurl);

HttpURLConnection con = (HttpURLConnection) urlmy.openConnection();

con.setFollowRedirects(true);

con.setInstanceFollowRedirects(false);

con.connect();

BufferedReader br = new BufferedReader(new InputStreamReader(con.getInputStream(),"UTF-8"));

String s = "";

StringBuffer sb = new StringBuffer("");

while ((s = br.readLine()) != null) {

sb.append(s+"\r\n");

}

 

 

 

完整的示例代码    netpc.java ：

      package cn.com.bps.test;

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

public class netpc {

 public static void main(String[] args) {
  
  //要获取的网页地址
  String myurl = "http://localhost:8080/mydomain/index.jsp";
 
  URL urlmy = null;
  HttpURLConnection con =null;
  try {
   urlmy = new URL(myurl);
   con = (HttpURLConnection) urlmy.openConnection();
  // con.setFollowRedirects(true);
   con.setInstanceFollowRedirects(false);
   con.connect();
   
   BufferedReader br = new BufferedReader(new InputStreamReader(con.getInputStream(),"UTF-8"));

   String len = "";
   while ((len = br.readLine()) != null) {
    //输出页面上取得的字符串做处理
    System.out.println(len);
   }
   
  } catch (Exception e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
 }

}