Java实现-------网络蜘蛛

package com.insist.entity;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
* 网络蜘蛛类
* @author SNOOPY
*/
public class Spider {
/**
*
* @param srcLink  要获取网页源码的路径
* @param encoding	编码格式
* @return
*/
public static String getPageHtmlSource(String srcLink){
//List<String> list = new ArrayList<String>();
InputStream inputStream = null;
InputStreamReader inputStreamReader =null;
BufferedReader bufferedReader = null;
StringBuilder strBuilder = null;
String htmlcode = null;
try {
//1、建立与网页服务器连接
URL url = new URL(srcLink);
URLConnection urlconnection =url.openConnection();//打开链接
//urlconnection.setRequestProperty("User-Agent", "java");

String encoding = getHtmlEncoding(srcLink,url);
System.out.println("encoding====="+encoding);
//2、通过该连接，读取数据(获取输入流)
inputStream = urlconnection.getInputStream();//得到字节输入流
inputStreamReader = new InputStreamReader(inputStream,encoding);//转为字符流

bufferedReader = new BufferedReader(inputStreamReader);//构建缓冲输入流
strBuilder = new StringBuilder();//非线程安全，多线程同时访问时会有问题    但效率高  StringBuffer 线程安全

String line = null;//存储一行数据
while((line=bufferedReader.readLine())!=null){
strBuilder.append(line+"\r\n");//回车换行区别 回车： 回到同一行的起始位置，换行：换到下一行
}
htmlcode = strBuilder.toString();

} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}finally{
try {
bufferedReader.close();
inputStreamReader.close();
inputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return htmlcode;
}
public static String getHtmlEncoding(String url,URL Url){
/**
* 根据头部获取encoding
*/
String encoding = null;
try {
HttpURLConnection huc = (HttpURLConnection)Url.openConnection();
huc.connect();
Map<String,List<String>> map = huc.getHeaderFields();
Set<String> keys = map.keySet();
Iterator<String> it = keys.iterator();
String key = null;
String tmp = null;
while (it.hasNext()) {
key = it.next();
tmp = map.get(key).toString().toLowerCase();
// 获取content-type charset
if (key != null && key.equals("Content-Type")) {
int m = tmp.indexOf("charset=");//返回指定子字符串在此字符串中第一次出现处的索引。
if (m != -1) {
encoding = tmp.substring(m + 8).replace("]", "");
return encoding;
}
}
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return encoding;
}
public static void main(String[] args) {
/**
* 测试方法
* 最好用浏览器进行测试，控制台测试也可以，但是可能因为网页字符集和控制台字符集不匹配造成不能显示汉子
*/
String srcURL ="http://www.qq.com";
String html = getPageHtmlSource(srcURL);
System.out.println(html);
}
}