java 爬取网页内容。 标题、图片等

package com.fh.util;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * 说明：爬取网页
 * 作者：FH Admin
 * from：fhadmin.cn
 */
public class GetWeb {

/**
 * 获取当前网页的code
 *
 * @param httpUrl
 *            网页地址
 * @return
 * @throws IOException
 */
public static String getHtmlCode(String httpUrl) throws IOException {
String content = ""; // 定义字符串content
URL url = new URL(httpUrl); // 生成传入的URL的对象
BufferedReader reader = new BufferedReader(new InputStreamReader(
url.openStream(), "utf-8"));// 获得当前url的字节流（缓冲）
String input;
while ((input = reader.readLine()) != null) { // 当前行存在数据时
content += input; // 将读取数据赋给content
}
reader.close(); // 关闭缓冲区
return content;
}

/**
 * 把网页中的所有图片的完整路径放到list里面
 *
 * @param wwwurl
 *            要爬的网页连接
 * @throws IOException
 */
public static List<String> getImagePathList(String httpUrl)
throws IOException {

// 通过扩展名匹配网页图片的正则表达式
// String searchImgReg =
// "(?x)(src|SRC|background|BACKGROUND)=('|\")/?(([\\w-]+/)*([\\w-]+\\.(jpg|JPG|png|PNG|gif|GIF)))('|\")";
// String searchImgReg2 =
// "(?x)(src|SRC|background|BACKGROUND)=('|\")(http://([\\w-]+\\.)+[\\w-]+(:[0-9]+)*(/[\\w-]+)*(/[\\w-]+\\.(jpg|JPG|png|PNG|gif|GIF)))('|\")";
// 通过img标签匹配网页图片的正则表达式
String searchImgReg = "<(img|IMG)\\b[^>]*\\b(src|SRC|src2|SRC2)\\b\\s*=\\s*('|\")?([^'\"\n\r\f>]+(\\.jpg|\\.bmp|\\.eps|\\.gif|\\.mif|\\.miff|\\.png|\\.tif|\\.tiff|\\.svg|\\.wmf|\\.jpe|\\.jpeg|\\.dib|\\.ico|\\.tga|\\.cut|\\.pic)\\b)[^>]*>";
List<String> imgList = new ArrayList<String>(); // 存放图片的list
String content = null;
content = getHtmlCode(httpUrl);// 获得content
Pattern pattern = Pattern.compile(searchImgReg); // 讲编译的正则表达式对象赋给pattern
Matcher matcher = pattern.matcher(content); // 对字符串content执行正则表达式
while (matcher.find()) {
String quote = matcher.group(3);
String imgsrc = (quote == null || quote.trim().length() == 0) ? matcher.group(4).split("\\s+")[0] : matcher.group(4);
if (!imgsrc.startsWith("http://") && !imgsrc.startsWith("https://")) { // 检验地址是否http://
String[] httpUrlarr = httpUrl.split("/");
String wwwhost = httpUrlarr[0] + "//" + httpUrlarr[2]; //获取域名完整地址
if(!isNetFileAvailable(wwwhost + "/" + imgsrc)){
for(int i=3;i<httpUrlarr.length;i++){
wwwhost = wwwhost + "/" + httpUrlarr[i];
if(isNetFileAvailable(wwwhost + "/" + imgsrc)){
imgsrc = wwwhost + "/" + imgsrc;
break;
}
}
}else{
imgsrc = wwwhost + "/" + imgsrc;
}
}
imgList.add(imgsrc);
}
return imgList;

}

/**
 * 获取网页的标题
 *
 * @param httpUrl
 *            要爬的网页连接
 * @return
 */
public static String getTilte(String httpUrl) {

String searchTitle = "(<title>|<TITLE>)(.*?)(</title>|</TITLE>)"; // 获取网页的标题的正则表达式
Pattern pattern = Pattern.compile(searchTitle); // 获得content
try {
Matcher matcher = pattern.matcher(getHtmlCode(httpUrl));
while (matcher.find()) {
return matcher.group(2);
}
} catch (IOException e) {
e.printStackTrace();
}
return null;

}

/**
 * 检测网络资源是否存在　
 *
 * @param strUrl
 * @return
 */
public static boolean isNetFileAvailable(String strUrl) {
InputStream netFileInputStream = null;
try {
URL url = new URL(strUrl);
URLConnection urlConn = url.openConnection();
netFileInputStream = urlConn.getInputStream();
if (null != netFileInputStream) {
return true;
} else {
return false;
}
} catch (IOException e) {
return false;
} finally {
try {
if (netFileInputStream != null)
netFileInputStream.close();
} catch (IOException e) {
}
}
}
}