java 爬取网页内容。标题、图片等

绝地灬酷狼 2022-09-12 10:49 232阅读 0赞

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) {
    			}
    		}
    	}
    }