詳解JAVA抓取網頁的圖片,JAVA利用正則表達式抓取網站圖片

利用Java抓取網頁上的所有圖片：

用兩個正則表達式：

1、匹配html中img標籤的正則：<img.*src=(.*?)[^>]*?>

2、匹配img標籤中得src中http路徑的正則：http:/"?(.*?)(/"|>|//s+)

實現：

 package org.swinglife.main; import java.io.File; import java.io.FileOutputStream; import java.io.InputStream; 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; /*** * java抓取網絡圖片* @author swinglife * */ public class CatchImage { // 地址private static final String URL = "http://www.csdn.net"; // 編碼private static final String ECODING = "UTF-8"; // 獲取img標籤正則private static final String IMGURL_REG = "<img.*src=(.*?)[^>]*?>"; // 獲取src路徑的正則private static final String IMGSRC_REG = "http:/"?(.*?)(/"|>|//s+)"; public static void main(String[] args) throws Exception { CatchImage cm = new CatchImage(); //獲得html文本內容String HTML = cm.getHTML(URL); //獲取圖片標籤List<String> imgUrl = cm.getImageUrl(HTML); //獲取圖片src地址List<String> imgSrc = cm.getImageSrc(imgUrl); //下載圖片cm.Download(imgSrc); } /*** * 獲取HTML內容* * @param url * @return * @throws Exception */ private String getHTML(String url) throws Exception { URL uri = new URL(url); URLConnection connection = uri.openConnection(); InputStream in = connection.getInputStream(); byte[] buf = new byte[1024]; int length = 0; StringBuffer sb = new StringBuffer(); while ((length = in.read(buf, 0, buf.length)) > 0) { sb.append(new String(buf, ECODING)); } in.close(); return sb.toString(); } /*** * 獲取ImageUrl地址* * @param HTML * @return */ private List<String> getImageUrl(String HTML) { Matcher matcher = Pattern.compile(IMGURL_REG).matcher(HTML); List<String> listImgUrl = new ArrayList<String>(); while (matcher.find()) { listImgUrl.add(matcher.group()); } return listImgUrl; } /*** * 獲取ImageSrc地址* * @param listImageUrl * @return */ private List<String> getImageSrc(List<String> listImageUrl) { List<String> listImgSrc = new ArrayList<String>(); for (String image : listImageUrl) { Matcher matcher = Pattern.compile(IMGSRC_REG).matcher(image); while (matcher.find()) { listImgSrc.add(matcher.group().substring(0, matcher.group().length() - 1)); } } return listImgSrc; } /*** * 下載圖片* * @param listImgSrc */ private void Download(List<String> listImgSrc) { try { for (String url : listImgSrc) { String imageName = url.substring(url.lastIndexOf("/") + 1, url.length()); URL uri = new URL(url); InputStream in = uri.openStream(); FileOutputStream fo = new FileOutputStream(new File(imageName)); byte[] buf = new byte[1024]; int length = 0; System.out.println("開始下載:" + url); while ((length = in.read(buf, 0, buf.length)) != -1) { fo.write(buf, 0, length); } in.close(); fo.close(); System.out.println(imageName + "下載完成"); } } catch (Exception e) { System.out.println("下載失敗"); } } }

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