


Write Java with zero foundation and practice Zhihu crawler first with Baidu homepage (3)
The complete code is as follows:
import java.io.*; import java.net.*; import java.util.regex.*; public class Main { static String SendGet(String url) { // 定义一个字符串用来存储网页内容 String result = ""; // 定义一个缓冲字符输入流 BufferedReader in = null; try { // 将string转成url对象 URL realUrl = new URL(url); // 初始化一个链接到那个url的连接 URLConnection connection = realUrl.openConnection(); // 开始实际的连接 connection.connect(); // 初始化 BufferedReader输入流来读取URL的响应 in = new BufferedReader(new InputStreamReader( connection.getInputStream())); // 用来临时存储抓取到的每一行的数据 String line; while ((line = in.readLine()) != null) { // 遍历抓取到的每一行并将其存储到result里面 result += line; } } catch (Exception e) { System.out.println("发送GET请求出现异常!" + e); e.printStackTrace(); } // 使用finally来关闭输入流 finally { try { if (in != null) { in.close(); } } catch (Exception e2) { e2.printStackTrace(); } } return result; } static String RegexString(String targetStr, String patternStr) { // 定义一个样式模板,此中使用正则表达式,括号中是要抓的内容 // 相当于埋好了陷阱匹配的地方就会掉下去 Pattern pattern = Pattern.compile(patternStr); // 定义一个matcher用来做匹配 Matcher matcher = pattern.matcher(targetStr); // 如果找到了 if (matcher.find()) { // 打印出结果 return matcher.group(1); } return "Nothing"; } public static void main(String[] args) { // 定义即将访问的链接 String url = "http://www.baidu.com"; // 访问链接并获取页面内容 String result = SendGet(url); // 使用正则匹配图片的src内容 String imgSrc = RegexString(result, "src=\"(.+?)\""); // 打印结果 System.out.println(imgSrc); } }
In this way, we can use java to grab the link to Baidu LOGO.
Okay, although I spent a lot of time talking about Baidu, the foundation needs to be laid solidly. Next time we will officially start Zhihu! ~
The above is the content of writing Java Zhihu crawler with zero basic knowledge. First, practice with Baidu homepage (3). For more related content, please pay attention to the PHP Chinese website (www.php.cn)!

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