search
HomeJavajavaTutorialWrite 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)!


Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
How does IntelliJ IDEA identify the port number of a Spring Boot project without outputting a log?How does IntelliJ IDEA identify the port number of a Spring Boot project without outputting a log?Apr 19, 2025 pm 11:45 PM

Start Spring using IntelliJIDEAUltimate version...

How to elegantly obtain entity class variable names to build database query conditions?How to elegantly obtain entity class variable names to build database query conditions?Apr 19, 2025 pm 11:42 PM

When using MyBatis-Plus or other ORM frameworks for database operations, it is often necessary to construct query conditions based on the attribute name of the entity class. If you manually every time...

How to use the Redis cache solution to efficiently realize the requirements of product ranking list?How to use the Redis cache solution to efficiently realize the requirements of product ranking list?Apr 19, 2025 pm 11:36 PM

How does the Redis caching solution realize the requirements of product ranking list? During the development process, we often need to deal with the requirements of rankings, such as displaying a...

How to safely convert Java objects to arrays?How to safely convert Java objects to arrays?Apr 19, 2025 pm 11:33 PM

Conversion of Java Objects and Arrays: In-depth discussion of the risks and correct methods of cast type conversion Many Java beginners will encounter the conversion of an object into an array...

How do I convert names to numbers to implement sorting and maintain consistency in groups?How do I convert names to numbers to implement sorting and maintain consistency in groups?Apr 19, 2025 pm 11:30 PM

Solutions to convert names to numbers to implement sorting In many application scenarios, users may need to sort in groups, especially in one...

E-commerce platform SKU and SPU database design: How to take into account both user-defined attributes and attributeless products?E-commerce platform SKU and SPU database design: How to take into account both user-defined attributes and attributeless products?Apr 19, 2025 pm 11:27 PM

Detailed explanation of the design of SKU and SPU tables on e-commerce platforms This article will discuss the database design issues of SKU and SPU in e-commerce platforms, especially how to deal with user-defined sales...

How to set the default run configuration list of SpringBoot projects in Idea for team members to share?How to set the default run configuration list of SpringBoot projects in Idea for team members to share?Apr 19, 2025 pm 11:24 PM

How to set the SpringBoot project default run configuration list in Idea using IntelliJ...

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

SublimeText3 English version

SublimeText3 English version

Recommended: Win version, supports code prompts!

mPDF

mPDF

mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

MinGW - Minimalist GNU for Windows

MinGW - Minimalist GNU for Windows

This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.

Atom editor mac version download

Atom editor mac version download

The most popular open source editor