Java Web Crawler库

问题描述

我想为实验制作一个基于Java的网络爬虫。我听说如果这是你第一次使用Java制作一个Web爬虫是可行的方法。但是，我有两个重要问题。

I wanted to make a Java based web crawler for an experiment. I heard that making a Web Crawler in Java was the way to go if this is your first time. However, I have two important questions.

1. 我的程序如何访问或连接到网页？请简要说明一下。 （我理解从硬件到软件的抽象层的基础知识，这里我对Java抽象感兴趣）

1. How will my program 'visit' or 'connect' to web pages? Please give a brief explanation. (I understand the basics of the layers of abstraction from the hardware up to the software, here I am interested in the Java abstractions)

我应该使用哪些库？我想我需要一个用于连接网页的库，一个用于HTTP / HTTPS协议的库，以及一个用于HTML解析的库。

What libraries should I use? I would assume I need a library for connecting to web pages, a library for HTTP/HTTPS protocol, and a library for HTML parsing.

推荐答案

这是您的程序访问或连接网页的方式。

This is How your program 'visit' or 'connect' to web pages.

    URL url;
    InputStream is = null;
    DataInputStream dis;
    String line;

    try {
        url = new URL("http://stackoverflow.com/");
        is = url.openStream();  // throws an IOException
        dis = new DataInputStream(new BufferedInputStream(is));

        while ((line = dis.readLine()) != null) {
            System.out.println(line);
        }
    } catch (MalformedURLException mue) {
         mue.printStackTrace();
    } catch (IOException ioe) {
         ioe.printStackTrace();
    } finally {
        try {
            is.close();
        } catch (IOException ioe) {
            // nothing to see here
        }
    }

这将下载html页面的来源。

This will download source of html page.

对于HTML解析，请参阅

For HTML parsing see this

另请查看和

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