将网站内容读入字符串 [英] Reading website's contents into string

问题描述

目前我正在开发一个可用于读取网址指定网站内容的类。我只是用 java.io 和 java.net 开始我的冒险，所以我需要咨询我的设计。

Currently I'm working on a class that can be used to read the contents of the website specified by the url. I'm just beginning my adventures with java.io and java.net so I need to consult my design.

用法：

TextURL url = new TextURL(urlString);
String contents = url.read();

我的代码：

package pl.maciejziarko.util;

import java.io.*;
import java.net.*;

public final class TextURL
{
    private static final int BUFFER_SIZE = 1024 * 10;
    private static final int ZERO = 0;
    private final byte[] dataBuffer = new byte[BUFFER_SIZE];
    private final URL urlObject;

    public TextURL(String urlString) throws MalformedURLException
    {
        this.urlObject = new URL(urlString);
    }

    public String read() 
    {
        final StringBuilder sb = new StringBuilder();

        try
        {
            final BufferedInputStream in =
                    new BufferedInputStream(urlObject.openStream());

            int bytesRead = ZERO;

            while ((bytesRead = in.read(dataBuffer, ZERO, BUFFER_SIZE)) >= ZERO)
            {
                sb.append(new String(dataBuffer, ZERO, bytesRead));
            }
        }
        catch (UnknownHostException e)
        {
            return null;
        }
        catch (IOException e)
        {
            return null;
        }

        return sb.toString();
    }

    //Usage:
    public static void main(String[] args)
    {
        try
        {
            TextURL url = new TextURL("http://www.flickr.com/explore/interesting/7days/");
            String contents = url.read();

            if (contents != null)
                System.out.println(contents);
            else
                System.out.println("ERROR!");
        }
        catch (MalformedURLException e)
        {
            System.out.println("Check you the url!");
        }
    }
}

我的问题是：
这是实现我想要的好方法吗？还有更好的解决方案吗？

My question is: Is it a good way to achieve what I want? Are there any better solutions?

我特别不喜欢 sb.append（new String（dataBuffer，ZERO，bytesRead））; 但我无法以不同的方式表达它。每次迭代都创建一个新的String是否合适？我想没有。

I particularly didn't like sb.append(new String(dataBuffer, ZERO, bytesRead)); but I wasn't able to express it in a different way. Is it good to create a new String every iteration? I suppose no.

还有其他任何弱点吗？

提前致谢！

推荐答案

考虑使用 URLConnection 。此外，您可能希望利用 IOUtils来自 Apache Commons IO 的 ，以便更轻松地阅读字符串。例如：

Consider using URLConnection instead. Furthermore you might want to leverage IOUtils from Apache Commons IO to make the string reading easier too. For example:

URL url = new URL("http://www.example.com/");
URLConnection con = url.openConnection();
InputStream in = con.getInputStream();
String encoding = con.getContentEncoding();  // ** WRONG: should use "con.getContentType()" instead but it returns something like "text/html; charset=UTF-8" so this value must be parsed to extract the actual encoding
encoding = encoding == null ? "UTF-8" : encoding;
String body = IOUtils.toString(in, encoding);
System.out.println(body);

如果您不想使用 IOUtils 我可能会在以下内容上重写该行：

If you don't want to use IOUtils I'd probably rewrite that line above something like:

ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buf = new byte[8192];
int len = 0;
while ((len = in.read(buf)) != -1) {
    baos.write(buf, 0, len);
}
String body = new String(baos.toByteArray(), encoding);

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