在Java中将HTML转换为纯文本

Question

我需要将HTML转换为纯文本.我对格式化的唯一要求是在纯文本中保留新行.新行不仅应显示在<br>其他标签的情况下,例如<tr/>,也应显示</p>新行.

用于测试的示例HTML页面是:

• http://www.particle.kth.se/~lindsey/JavaCourse/Book/Part1/Java/Chapter09/scannerConsole.html
• http://www.javadb.com/write-to-file-using-bufferedwriter

请注意,这些只是随机网址.

我已经尝试了在这个StackOverflow问题的答案中提到的各种库(JSoup,Javax.swing,Apache utils)来将HTML转换为纯文本.

使用JSoup的示例:

public class JSoupTest {

 @Test
 public void SimpleParse() {
  try {
   Document doc = Jsoup.connect("http://www.particle.kth.se/~lindsey/JavaCourse/Book/Part1/Java/Chapter09/scannerConsole.html").get();
   System.out.print(doc.text());

  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
 }
}

HTMLEditorKit示例:

import javax.swing.text.html.*;
import javax.swing.text.html.parser.*;

public class Html2Text extends HTMLEditorKit.ParserCallback {
 StringBuffer s;

 public Html2Text() {}

 public void parse(Reader in) throws IOException {
   s = new StringBuffer();
   ParserDelegator delegator = new ParserDelegator();
   // the third parameter is TRUE to ignore charset directive
   delegator.parse(in, this, Boolean.TRUE);
 }

 public void handleText(char[] text, int pos) {
   s.append(text);
 }

 public String getText() {
   return s.toString();
 }

 public static void main (String[] args) {
   try {
     // the HTML to convert
    URL  url = new URL("http://www.javadb.com/write-to-file-using-bufferedwriter");
    URLConnection conn = url.openConnection();
    BufferedReader reader = new BufferedReader(new InputStreamReader(url.openStream()));
    String inputLine;
    String finalContents = "";
    while ((inputLine = reader.readLine()) != null) {
     finalContents += "\n" + inputLine.replace("<br", "\n<br");
    }
    BufferedWriter writer = new BufferedWriter(new FileWriter("samples/testHtml.html"));
    writer.write(finalContents);
    writer.close();

     FileReader in = new FileReader("samples/testHtml.html");
     Html2Text parser = new Html2Text();
     parser.parse(in);
     in.close();
     System.out.println(parser.getText());
   }
   catch (Exception e) {
     e.printStackTrace();
   }
 }
}

Answer 1

让解析器将文本内容和换行符附加到StringBuilder.

final StringBuilder sb = new StringBuilder();
HTMLEditorKit.ParserCallback parserCallback = new HTMLEditorKit.ParserCallback() {
    public boolean readyForNewline;

    @Override
    public void handleText(final char[] data, final int pos) {
        String s = new String(data);
        sb.append(s.trim());
        readyForNewline = true;
    }

    @Override
    public void handleStartTag(final HTML.Tag t, final MutableAttributeSet a, final int pos) {
        if (readyForNewline && (t == HTML.Tag.DIV || t == HTML.Tag.BR || t == HTML.Tag.P)) {
            sb.append("\n");
            readyForNewline = false;
        }
    }

    @Override
    public void handleSimpleTag(final HTML.Tag t, final MutableAttributeSet a, final int pos) {
        handleStartTag(t, a, pos);
    }
};
new ParserDelegator().parse(new StringReader(html), parserCallback, false);

Answer 2

我猜你可以使用 ParserCallback。

您需要添加代码来支持需要特殊处理的标签。有：

1. 处理开始标签
2. 处理结束标签
3. 处理简单标签

回调应该允许您检查要监视的标签，然后将换行符附加到缓冲区。