[英]How do I preserve line breaks when using jsoup to convert html to plain text?
我有以下代碼：
public class NewClass {
public String noTags(String str){
return Jsoup.parse(str).text();
}
public static void main(String args[]) {
String strings="<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.0 Transitional//EN \">" +
"<HTML> <HEAD> <TITLE></TITLE> <style>body{ font-size: 12px;font-family: verdana, arial, helvetica, sans-serif;}</style> </HEAD> <BODY><p><b>hello world</b></p><p><br><b>yo</b> <a href=\"http://google.com\">googlez</a></p></BODY> </HTML> ";
NewClass text = new NewClass();
System.out.println((text.noTags(strings)));
}
結果是：
hello world yo googlez
但我想打破界限：
hello world
yo googlez
我已經看過jsoup的TextNode＃getWholeText（），但是我不知道如何使用它。
如果我解析的標記中有一個<br> ，如何在我得到的輸出中換行？
保留換行符的真正解決方案應該是這樣的：
public static String br2nl(String html) {
if(html==null)
return html;
Document document = Jsoup.parse(html);
document.outputSettings(new Document.OutputSettings().prettyPrint(false));//makes html() preserve linebreaks and spacing
document.select("br").append("\\n");
document.select("p").prepend("\\n\\n");
String s = document.html().replaceAll("\\\\n", "\n");
return Jsoup.clean(s, "", Whitelist.none(), new Document.OutputSettings().prettyPrint(false));
}
滿足以下要求：
Jsoup.clean(unsafeString, "", Whitelist.none(), new OutputSettings().prettyPrint(false));
我們在這里使用這種方法：
public static String clean(String bodyHtml,
String baseUri,
Whitelist whitelist,
Document.OutputSettings outputSettings)
通過將其傳遞給Whitelist.none()我們確保刪除所有HTML。
通過傳遞new OutputSettings().prettyPrint(false)我們確保輸出未重新格式化並保留了換行符。
用
Jsoup.parse("A\nB").text();
你有輸出
"A B"
並不是
A
B
為此，我正在使用：
descrizione = Jsoup.parse(html.replaceAll("(?i)<br[^>]*>", "br2n")).text();
text = descrizione.replaceAll("br2n", "\n");
使用jsoup嘗試一下：
public static String cleanPreserveLineBreaks(String bodyHtml) {
// get pretty printed html with preserved br and p tags
String prettyPrintedBodyFragment = Jsoup.clean(bodyHtml, "", Whitelist.none().addTags("br", "p"), new OutputSettings().prettyPrint(true));
// get plain text with preserved line breaks by disabled prettyPrint
return Jsoup.clean(prettyPrintedBodyFragment, "", Whitelist.none(), new OutputSettings().prettyPrint(false));
}
在Jsoup v1.11.2上，我們現在可以使用Element.wholeText() 。
示例代碼：
String cleanString = Jsoup.parse(htmlString).wholeText();
user121196's 答案仍然有效。 但是wholeText()保留文本的對齊方式。
您可以遍歷給定的元素
public String convertNodeToText(Element element)
{
final StringBuilder buffer = new StringBuilder();
new NodeTraversor(new NodeVisitor() {
boolean isNewline = true;
@Override
public void head(Node node, int depth) {
if (node instanceof TextNode) {
TextNode textNode = (TextNode) node;
String text = textNode.text().replace('\u00A0', ' ').trim();
if(!text.isEmpty())
{
buffer.append(text);
isNewline = false;
}
} else if (node instanceof Element) {
Element element = (Element) node;
if (!isNewline)
{
if((element.isBlock() || element.tagName().equals("br")))
{
buffer.append("\n");
isNewline = true;
}
}
}
}
@Override
public void tail(Node node, int depth) {
}
}).traverse(element);
return buffer.toString();
}
而對於您的代碼
String result = convertNodeToText(JSoup.parse(html))
text = Jsoup.parse(html.replaceAll("(?i)<br[^>]*>", "br2n")).text();
text = descrizione.replaceAll("br2n", "\n");
如果html本身不包含“ br2n”，則可以使用
所以，
text = Jsoup.parse(html.replaceAll("(?i)<br[^>]*>", "<pre>\n</pre>")).text();
工作更可靠，更輕松。
使用jsoup嘗試一下：
doc.outputSettings(new OutputSettings().prettyPrint(false));
//select all <br> tags and append \n after that
doc.select("br").after("\\n");
//select all <p> tags and prepend \n before that
doc.select("p").before("\\n");
//get the HTML from the document, and retaining original new lines
String str = doc.html().replaceAll("\\\\n", "\n");
使用textNodes()獲取文本節點列表。 然后使用\\n作為分隔符將它們連接起來。 這是我使用的一些scala代碼，java端口應該很簡單：
val rawTxt = doc.body().getElementsByTag("div").first.textNodes()
.asScala.mkString("<br />\n")
這是我將html轉換為文本的版本（實際上是user121196答案的修改版本）。
這不僅保留了換行符，還格式化了文本並刪除了過多的換行符，HTML轉義符號，並且HTML會帶來更好的結果（就我而言，我是從郵件中收到的）。
它最初是用Scala編寫的，但是您可以輕松地將其更改為Java
def html2text( rawHtml : String ) : String = {
val htmlDoc = Jsoup.parseBodyFragment( rawHtml, "/" )
htmlDoc.select("br").append("\\nl")
htmlDoc.select("div").prepend("\\nl").append("\\nl")
htmlDoc.select("p").prepend("\\nl\\nl").append("\\nl\\nl")
org.jsoup.parser.Parser.unescapeEntities(
Jsoup.clean(
htmlDoc.html(),
"",
Whitelist.none(),
new org.jsoup.nodes.Document.OutputSettings().prettyPrint(true)
),false
).
replaceAll("\\\\nl", "\n").
replaceAll("\r","").
replaceAll("\n\\s+\n","\n").
replaceAll("\n\n+","\n\n").
trim()
}
根據其他答案和對該問題的評論，似乎大多數來這里的人們都在尋找一種通用的解決方案，該解決方案將提供HTML文檔格式良好的純文本表示形式。 我知道我曾經
幸運的是，JSoup已經提供了一個有關如何實現此目標的非常全面的示例： HtmlToPlainText.java
可以很容易地根據您的偏好調整示例FormattingVisitor並處理大多數塊元素和換行。
為了避免鏈接腐爛，下面是Jonathan Hedley的完整解決方案：
package org.jsoup.examples;
import org.jsoup.Jsoup;
import org.jsoup.helper.StringUtil;
import org.jsoup.helper.Validate;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.nodes.Node;
import org.jsoup.nodes.TextNode;
import org.jsoup.select.Elements;
import org.jsoup.select.NodeTraversor;
import org.jsoup.select.NodeVisitor;
import java.io.IOException;
/**
* HTML to plain-text. This example program demonstrates the use of jsoup to convert HTML input to lightly-formatted
* plain-text. That is divergent from the general goal of jsoup's .text() methods, which is to get clean data from a
* scrape.
* <p>
* Note that this is a fairly simplistic formatter -- for real world use you'll want to embrace and extend.
* </p>
* <p>
* To invoke from the command line, assuming you've downloaded the jsoup jar to your current directory:</p>
* <p><code>java -cp jsoup.jar org.jsoup.examples.HtmlToPlainText url [selector]</code></p>
* where <i>url</i> is the URL to fetch, and <i>selector</i> is an optional CSS selector.
*
* @author Jonathan Hedley, jonathan@hedley.net
*/
public class HtmlToPlainText {
private static final String userAgent = "Mozilla/5.0 (jsoup)";
private static final int timeout = 5 * 1000;
public static void main(String... args) throws IOException {
Validate.isTrue(args.length == 1 || args.length == 2, "usage: java -cp jsoup.jar org.jsoup.examples.HtmlToPlainText url [selector]");
final String url = args[0];
final String selector = args.length == 2 ? args[1] : null;
// fetch the specified URL and parse to a HTML DOM
Document doc = Jsoup.connect(url).userAgent(userAgent).timeout(timeout).get();
HtmlToPlainText formatter = new HtmlToPlainText();
if (selector != null) {
Elements elements = doc.select(selector); // get each element that matches the CSS selector
for (Element element : elements) {
String plainText = formatter.getPlainText(element); // format that element to plain text
System.out.println(plainText);
}
} else { // format the whole doc
String plainText = formatter.getPlainText(doc);
System.out.println(plainText);
}
}
/**
* Format an Element to plain-text
* @param element the root element to format
* @return formatted text
*/
public String getPlainText(Element element) {
FormattingVisitor formatter = new FormattingVisitor();
NodeTraversor traversor = new NodeTraversor(formatter);
traversor.traverse(element); // walk the DOM, and call .head() and .tail() for each node
return formatter.toString();
}
// the formatting rules, implemented in a breadth-first DOM traverse
private class FormattingVisitor implements NodeVisitor {
private static final int maxWidth = 80;
private int width = 0;
private StringBuilder accum = new StringBuilder(); // holds the accumulated text
// hit when the node is first seen
public void head(Node node, int depth) {
String name = node.nodeName();
if (node instanceof TextNode)
append(((TextNode) node).text()); // TextNodes carry all user-readable text in the DOM.
else if (name.equals("li"))
append("\n * ");
else if (name.equals("dt"))
append(" ");
else if (StringUtil.in(name, "p", "h1", "h2", "h3", "h4", "h5", "tr"))
append("\n");
}
// hit when all of the node's children (if any) have been visited
public void tail(Node node, int depth) {
String name = node.nodeName();
if (StringUtil.in(name, "br", "dd", "dt", "p", "h1", "h2", "h3", "h4", "h5"))
append("\n");
else if (name.equals("a"))
append(String.format(" <%s>", node.absUrl("href")));
}
// appends text to the string builder with a simple word wrap method
private void append(String text) {
if (text.startsWith("\n"))
width = 0; // reset counter if starts with a newline. only from formats above, not in natural text
if (text.equals(" ") &&
(accum.length() == 0 || StringUtil.in(accum.substring(accum.length() - 1), " ", "\n")))
return; // don't accumulate long runs of empty spaces
if (text.length() + width > maxWidth) { // won't fit, needs to wrap
String words[] = text.split("\\s+");
for (int i = 0; i < words.length; i++) {
String word = words[i];
boolean last = i == words.length - 1;
if (!last) // insert a space if not the last word
word = word + " ";
if (word.length() + width > maxWidth) { // wrap and reset counter
accum.append("\n").append(word);
width = word.length();
} else {
accum.append(word);
width += word.length();
}
}
} else { // fits as is, without need to wrap text
accum.append(text);
width += text.length();
}
}
@Override
public String toString() {
return accum.toString();
}
}
}
對於更復雜的HTML，上述解決方案均無法正常工作。 我能夠成功進行轉換，同時保留以下換行符：
Document document = Jsoup.parse(myHtml);
String text = new HtmlToPlainText().getPlainText(document);
（版本1.10.3）
嘗試這個：
public String noTags(String str){
Document d = Jsoup.parse(str);
TextNode tn = new TextNode(d.body().html(), "");
return tn.getWholeText();
}
/**
* Recursive method to replace html br with java \n. The recursive method ensures that the linebreaker can never end up pre-existing in the text being replaced.
* @param html
* @param linebreakerString
* @return the html as String with proper java newlines instead of br
*/
public static String replaceBrWithNewLine(String html, String linebreakerString){
String result = "";
if(html.contains(linebreakerString)){
result = replaceBrWithNewLine(html, linebreakerString+"1");
} else {
result = Jsoup.parse(html.replaceAll("(?i)<br[^>]*>", linebreakerString)).text(); // replace and html line breaks with java linebreak.
result = result.replaceAll(linebreakerString, "\n");
}
return result;
}
通過與所涉及的html一起調用而使用，該html包含br以及希望用作臨時換行符的任何字符串。 例如：
replaceBrWithNewLine(element.html(), "br2n")
遞歸將確保您用作換行符/換行符占位符的字符串實際上不會出現在源html中，因為它將一直添加“ 1”，直到在html中找不到linkbreaker占位符字符串為止。 它不會出現Jsoup.clean方法似乎帶有特殊字符的格式問題。
根據user121196和Green Beret的select和<pre>回答，唯一適用於我的解決方案是：
org.jsoup.nodes.Element elementWithHtml = ....
elementWithHtml.select("br").append("<pre>\n</pre>");
elementWithHtml.select("p").prepend("<pre>\n\n</pre>");
elementWithHtml.text();
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