使用Java和Regex帮助从html标签中提取文本 [英] Help extracting text from html tag with Java and Regex
问题描述
我想使用Regex从html文件中提取一些文本。我正在学习正则表达式，我仍然无法理解这一切。我有一段代码，它提取了< body> 和< / body> 之间包含的所有文本：
public class Harn2 {
public static void main（String [] args）throws IOException {
String toMatch = readFile（）;
// Pattern pattern = Pattern.compile（。*？< body。*？>（。*？）< / body>。*？）;这个工作正常
Pattern pattern = Pattern.compile（。*？< table class = \claroTable\。*？>（。*？）< / table>。*？ ）; //我希望这个工作
Matcher匹配器= pattern.matcher（toMatch）;
if（matcher.matches（））{
System.out.println（matcher.group（1））;
$ b private static String readFile（）{
try {
//打开文件第一个
//命令行参数
FileInputStream fstream = new FileInputStream（user.html）;
//获取DataInputStream的对象
DataInputStream in = new DataInputStream（fstream）;
BufferedReader br = new BufferedReader（new InputStreamReader（in））;
String strLine = null;
//读取文件行按行
while（br.readLine（）！= null）{
//打印控制台上的内容
//System.out.println （strLine中）;
strLine + = br.readLine（）;
}
//关闭输入流
in.close（）;
返回strLine;
} catch（Exception e）{//捕获异常（如果有）
System.err.println（Error：+ e.getMessage（））;
return;
$ / code $ / pre
但现在我想提取标签之间的文本：
< table class =claroTable> 和< /所以我用。*？< table class = \claroTable替换了我的正则表达式字符串\。*？>（。*？）< / table>。*？
我也尝试了
。* ？< table class = \claroTable\>（。*？）< / table>。*？
但它不起作用，不明白为什么。 html文件中只有一个表格，但在javascript代码中出现table：... dataTables.js ...可能是错误原因吗？
预先感谢您的帮助，
编辑：html文本以extranct为例：
< body>
.....
< table class =claroTable>
< td>< th>一些数据和许多标签< / td>
.....
< / table>
我想提取的是< table class =之间的任何内容claroTable>> 和< / table>
解决方案您可以使用 JSoup解析器完成此操作： File file = new File（path / to / your / file.html）;
String charSet =ISO-8859-1;
字符串innerHtml = Jsoup.parse（file，charSet）.select（body）。html（）;
是的，您 can 永远不要这么容易。
更新：你的正则表达式模式的主要问题是你缺少 DOTALL flag：
Pattern pattern = Pattern.compile（。*？< body。*？>（。*？ ）LT /体> *，Pattern.DOTALL）？;
如果你只是想要内容指定的表格标签，你可以这样做： p>
String tableTag =
Pattern.compile（。*？< table。*？claroTable。*？>（ 。*？）< / table>。*？，Pattern.DOTALL）
.matcher（html）
.replaceFirst（$ 1）;
（更新：现在只返回表格标签的内容，而不是表格标签本身） p>
I would like to extract some text from an html file using Regex. I am learning regex and I still have trouble understanding it all. I have a code which extracts all the text included betweeen <body> and </body> here it is:
public class Harn2 {
public static void main(String[] args) throws IOException{
String toMatch=readFile();
//Pattern pattern=Pattern.compile(".*?<body.*?>(.*?)</body>.*?"); this one works fine
Pattern pattern=Pattern.compile(".*?<table class=\"claroTable\".*?>(.*?)</table>.*?"); //I want this one to work
Matcher matcher=pattern.matcher(toMatch);
if(matcher.matches()) {
System.out.println(matcher.group(1));
}
}
private static String readFile() {
try{
// Open the file that is the first
// command line parameter
FileInputStream fstream = new FileInputStream("user.html");
// Get the object of DataInputStream
DataInputStream in = new DataInputStream(fstream);
BufferedReader br = new BufferedReader(new InputStreamReader(in));
String strLine = null;
//Read File Line By Line
while (br.readLine() != null) {
// Print the content on the console
//System.out.println (strLine);
strLine+=br.readLine();
}
//Close the input stream
in.close();
return strLine;
}catch (Exception e){//Catch exception if any
System.err.println("Error: " + e.getMessage());
return "";
}
}
}
Well it works fine like this but now I would like to extract the text between the tag:
<table class="claroTable"> and </table>
So I replace my regex string by ".*?<table class=\"claroTable\".*?>(.*?)</table>.*?"
I have also tried
".*?<table class=\"claroTable\">(.*?)</table>.*?"
but it doesn't work and I don't understand why. There is only one table in the html file but there is an occurence of "table" in a javascript code : "...dataTables.js..." could that be the reason for the mistake?
Thank you in advance for helping me,
EDIT: the html text to extranct is something like:
<body>
.....
<table class="claroTable">
<td><th>some data and manya many tags </td>
.....
</table>
What I would like to extract is anything between <table class="claroTable"> and </table>
解决方案 Here's how you can do it with the JSoup parser:
File file = new File("path/to/your/file.html");
String charSet = "ISO-8859-1";
String innerHtml = Jsoup.parse(file,charSet).select("body").html();
Yes, you can also somehow do it with regex, but it will never be this easy.
Update: The main problem with your regex pattern is that you are missing the DOTALL flag:
Pattern pattern=Pattern.compile(".*?<body.*?>(.*?)</body>.*?",Pattern.DOTALL);
And if you just want the specified table tag with contents, you can do something like this:
String tableTag =
Pattern.compile(".*?<table.*?claroTable.*?>(.*?)</table>.*?",Pattern.DOTALL)
.matcher(html)
.replaceFirst("$1");
(Updated: now returns the contents of the table tag only, not the table tag itself)
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