正则表达式模式以匹配某些URL

Question

I have a large text and I only want to use certain information from it. The text looks like this:

Some random text here
http://xxx-f.xxx.net/i/xx/open/xxxx/1370235-005A/EPISOD-1370235-005A-xxx_,892,144,252,360,540,1584,xxxx,.mp4.csmil/index_0_av.m3u8
More random text here
http://xxx-f.xxx.net/i/xx/open/xxxx/1370235-005A/EPISOD-1370235-005A-xxx_,892,144,252,360,540,1584,xxxx,.mp4.csmil/index_1_av.m3u8
More random text here
http://xxx-f.xxx.net/i/xx/open/xxxx/1370235-005A/EPISOD-1370235-005A-xxx_,892,144,252,360,540,1584,xxxx,.mp4.csmil/index_2_av.m3u8
More random text here
http://xxx-f.xxx.net/i/xx/open/xxxx/1370235-005A/EPISOD-1370235-005A-xxx_,892,144,252,360,540,1584,xxxx,.mp4.csmil/index_3_av.m3u8

I only want the http text. There are several of them in the text but I only need one of them. The regular expression should be "starts with http and ends with .m3u8".

I looked at the glossary of all the different expression but it is very confusing to me. I tried "/^(https?:\\/\\/)?([\\da-z\\.-]+)\\.([az\\.]{12,30})([\\/\\w \\.-]*)*\\/?$/" as my pattern. But is that enough?

All help is appreciated. Thank you.

Answer 1

Assuming your text is line-separated at every line representation in your example, here's a snippet that will work:

String text = 
"Some random text here" +
System.getProperty("line.separator") +
"http://xxx-f.xxx.net/i/xx/open/xxxx/1370235-005A/EPISOD-1370235-005A-xxx_,892,144,252,360,540,1584,xxxx,.mp4.csmil/index_0_av.m3u8" +
System.getProperty("line.separator") +
"More random text here" +
System.getProperty("line.separator") +
"http://xxx-f.xxx.net/i/xx/open/xxxx/1370235-005A/EPISOD-1370235-005A-xxx_,892,144,252,360,540,1584,xxxx,.mp4.csmil/index_0_av.m3u8" +
System.getProperty("line.separator") +
// removed some for brevity
"More random text here" +
System.getProperty("line.separator") +
// added counter-example ending with "NOPE"
"http://xxx-f.xxx.net/i/xx/open/xxxx/1370235-005A/EPISOD-1370235-005A-xxx_,892,144,252,360,540,1584,xxxx,.mp4.csmil/index_0_av.NOPE";

// Multi-line pattern:
//                           ┌ line starts with http
//                           |    ┌ any 1+ character reluctantly quantified
//                           |    |  ┌ dot escape
//                           |    |  |  ┌ ending text
//                           |    |  |  |   ┌ end of line marker
//                           |    |  |  |   |
Pattern p = Pattern.compile("^http.+?\\.m3u8$", Pattern.MULTILINE);
Matcher m = p.matcher(text);
while (m.find()) {
    System.out.println(m.group());
}

Output

http://xxx-f.xxx.net/i/xx/open/xxxx/1370235-005A/EPISOD-1370235-005A-xxx_,892,144,252,360,540,1584,xxxx,.mp4.csmil/index_0_av.m3u8
http://xxx-f.xxx.net/i/xx/open/xxxx/1370235-005A/EPISOD-1370235-005A-xxx_,892,144,252,360,540,1584,xxxx,.mp4.csmil/index_0_av.m3u8

Edit

For a refined "filter" by the "index_x" file of the URL, you can simply add it in the Pattern between the protocol and ending of the line, eg:

Pattern.compile("^http.+?index_0.+?\\.m3u8$", Pattern.MULTILINE);

Answer 2

我没有测试它，但这应该可以解决问题：

^(http:\/\/.*\.m3u8)

Answer 3

It is the answer of @capnibishop, but with a little change.

^(http://).*(/index_1)[^/]*\.m3u8$

Added the missing "$" sign at the end. This ensures it matches

http://something.m3u8

and not

http://something.m3u81

Added the condition to match index_1 at the end of the line, which means it wil match:

http://something/index_1_something_else.m3u8

and not

http://something/index_1/something_else.m3u8