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Can't split string in Java

I have trouble with the split function in Java. When I try to split a string with a regex "$"
String line = "Vu Quang Huy$2/11/1999$Ha Noi$Nam$CNTT$1.2$12$10000.0";
String[] properties = line.split("$");
It doesn't do any thing. The properties at index 0 is the same as the original string
System.out.println(properties[0]);
And it shows
Vu Quang Huy$2/11/1999$Ha Noi$Nam$CNTT$1.2$12$10000.0
Can anyone help me with this problem? Thanks in advance!

$ in regex means "the end of a string", use \$ instead.
And, you have to escape the '\' as well, so you have to write it like this
String[] properties = line.split("\\$");

java.util.regex.PatternSyntaxException - when using split("\\");

I'm solving this problem in my own way. I'm trying to split the file path into Drive, folders, and file name, all into an array.
Complete class. (Github)
The problem:
String regex = "\\";
String [] divisions = path.split (regex);
This gives me an java.util.regex.PatternSyntaxException. I looked up the wiki and found [\b]
String regex = "[\b]";
String [] divisions = path.split (regex);
This doesn't work. It doesn't throw an exception, nor does it split my file path based on backspace.
Input:
► Enter path --
C:\User\Admin\NekedGaben.jpg
Output:
→ Path = C:\User\Admin\NekedGaben.jpg
→ File name = C:\User\Admin\NekedGaben
→ Extension = .jpg
My questions:
Why does "\\" throw an exception, while "[\b]" doesn't?
Why doesn't the split() split the Path string?

You should use double escaping in Java regex, i.e.:
String regex = "\\\\";
Or use static Pattern.quote(String) method:
String regex = Pattern.quote("\\");

Because \b is a single character, the compiler knows it, they're friends.
However backslash (\) is represented by \\ in Java, and \ is invalid regex, in order to escape it, you should use:
\\\\
↓ ↓
escaping
Solution:
Escape it as shown above
Don't escape, let Pattern#quote handle this for you

conditional replaceAll java

I have html code with img src tags pointing to urls. Some have mysite.com/myimage.png as src others have mysite.com/1234/12/12/myimage.png. I want to replace these urls with a cache file path. Im looking for something like this.
String website = "mysite.com"
String text = webContent.replaceAll(website+ "\\d{4}\\/\\d{2}\\/\\d{2}", String.valueOf(cacheDir));
This code however does not work when the url does not have the extra date stamp at the end. Does anyone know how i might achieve this? Thanks!

Try this one
mysite\.com/(\d{4}/\d{2}/\d{2}/)?
here ? means zero or more occurance
Note: use escape character \. for dot match because .(dot) is already used in regex
Sample code :
String[] webContents = new String[] { "mysite.com/myimage.png",
"mysite.com/1234/12/12/myimage.png" };
for (String webContent : webContents) {
String text = webContent.replaceAll("mysite\\.com/(\\d{4}/\\d{2}/\\d{2}/)?",
String.valueOf("mysite.com/abc/"));
System.out.println(text);
}
output:
mysite.com/abc/myimage.png
mysite.com/abc/myimage.png

You are missing a forward slash between the website.com and the first 4 digits.
String text = webContent.replaceAll(Pattern.quote(website) + "/\\d{4}\\/\\d{2}\\/\\d{2}", String.valueOf(cacheDir));
I'd also recommend using a literal for your website.com value (the Pattern.quote part).
Finally you are also missing the last forward slash after the last two digits so it won't be replaced, but that may be on purpose...

Try:
String text = webContent.replaceAll("(?<="+website+")(.*)(?=\\/)",
String.valueOf(cacheDir));

Java regex for Windows file path

I'm trying to build a Java regex to search a .txt file for a Windows formatted file path, however, due to the file path containing literal backslashes, my regex is failing.
The .txt file contains the line:
C\Windows\SysWOW64\ntdll.dll
However, some of the filenames in the text file are formatted like this:
C\Windows\SysWOW64\ntdll.dll (some developer stuff here...)
So I'm unable to use String.equals
To match this line, I'm using the regex:
filename = "C\\Windows\\SysWOW64\\ntdll.dll"
read = BufferedReader.readLine();
if (Pattern.compile(Pattern.quote(filename), Pattern.CASE_INSENSITIVE).matcher(read).find()) {
I've tried escaping the literal backslashes, using the replace method, i.e:
filename.replace("\\", "\\\\");
However, this is failing to find, I'm guessing this is because I need to further escape the backslashes after the Pattern has been built, I'm thinking I might need to escape upto an additional four backslashes, i.e:
Pattern.replaceAll("\\\\", "\\\\\\\\");
However, each time I try, the pattern doesn't get matched. I'm certain it's a problem with the backslashes, but I'm not sure where to do the replacement, or if there's a better way of building the pattern.
I think the problem is further being compounded as the replaceAll method also uses a regex, with means the pattern will have it's own backslashes in there, to deal with the case insensitivity.
Any input or advice would be appreciated.
Thanks

Seems like you're attempting to to a direct comparison of String against another. For exact matches, you could do (
if (read.equalsIgnoreCase(filename)) {
of simply
if (read.startsWith(filename)) {

Try this :
While reading each line from the file, replace '\' by '\\'.
Then :
String lLine = "C\\Windows\\SysWOW64\\ntdll.dll";
Pattern lPattern = Pattern.compile("C\\\\Windows\\\\SysWOW64\\\\ntdll\\.dll");
Matcher lMatcher = lPattern.matcher(lLine);
if(lMatcher.find()) {
System.out.println(lMatcher.group());
}
lLine = "C\\Windows\\SysWOW64\\ntdll.dll (some developer stuff here...)";
lMatcher = lPattern.matcher(lLine);
if(lMatcher.find()) {
System.out.println(lMatcher.group());
}

The correct usage will be:
String filename = "C\\Windows\\SysWOW64\\ntdll.dll";
String file = filename.replace('\\', ' ');

Replace "\\" with "/" in Java

I am trying to replace '\\'with '/' in java(Android) and this does not seem to work!
String rawPath = filePath.replace("\\\\", "/");
What is wrong with this ? I have escaped "\" and tried escaping '/' but to no use. Nothing happens to the original string.
filePath = abc\\xyz(not after escaping two \\, the original string is with two \\)
rawPath = abc \ xyz
expected = abc/xyz
Whats the correct way of doing this? (Another Windows file to Android path conversion prob)

When using String.replace(String, String) the backslash doesn't need to be escaped twice (thats when using replaceAll - it deals with regex). So:
String rawPath = filePath.replace("\\", "/");
Or using char version:
String rawPath = filePath.replace('\\', '/');

You do not need the quad-druple escape,
\\\\
, just simply
\\
.

escape with single slash should be enough. Following is working fine for me.
String rawPath = filePath.replace("\\", "/");

public static void main(String[] args) {
String s = "foo\\\\bar";
System.out.println(s);
System.out.println(s.replace("\\\\", "/"));
}
will print
foo\\bar
foo/bar

If you want to replace a sequence of 2 backslashes in your original string with a single forward slash, this should work:
String filePath = "abc\\\\xyz";
String rawPath = filePath.replace("\\\\", "/");
System.out.println(filePath);
System.out.println(rawPath);
outputs:
abc\\xyz
abc/xyz

Do you really have two backslashes in the String in the first place? That only appears in Java source code. At runtime there will only be one backslash. So the task reduces to changing backslashes to forward slashes (why?). For which you need a regex if you are using replaceAll(), which would require four of them: two for the compiler, and two for the regex, but you aren't using that, you are using replace(), which isn't a regex, so you only need two, one for the compiler and one for itself.
Why are you doing this? It is never necessary to use a backslash in a File path in Java at all, and it is also never necessary to translate them to / unless you are doing URL-like things with them, in which case there are File.toURI() methods and URI and URL classes for that.

Here is a very small method to get the desktop path and show you how to replace them in the return statement.
public static String getDesktopPath() {
String desktopPath = System.getProperty("user.home") + "/Desktop";
return desktopPath.replace("\\", "/");
}