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How to replace a given substring with "" from a given string?

I went through a couple of examples to replace a given sub-string from a given string with "" but could not achieve the result. The String is too long to post and it contains a sub-string which is as follows:-
/image/journal/article?img_id=24810&t=1475128689597
I want to replace this sub-string with "".Here the value of img_id and t can vary, so I would have to use regular expression. I tried with the following code:-
String regex="^/image/journal/article?img_id=([0-9])*&t=([0-9])*$";
content=content.replace(regex,"");
Here content is the original given string. But this code is actually not replacing anything from the content. So please help..any help would be appreciated .thanx in advance.

Use replaceAll works in nice way with regex
content=content.replaceAll("[0-9]*","");
Code
String content="/image/journal/article?img_id=24810&t=1475128689597";
content=content.replaceAll("[0-9]*","");
System.out.println(content);
Output :
/image/journal/article?img_id=&t=
Update : simple, might be little less cozy but easy one
String content="sas/image/journal/article?img_id=24810&t=1475128689597";
content=content.replaceAll("\\/image.*","");
System.out.println(content);
Output:
sas
If there is something more after t=1475128689597/?tag=343sdds and you want to retain ?tag=343sdds then use below
String content="sas/image/journal/article?img_id=24810&t=1475128689597/?tag=343sdds";
content=content.replaceAll("(\\/image.*[0-9]+[\\/])","");
System.out.println(content);
}
Output:
sas?tag=343sdds

If you're trying to replace the substring of the URL with two quotations like so:
/image/journal/article?img_id=""&t=""
Then you need to add escaped quotes \"\" inside your content assignment, edit your regex to only look for the numbers, and change it to replaceAll:
content=content.replaceAll(regex,"\"\"");

You can use Java regex Utility to replace your String with "" or (any desired String literal), based on given pattern (regex) as following:
String content = "ALPHA_/image/journal/article?img_id=24810&t=1475128689597_BRAVO";
String regex = "\\/image\\/journal\\/article\\?img_id=\\d+&t=\\d+";
Pattern pattern = Pattern.compile(regex);
Matcher matcher = pattern.matcher(content);
if (matcher.find()) {
String replacement = matcher.replaceAll("PK");
System.out.println(replacement); // Will print ALPHA_PK_BRAVO
}

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));

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("\\", "/");
}

How to check and replace special character(\) contain in a String in java?

I have a String str=p2\7\2010 I want to check and replace if str.contains("\") then replace it into this("\\\\") instead of \. i am unable to do this in Java please give your little effort.

use String.replace():
if (str.contains("\\")) {
str = str.replace("\\", "\\\\");
}
You can also use String.replaceAll(), but it uses regular expressions and so is slower in such trivial case.
UPDATE:
Implementation of String.replace() is based on regular expressions as well, but compiled in Pattern.LITERAL mode.

str.contains("\"") matches string that have a " in them.
What you probably want is str.replaceAll("\\", "\\\\")
Additionally; for checking if it contains a \ you'd need str.contains("\\"), since the \ is a special character it has to be escaped.

Try this,
String newString = oldString.replace("/", "//");
or try pattern method,
Pattern pattern = Pattern.compile("/");
Matcher matcher = pattern.matcher("abc/xyz");
String output = matcher.replaceAll("//");

Replace backslashes in a string using Java/Groovy

Trying to get a simple string replace to work using a Groovy script. Tried various things, including escaping strings in various ways, but can't figure it out.
String file ="C:\\Test\\Test1\\Test2\\Test3\\"
String afile = file.toString() println
"original string: " + afile
afile.replace("\\\\", "/")
afile.replaceAll("\\\\", "/") println
"replaced string: " + afile
This code results in:
original string: C:\Test\Test1\Test2\Test3\
replaced string: C:\Test\Test1\Test2\Test3\
----------------------------
The answer, as inspired by Sorrow, looks like this:
// first, replace backslashes
String afile = file.toString().replaceAll("\\\\", "/")
// then, convert backslash to forward slash
String fixed = afile.replaceAll("//", "/")

replace returns a different string. In Java Strings cannot be modified, so you need to assign the result of replacing to something, and print that out.
String other = afile.replaceAll("\\\\", "/")
println "replaced string: " + other
Edited: as Neftas pointed in the comment, \ is a special character in regex and thus have to be escaped twice.

In Groovy you can't even write \\ - it is "an unsupported escape sequence". So, all answers I see here are incorrect.
If you mean one backslash, you should write \\\\. So, changing backslashes to normal slashes will look as:
scriptPath = scriptPath.replaceAll("\\\\", "/")
If you want to replace pair backslashes, you should double the effort:
scriptPath = scriptPath.replaceAll("\\\\\\\\", "/")
Those lines are successfully used in the Gradle/Groovy script I have intentionally launched just now once more - just to be sure.
What is even more funny, to show these necessary eight backslashes "\\\\\\\\" in the normal text here on StackOverflow, I have to use sixteen of them! Sorry, I won't show you these sixteen, for I would need 32! And it will never end...

If you're working with paths, you're better off using the java.io.File object. It will automatically convert the given path to the correct operating-system dependant path.
For example, (on Windows):
String path = "C:\\Test\\Test1\\Test2\\Test3\\";
// Prints C:\Test\Test1\Test2\Test3
System.out.println(new File(path).getAbsolutePath());
path = "/Test/Test1/Test2/Test3/";
// Prints C:\Test\Test1\Test2\Test3
System.out.println(new File(path).getAbsolutePath());

1) afile.replace(...) doesn't modify the string you're calling it on, it just returns a new string.
2) The input strings (String file ="C:\\Test\\Test1\\Test2\Test3\\";), from Java's perspective, only contain single backslashes. The first backslash is the escape character, then the second backslash tells it that you actually want a backslash.
so
afile.replace("\\\\", "/");
afile.replaceAll("\\\\", "/");
should be...
afile = afile.replace("\\", "/");
afile = afile.replaceAll("\\", "/");

In Groovy you can use regex in this way as well:
afile = afile.replaceAll(/(\\)/, "/")
println("replaced string: "+ afile)
Note that (as Sorrow said) replaceAll returns the result, doesn't modify the string. So you need to assign to a var before printing.

String Object is immutable so if you call a method on string object that modifies it. It will always return a new string object(modified). So you need to store the result return by replaceAll() method into a String object.

As found here, the best candidate might be the static Matcher method:
Matcher.quoteReplacement( ... )
According to my experiments this doubles single backslashes. Despite the method name... and despite the slightly cryptic Javadoc: "Slashes ('\') and dollar signs ('$') will be given no special meaning"