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Regex to split a string based on \r characters not a carriage return or a new line

i want a Regex expression to split a string based on \r characters not a carriage return or a new line.
Below is the sample string i have.
MSH|^~\&|1100|CB|CERASP|TESTSB8F|202008041554||ORU|1361|P|2.2\rPID|1|833944|21796920320|8276975
i want this to be split into
MSH|^~\&|1100|CB|CERASP|TESTSB8F|202008041554||ORU|1361|P|2.2
PID|1|833944|21796920320|8276975
currently i have something like this
StringUtils.split(testStr, "\\r");
but it is splitting into
MSH|^~
&|1100|CB|CERASP|TESTSB8F|202008041554||ORU|1361|P|2.2
PID|1|833944|21796920320|8276975

You can just use String#split:
final String str = "MSH|^~\\&|1100|CB|CERASP|TESTSB8F|202008041554||ORU|1361|P|2.2\\rPID|1|833944|21796920320|8276975";
final String[] substrs = str.split("\\\\r");
System.out.println(Arrays.toString(substrs));
// Outputs [MSH|^~\&|1100|CB|CERASP|TESTSB8F|202008041554||ORU|1361|P|2.2, PID|1|833944|21796920320|8276975]

You can use
import java.utl.regex.*;
//...
String[] results = text.split(Pattern.quote("\\r"));
The Pattern.quote allows using any plain text inside String.split that accepts a valid regular expression. Here, \ is a special char, and needs to be escaped for both Java string interpretation engine and the regex engine.

The method being called matches any one of the contents in the delimiter string as a delimiter, not the entire sequence. Here is the code from SeparatorUtils that executes the delimiter (str is the input string being split) check:
if (separatorChars.indexOf(str.charAt(i)) >= 0) {
As #enzo mentioned, java.lang.String.split() will do the job - just make sure to quote the separator. Pattern.quote() can help.

How to replace \ with . in java String

I want to replace \ with . in String java.
Example src\main\java\com\myapp\AppJobExecutionListener
Here I want to get like src.main.java.com.myapp.AppJobExecutionListener
I tried str.replaceAll("\\","[.]") and str.replaceAll("\\","[.]") but it is not working.
I am still getting original string src\main\java\com\myapp\AppJobExecutionListener

String is immutable in Java, so whatever methods you invoke on the String object are not reflected on it unless you reassign it.
String s = "ABC";
s.replaceAll("B","D");
System.out.println(s); //still prints "ABC"
s = s.replaceAll("B","D");
System.out.println(s); //prints "ADC"

Currently you're using replaceAll, which takes regular expression patterns. That makes life much more complicated than it needs to be. Unless you're trying to use regular expressions, just use String.replace instead.
In fact, as you're only replacing one character with another, you can just use character literals:
String replaced = original.replace('\\', '.');
The \ is doubled as it's the escape character in Java character literals - but as the above doesn't use regular expressions, the period has no special meaning.

Assign it back to string str variable, .String#replaceAll doesn't changes the string itself, it returns a new String.
str = str.replaceAll("\\\\",".")

Can you try this:
String original = "Some text with \\ and rest of the text";
String replaced = original.replace("\\",".");
System.out.println(replaced);

'\' character is doubled in a string like '\\'. So '\\' character should be used to replace it with '.' character and also using replace instead of replaceAll would be enough to make it. Here is a sample;
public static void main(String[] args) {
String myString = "src\\main\\java\\com\\vxl\\appanalytix\\AppJobExecutionListener";
System.out.println("Before Replaced: " + myString);
myString = myString.replace("\\", ".");
System.out.println("After Replaced: " + myString);
}
This will give you:
Before Replaced: src\main\java\com\vxl\appanalytix\AppJobExecutionListener
After Replaced: src.main.java.com.vxl.appanalytix.AppJobExecutionListener

With String replaceAll(String regex, String replacement):
str = str.replaceAll("\\\\", ".");
With String replace(char oldChar, char newChar):
str = str.replace('\\', '.');
With String replace(CharSequence target, CharSequence replacement)
str = str.replace("\\", ".");

String replaced = original.replace('\', '.');
try this its works well

Use replace instead of replaceall
String my_str="src\\main\\java\\com\\vxl\\appanalytix\\AppJobExecutionListener";
String my_new_str = my_str.replace("\\", ".");
System.out.println(my_new_str);
DEMO AT IDEONE.COM

replaceAll takes a regex as the first parameter.
To replace the \ you need to double escape. You need an additional \ to escape the first . And as it is a regex input you need to escape those again. As other answers have said string is immutable so you will need to assign the result
String newStr = str.replaceAll("\\\\", ".");
The second parameter is not regex so you can just put . in there but note you need four slashes to replace one backslash if using replaceAll

i tried this:
String s="src\\main\\java\\com\\vxl\\appanalytix\\AppJobExecutionListener";
s = s.replace("\\", ".");
System.out.println("s: "+ s);
output: src.main.java.com.vxl.appanalytix.AppJobExecutionListener

Just change the line to
str = str.replaceAll("\\",".");
Edit : I didnt try it, because the problem here is not whether its a correct regex,but the problem here is that he is not assigning the str to new str value. Anyways regex corrected now.

String.split(".") is not splitting my long String

I'm doing the following:
String test = "this is a. example";
String[] test2 = test.split(".");
the problem: test2 has no items. But there are many . in the test String.
Any idea what the problem is?

Note that public String[] split(String regex) takes a regex.
You need to escape the special char ..
Use String[] test2 = test.split("\\.");
Now you're telling Java:
"Don't take . as the special char ., take it as the regular char .".
Note that escaping a regex is done by \, but in Java, \ is written as \\.
As suggested in the comments by #OldCurmudgeon (+1), you can use public static String quote(String s) that "Returns a literal pattern String for the specified String":
String[] test2 = test.split(Pattern.quote("."));

The dot . is special regex character. It means match any. You need to escape the character, which in Java is done with \\.
Once it is escaped, it won't be treated as special and will be matched just like any other character.
So String[] test2 = test.split("\\."); should do the trick nicely!

replace all + with -

I am trying to replace a + character into a hyphen I have in my string.
String str = "word+word";
str.replaceAll('+ ', '-');
I tried using replace but it throwing an exception.Is there any other method to do this.

Use
str = str.replaceAll("\\+", "-");
A few errors in your code :
replaceAll takes strings, not chars
the + char must be escaped as the first argument is a regular expression (and \ itself must be escaped in java string literals)
you must take the return of the function : as String is immutable the function doesn't change it but returns another string

Just use replace:
str = str.replace('+', '-');
This one doesn't work on regex but take characters as they are.
Also as you see you have to reassing value again to your str variable because String in Java are immutable. In this case method replace doesn't change current String (str) but create new one with replaced + to '-'.

`replaceAll´ is for regular expressions and strings are immutable. Use:
str = str.replace("+", "-");
instead...

The replaceAll function takes a regular expression as its first argument. It so happens that + is a special character in regular expression language. Try replacing + with \\+. This will escape the plus sign, thus making the code to treat it like a normal character.
Also, the replaceAll method yields a string, so that will not work. Try doing:
String str = "word+word";
str = str.replaceAll("\\+ ", "-");

Use "" as opposed to '' in replaceAll.
String java.lang.String.replaceAll(String regex, String replacement)

If you are not sure about the escape sequence you need to use,
You could simply do this.
str = str.replaceAll(Pattern.quote("+"), "-");
This will automatically escape the regex predefined tokens to match in a literal way

How to replace special characters in a string?

I have a string with lots of special characters. I want to remove all those, but keep alphabetical characters.
How can I do this?

That depends on what you mean. If you just want to get rid of them, do this:
(Update: Apparently you want to keep digits as well, use the second lines in that case)
String alphaOnly = input.replaceAll("[^a-zA-Z]+","");
String alphaAndDigits = input.replaceAll("[^a-zA-Z0-9]+","");
or the equivalent:
String alphaOnly = input.replaceAll("[^\\p{Alpha}]+","");
String alphaAndDigits = input.replaceAll("[^\\p{Alpha}\\p{Digit}]+","");
(All of these can be significantly improved by precompiling the regex pattern and storing it in a constant)
Or, with Guava:
private static final CharMatcher ALNUM =
CharMatcher.inRange('a', 'z').or(CharMatcher.inRange('A', 'Z'))
.or(CharMatcher.inRange('0', '9')).precomputed();
// ...
String alphaAndDigits = ALNUM.retainFrom(input);
But if you want to turn accented characters into something sensible that's still ascii, look at these questions:
Converting Java String to ASCII
Java change áéőűú to aeouu
ń ǹ ň ñ ṅ ņ ṇ ṋ ṉ ̈ ɲ ƞ ᶇ ɳ ȵ --> n or Remove diacritical marks from unicode chars

I am using this.
s = s.replaceAll("\\W", "");
It replace all special characters from string.
Here
\w : A word character, short for [a-zA-Z_0-9]
\W : A non-word character

You can use the following method to keep alphanumeric characters.
replaceAll("[^a-zA-Z0-9]", "");
And if you want to keep only alphabetical characters use this
replaceAll("[^a-zA-Z]", "");

Replace any special characters by
replaceAll("\\your special character","new character");
ex:to replace all the occurrence of * with white space
replaceAll("\\*","");
*this statement can only replace one type of special character at a time

Following the example of the Andrzej Doyle's answer, I think the better solution is to use org.apache.commons.lang3.StringUtils.stripAccents():
package bla.bla.utility;
import org.apache.commons.lang3.StringUtils;
public class UriUtility {
public static String normalizeUri(String s) {
String r = StringUtils.stripAccents(s);
r = r.replace(" ", "_");
r = r.replaceAll("[^\\.A-Za-z0-9_]", "");
return r;
}
}

string Output = Regex.Replace(Input, #"([ a-zA-Z0-9&, _]|^\s)", "");
Here all the special characters except space, comma, and ampersand are replaced. You can also omit space, comma and ampersand by the following regular expression.
string Output = Regex.Replace(Input, #"([ a-zA-Z0-9_]|^\s)", "");
Where Input is the string which we need to replace the characters.

Here is a function I used to remove all possible special characters from the string
let name = name.replace(/[&\/\\#,+()$~%!.„'":*‚^_¤?<>|#ª{«»§}©®™ ]/g, '').toLowerCase();

You can use basic regular expressions on strings to find all special characters or use pattern and matcher classes to search/modify/delete user defined strings. This link has some simple and easy to understand examples for regular expressions: http://www.vogella.de/articles/JavaRegularExpressions/article.html

You can get unicode for that junk character from charactermap tool in window pc and add \u e.g. \u00a9 for copyright symbol.
Now you can use that string with that particular junk caharacter, don't remove any junk character but replace with proper unicode.

For spaces use "[^a-z A-Z 0-9]" this pattern