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Java - Remove only the first backslash

Small Java question regarding how to remove only the first backslash please.
I have a string which looks like this:
String s = "\\u6df1\\u5733";
Please note, there are two backslashes, and multiple occurrences.
Hence, when this is displayed, the visual result is:
\深\圳
I would like to just remove any extra backslashes, having a result like this:
深圳
So far, I have tried this:
String s = "\\u6df1\\u5733";
String ss = s.replaceAll("\\", "");
But it is still not working.
What is the correct solution please in order to get 深圳 from "\\u6df1\\u5733" please?
Thank you

Try this.
String s = "\\u6df1\\u5733";
Pattern UNICODE_ESCAPE = Pattern.compile("\\\\u[0-9a-f]+", Pattern.CASE_INSENSITIVE);
String ss = UNICODE_ESCAPE.matcher(s).results()
.map(x -> new String(Character.toChars(Integer.parseInt(x.group().substring(2), 16))))
.collect(Collectors.joining());
System.out.println(ss);
UNICODE_ESCAPE.matcher(s).results() returns the stream of MatcherResult.
x.group().substring(2) extracts hexadecimal part "xxxx" from "\\uxxxx".
Integer.parseInt(..., 16) converts it to an integer value that is a code point.
Caracter.toChars() converts it to an array of char.
new String(...) converts it to an String. And .collect(Collectors.joining()) concatenates the all of them.
output:
深圳

Going by this output:
\深\圳
you actually have two unicode characters each preceded by one backslash.
In a Java string literal, that would look like this:
String s = "\\\u6df1\\\u5733";
If you want to remove the backslashes (\\) and leave the unicode character codes (e.g. \u6df1), then you just need replace.
String ss = s.replace("\\", "");
replaceAll won't work for this, because it requires a regular expression as its first argument.

Add character into middle of String

I need your help to turn a String like 12345678 into 1234.56.78
[FOUR DIGITS].[TWO DIGITS].[TWO DIGITS]
My code:
String s1 = "12345678";
s1 = s1.replaceAll("(\\d{4})(\\d+)", "$1.$2").replaceAll("(\\d{2})(\\d+)", "$1.$2");
System.out.println(s1);
But the result is 12.34.56.78

If you are sure that you'll always have the input in the same format then you can simply use a StringBuilder and do something like this:
String input = "12345678";
String output = new StringBuilder().append(input.substring(0, 4))
.append(".").append(input.substring(4, 6)).append(".")
.append(input.substring(6)).toString();
System.out.println(output);
This code creates a new String by appending the dots to the sub-strings at the specified locations.
Output:
1234.56.78

Use a single replaceAll() method with updated regex otherwise the second replaceAll() call will replace including the first four digits.
System.out.println(s1.replaceAll("(\\d{4})(\\d{2})(\\d+)", "$1.$2.$3")

This puts dots after every pair of chars, except the first pair:
str = str.replaceAll("(^....)|(..)", "$1$2.");
This works for any length string, including odd lengths.
For example
"1234567890123" --> "1234.56.78.90.12.3"

java how to split string from end

I have a string like "test.test.test"...".test" and i need to access last "test" word in this string. Note that the number of "test" in the string is unlimited. if java had a method like php explode function, everything was right, but... . I think splitting from end of string, can solve my problem.
Is there any way to specify direction for split method?
I know one solution for this problem can be like this:
String parts[] = fileName.split(".");
//for all parts, while a parts contain "." character, split a part...
but i think this bad solution.

Try substring with lastIndexOf method of String:
String str = "almas.test.tst";
System.out.println(str.substring(str.lastIndexOf(".") + 1));
Output:
tst

I think you can use lastIndexOf(String str) method for this purpose.
String str = "test.test.test....test";
int pos = str.lastIndexOf("test");
String result = str.substring(pos);

Splitting string into substring in Java

I have one string and I want to split it into substring in Java, originally the string is like this
Node( <http://www.mooney.net/geo#wisconsin> )
Now I want to split it into substring by (#), and this is my code for doing it
String[] split = row.split("#");
String word = split[1].trim().substring(0, (split[1].length() -1));
Now this code is working but it gives me
"wisconsin>"
the last work what I want is just the work "wisconsin" without ">" this sign, if someone have an idea please help me, thanks in advance.

Java1.7 DOC for String class
Actually it gives you output as "wisconsin> " (include space)
Make subString() as
String word = split[1].trim().substring(0, (split[1].length()-3));
Then you will get output as
wisconsin
Tutorials Point String subString() method reference

Consider
String split[] = row.split("#|<|>");
which delivers a String array like this,
{"http://www.mooney.net/geo", "wisconsin"}
Get the last element, at index split.length()-1.

String string = "Enter parts here";
String[] parts = string.split("-");
String part1 = parts[0];
String part2 = parts[1];

you can just split like you did before once more (with > instead of #) and use the element [0] istead of [1]

You can just use replace like.
word.replace(char oldChar, char newChar)
Hope that helps

You can use Java String Class's subString() method.
Refer to this link.

the best way for character replacement in String in java

I want to check a string for each character I replace it with other characters or keep it in the string. and also because it's a long string the time to do this task is so important. what is the best way of these, or any better idea?
for all of them I append the result to an StringBuilder.
check all of the characters with a for and charAt commands.
use switch like the previous way.
use replaceAll twice.
and if one of the first to methods is better is there any way to check a character with a group of characters, like :
if (st.charAt(i)=='a'..'z') ....
Edit:
please tell the less consuming in time way and tell the reason.I know all of these ways you said!

If you want to replace a single character (or a single sequence), use replace(), as other answers have suggested.
If you want to replace several characters (e.g., 'a', 'b', and 'c') with a single substitute character or character sequence (e.g., "X"), you should use a regular expression replace:
String result = original.replaceAll("[abc]", "X");
If you want to replace several characters, each with a different replacement (e.g., 'a' with 'A', 'b' with 'B'), then looping through the string yourself and building the result in a StringBuilder will probably be the most efficient. This is because, as you point out in your question, you will be going through the string only once.
String sb = new StringBuilder();
String targets = "abc";
String replacements = "ABC";
for (int i = 0; i < result.length; ++i) {
char c = original.charAt(i);
int loc = targets.indexOf(c);
sb.append(loc >= 0 ? replacements.charAt(loc) : c);
}
String result = sb.toString();

Check the documentation and find some good methods:
char from = 'a';
char to = 'b';
str = str.replace(from, to);

String replaceSample = "This String replace Example shows
how to replace one char from String";
String newString = replaceSample.replace('r', 't');
Output: This Stting teplace Example shows how to teplace one chat ftom Stting
Also, you could use contains:
str1.toLowerCase().contains(str2.toLowerCase())
To check if the substring str2 exists in str1
Edit.
Just read that the String come from a file. You can use Regex for this. That would be the best method.
http://docs.oracle.com/javase/tutorial/essential/regex/literals.html

This is your comment:
I want to replace all of the uppercases to lower cases and replace all
of the characters except a-z with space.
You can do it like this:
str = str.toLowerCase().replaceAll("[^a-z]", " ");
Your requirement should be part of the question, not in comment #7 under a posted answer...

You should look into regex for Java. You can match an entire set of characters. Strings have several functions: replace, replaceAll, and match, which you may find useful here.
You can match the set of alphanumeric, for instance, using [a-zA-Z], which may be what you're looking for.