String replace a Backslash

问题

How can I do a string replace of a back slash.

Input Source String:

sSource = \"http://www.example.com\\/value\";

In the above String I want to replace \"\\/\" with a \"/\";

Expected ouput after replace:

sSource = \"http://www.example.com/value\";

I get the Source String from a third party, therefore I have control over the format of the String.

This is what I have tried

Trial 1:

sSource.replaceAll(\"\\\\\", \"/\");

Exception Unexpected internal error near index 1 \\

Trial 2:

 sSource.replaceAll(\"\\\\/\", \"/\");

No Exception, but does not do the required replace. Does not do anything.

Trial 3:

 sVideoURL.replace(\"\\\\\", \"/\"); 

No Exception, but does not do the required replace. Does not do anything.

回答1:

sSource = sSource.replace("\\/", "/");

• String is immutable - each method you invoke on it does not change its state. It returns a new instance holding the new state instead. So you have to assign the new value to a variable (it can be the same variable)
• replaceAll(..) uses regex. You don't need that.

回答2:

Try replaceAll("\\\\", "") or replaceAll("\\\\/", "/").

The problem here is that a backslash is (1) an escape-chararacter in Java-Strings, and (2) an Escape-Character in regular Expressions - each of this uses need doubling the character, in effect needing 4 \ in row.

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Edit: Of course, as Bozho said, you need to do something with the result (assign it to some variable) and not throw it away. And in this case the non-regex variant is better.

回答3:

Try

   sSource = sSource.replaceAll("\\\\", "");

Edit : Ok even in stackoverflow there is backslash escape... You need to have four backslashes in your replaceAll first String argument...

The reason of this is because backslash is considered as an escape character for special characters (like \n for instance).
Moreover replaceAll first arg is a regular expression that also use backslash as escape sequence.
So for the regular expression you need to pass 2 backslash. To pass those two backslashes by a java String to the replaceAll, you also need to escape both backslashes.
That drives you to have four backslashes for your expression! That's the beauty of regex in java ;)

回答4:

s.replaceAll ("\\\\", "");

You need to mask a backslash in your source, and for regex, you need to mask it again, so for every backslash you need two, which ends in 4.

But

s = "http://www.example.com\\/value";

needs two backslashes in source as well.

回答5:

This will replace backslashes with forward slashes in the string:

source = source.replace('\\','/');

回答6:

you have to do

sSource.replaceAll("\\\\/", "/");

because the backshlash should be escaped twice one for string in source one in regular expression

回答7:

 sSource = StringUtils.replace(sSource, "\\/", "/")

回答8:

To Replace backslash at particular location:

if ((stringValue.contains("\\"))&&(stringValue.indexOf("\\", location-1)==(location-1))) {
    stringValue=stringValue.substring(0,location-1);
}

来源：https://stackoverflow.com/questions/5596458/string-replace-a-backslash