How to replace '\' by '\\' in java string?

Question

Hi I want to replace a backslash character \ by double backslash character \\ from a string in Java but the replace() method does not seem to work. It gives an arguments mismatch error. I think it does not work with special characters. Any get around to this?

Here is my code snippet:

String fileSeparator = System.getProperty("file.separator");
        JFileChooser chooser = new JFileChooser();
        chooser.setCurrentDirectory(new java.io.File("."));
        chooser.setDialogTitle("Locate Java Documentation Folder");
        chooser.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);
        chooser.setAcceptAllFileFilterUsed(false);

        if (chooser.showOpenDialog(this) == JFileChooser.APPROVE_OPTION) {
            JTextField jtfFileLocation=new JTextField();
            jtfFileLocation.setText(chooser.getSelectedFile().getPath()+fileSeparator);
            String filePath=jtfFileLocation.getText();
            filePath.replaceAll("\\", "\\\\");
            System.out.println(filePath);
        } else {

        }

Did you really search ? http://stackoverflow.com/questions/7535317/how-to-replace-with-in-java — Alexis C., May 26 '13 at 14:07

score 7 · Accepted Answer · answered May 26 '13 at 14:07

7

You're most probably not escaping your backslashes correctly:

String newString = oldString.replace("\\", "\\\\");

One literal backslash has to be encoded by two backslash characters. Be glad that it's not a regex you're dealing with:

String newString = oldString.replaceAll("\\\\", "\\\\\\\\");

answered May 26 '13 at 14:07

Tim Pietzcker

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Only the first parameter for the `replaceAll` method is a regex. The replacement would still be `"\\\\"`. – Lone nebula May 26 '13 at 14:13
2

@Lonenebula: No, the backslash is still a special character in a regex replacement string and needs to be escaped. Try it. – Tim Pietzcker May 26 '13 at 14:16
You are completely right. – Lone nebula May 26 '13 at 14:18
Thank you very much for your answer @Tim Pietzcker. Actually what I am trying to do is: I take a directry path from JFileChooser and hold its path in a string variable, and when I use that path in stream variable it gives me an error. When I hardcode the file path by replacing a single slash by double slash then my program works. Your replace method is still not replacing the single slash by double slash. Thanks much for your help – user1515601 May 26 '13 at 14:18
@user1515601: Can you post the code that's not working for you? – Tim Pietzcker May 26 '13 at 14:22
Can't post the code of whole application but can post a snippet where I take in the file path dynamically. Please see the edit of the question. – user1515601 May 26 '13 at 14:30
Done with that. Thanks for your answers. I needed to declare a new string variable as String variables are immutable. – user1515601 May 26 '13 at 14:42

score 0 · Answer 2 · answered May 26 '13 at 14:08

0

Try String newString = originalString.replace("\\", "\\\\");

answered May 26 '13 at 14:08

Aniket Thakur

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How to replace '\' by '\\' in java string?

2 Answers2