How do you escape colon (:) in Properties file?

Question

I am using a properties file to store my application's configuration values. In one of the instances, I have to store a value as xxx:yyy:zzz. When I do that, the colon is escaped with a back slash\ resulting in the value showing as xxx\:yyy\:zzz in the properties file.

I am aware that the colon : is a standard delimiter of the Properties Java class. However I still need to save the value without the back slash \.

Any suggestions on how to handle this?

I fear you can't. Otherwise, how could the property files be read back without confusing "your" colons, and colons use to delimit key values? — ewernli, May 22 '12 at 09:20
Make a StringWriter, write your properties file into it, go through the buffer line-by-line looking for `"\:"`, and replacing it by a single `":"`. This is not pretty, but then again what you are trying to do is also not very pretty. — Sergey Kalinichenko, May 22 '12 at 09:29
@BhavikAmbani 'Use regular expressions' for that *how?* Where exactly do you get a chance to specify a regular expression when saving a properties file, and what exactly would the RE look like? — user207421, May 22 '12 at 10:06

score 21 · Accepted Answer · edited Apr 07 '14 at 15:52

Put the properties into the Properties object and save it using a store(...) method. The method will perform any escaping required. The Java documentation says:

"... For the key, all space characters are written with a preceding \ character. For the element, leading space characters, but not embedded or trailing space characters, are written with a preceding \ character. The key and element characters #, !, =, and : are written with a preceding backslash to ensure that they are properly loaded."

You only need to manually escape characters if you are creating / writing the file by hand.

Conversely, if you want the file to contain unescaped colon characters, you are out of luck. Such a file is malformed and probably won't load properly using the Properties.load(...) methods. If you go down this route, you'll need to implement your own custom load and/or store methods.

score 8 · Answer 2 · edited Dec 14 '16 at 18:41

I came across the same issue. Forward slashes / also get escaped by the store() method in Properties.

I solved this issue by creating my own CustomProperties class (extending java.util.Properties) and commenting out the call to saveConvert() in the customStore0() method.

Here is my CustomProperties class:

import java.io.BufferedWriter;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.util.Date;
import java.util.Enumeration;
import java.util.Properties;

public class CustomProperties extends Properties {
  private static final long serialVersionUID = 1L;
  @Override
  public void store(OutputStream out, String comments) throws IOException {
      customStore0(new BufferedWriter(new OutputStreamWriter(out, "8859_1")),
                   comments, true);
  }
  //Override to stop '/' or ':' chars from being replaced by not called 
  //saveConvert(key, true, escUnicode)
  private void customStore0(BufferedWriter bw, String comments, boolean escUnicode)
          throws IOException {
      bw.write("#" + new Date().toString());
      bw.newLine();
      synchronized (this) {
          for (Enumeration e = keys(); e.hasMoreElements();) {
              String key = (String) e.nextElement();
              String val = (String) get(key);
              // Commented out to stop '/' or ':' chars being replaced
              //key = saveConvert(key, true, escUnicode);
              //val = saveConvert(val, false, escUnicode);
              bw.write(key + "=" + val);
              bw.newLine();
          }
      }
      bw.flush();
  }
}

Hi, my problem here is that when saving a property, Java is interpreting the property value and if it finds for example this: '\n' it does a line break and saves a new property so the result is 2 property instead of one, any idea to fix it? — Despotars, Feb 17 '22 at 14:12

score 3 · Answer 3 · edited Dec 14 '16 at 18:51

We hit this question a couple of days ago. We were manipulating existing properties files with URLs as values.

It's risky but if your property values are less than 40 characters then you can use the "list" method instead of "store":

http://docs.oracle.com/javase/6/docs/api/java/util/Properties.html#list(java.io.PrintWriter)

We had a quick look at the JDK code and hacked out a custom implementation of store that works for our purposes:

public void store(Properties props, String propertyFilePath) throws FileNotFoundException {
    PrintWriter pw = new PrintWriter(propertyFilePath); 
    for (Enumeration e = props.propertyNames(); e.hasMoreElements();) {
        String key = (String) e.nextElement();
        pw.println(key + "=" + props.getProperty(key));
    }
    pw.close();
}

score 1 · Answer 4 · answered May 22 '12 at 09:18

1

If you use the xml variant of the properties file (using loadFromXML and storeToXML) this shouldn't be a problem.

answered May 22 '12 at 09:18

trutheality

23,114
6
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I like this approach too, but XML format is bit harder to read for noobs ("customers etc.")... I think there should be way how to escape :, or either use some utils to choose key value delimiter, as now : is taken as delimiter too... – To Kra Apr 17 '15 at 11:37

score 1 · Answer 5 · answered Jan 08 '21 at 08:56

For people like me that get here for this when using Spring Boot configuration properties files: You need to enclose in [..]:

E.g.:

my.test\:key=value

is not enough, you need this in your application.properties for example:

my.[test\:key]=value

See also SpringBoot2 ConfigurationProperties removes colon from yaml keys

score 0 · Answer 6 · edited Jun 15 '21 at 23:08

Its simple, just use Apostrophe ' ' over there E.g.:

Instead of this(case 1)

File file= new File("f:\\properties\\gog\\esave\\apple");
prop.setProperty("basedir",file.toString());

Use this(case 2)

File file= new File("f':'\\properties\\gog\\esave\\apple");
prop.setProperty("basedir",file.toString());

Output will be

Case 1: basedir = f\:\\properties\\gog\\esave\\apple

Case 2: basedir = f:\\properties\\gog\\esave\\apple

I hope this will help you

jspek · Answer 7 · 2019-12-12T17:49:57.960

0

Try using unicode.

The unicode for a colon is\u003A

Additionally the unicode for a space is: \u0020

For a list of basic Latin characters see: https://en.wikipedia.org/wiki/Basic_Latin_(Unicode_block)

For example:

ProperName\u003A\NameContinues=Some property value

Will expect a property with a key:

ProperName:NameContinues

And will have a value of:

Some property value

edited Dec 12 '19 at 17:49

answered Dec 06 '19 at 17:49

jspek

438
3
10

score 0 · Answer 8 · edited Jul 16 '20 at 18:11

0

For me it worked by using \ before special character,

e.g,

Before: VCS\u003aIC\u0020Server\u003a=Migration
After: VCS\:IC\ Server\:=Migration

: is escaped with \: and (space) with \ (\ followed by <Space>).

For more info : https://en.wikipedia.org/wiki/.properties

edited Jul 16 '20 at 18:11

omajid

14,165
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answered Jul 03 '20 at 09:16

Arun Chib

1
1

How do you escape colon (:) in Properties file?

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