Using SymmetricDS to connect to a firebird database [duplicate] - jdbc

Question

I am using Java Properties to read a properties file. Everything is working fine, but Properties silently drops the backslashes.
(i.e.)
original: c:\sdjf\slkdfj.jpg
after: c:sdjfslkdfj.jpg
How do I make Properties not do this?
I am using the code prop.getProperty(key)
I am getting the properties from a file, and I want to avoid adding double backslashes

Answer 1

It is Properties.load() that's causing the problem that you are seeing as backslash is used for a special purpose.
The logical line holding all the data
for a key-element pair may be spread
out across several adjacent natural
lines by escaping the line terminator
sequence with a backslash character,
\.
If you are unable to use CoolBeans's suggestion then what you can do is read the property file beforehand to a string and replace backslash with double-backslash and then feed it to Properties.load()
String propertyFileContents = readPropertyFileContents();
Properties properties = new Properties();
properties.load(new StringReader(propertyFileContents.replace("\\", "\\\\")));

Answer 2

Use double backslashes c:\\sdjf\\slkdfj.jpg
Properties props = new Properties();
props.setProperty("test", "C:\\dev\\sdk\\test.dat");
System.out.println(props.getProperty("test")); // prints C:\dev\sdk\test.dat
UPDATE CREDIT to #ewh below. Apparently, Windows recognises front slashes. So, I guess you can have your users write it with front slashes instead and if you need backslashes afterwards you can do a replace. I tested this snippet below and it works fine.
Properties props = new Properties();
props.setProperty("test", "C:/dev/sdk/test.dat");
System.out.println(props.getProperty("test")); // prints C:/dev/sdk/test.dat

Answer 3

Use forward slashes. There is never a need in Java to use a backslash in a filename.

Answer 4

In case you really need a backslash in a properties file that will be loaded (like for a property that is not a file path) put \u005c for each backslash character.
The backslash is treated specially in properties files as indicated in the document provided by #unhillbilly.
#EJP: Backslash is definitely needed if, for example, you wanted to store an NTLM login id in a properties file, where the format is DOMAIN\USERNAME with a backslash. This type of property is not a filename so forward slashes will not work.
Edit: #Max Nanasy: From the document (java.util.Properties load javadoc) mentioned above (emphasis mine)
The method does not treat a backslash character, '\', before a non-valid escape character as an error; the backslash is silently dropped. For example, in a Java string the sequence "\z" would cause a compile time error. In contrast, this method silently drops the backslash. Therefore, this method treats the two character sequence "\b" as equivalent to the single character 'b'
For me, I always had trouble with backslashes in the properties file (even with double backslash '\\') unless I specified the unicode.

Answer 5

Replace \ with \\ as below:
c:\sdjf\slkdfj.jpg
to
c:\\sdjf\\slkdfj.jpg

Answer 6

In addition to Bala R's answer I have the following solution to even keep the newline-semantic of backslashes at the end of a line.
Here is my code:
private static Reader preparePropertyFile(File file) throws IOException {
BufferedReader reader = new BufferedReader(new FileReader(file));
StringBuilder result = new StringBuilder();
String line;
boolean endingBackslash = false;
while ((line = reader.readLine()) != null) {
line = line.trim();
if (endingBackslash) {
// if the line is empty, is a comment or holds a new property
// definition the backslash found at the end of the previous
// line is not for a multiline property value.
if (line.isEmpty()
|| line.startsWith("#")
|| line.matches("^\\w+(\\.\\w+)*=")) {
result.append("\\\\");
}
}
// if a backslash is found at the end of the line remove it
// and decide what to do depending on the next line.
if (line.endsWith("\\")) {
endingBackslash = true;
line = line.substring(0, line.length() - 1);
} else {
endingBackslash = false;
}
result.append(line.replace("\\", "\\\\"));
}
if (endingBackslash) {
result.append("\\\\");
}
return new StringReader(result.toString());
}
private static Properties getProperties(File file) throws IOException {
Properties result = new Properties();
result.load(preparePropertyFile(file));
return result;
}

Answer 7

The following code will help :
BufferedReader metadataReader = new BufferedReader(new InputStreamReader(new FileInputStream("migrateSchemaGenProps.properties")));
Properties props = new Properties();
props.load(new StringReader(IOUtils.getStringFromReader(metadataReader).replace("\\", "/")));

Answer 8

It is not realy a good thing to use backslashes in a property-file, as they are the escape character.
Nevertheless: a Windows user will trend to use them in any path... Therefore, in a single line thanks apache common IO:
params.load(new StringReader(IOUtils.toString(paramFile.toURI(), null).replaceAll("\\\\", "/")));

Answer 9

you triple use the backslash to get one:
for example:
key=value1\\value2
in the properties file will turn to
key=value1\value2
in the java Properties object