How to read % Character in Java

Question

i have to write a little parsing application, which is rewriting a postscriptfile with some additional infos.

To reach that goal, i am just using a BufferedReader with a FileReader and a FileWriter. But i am reaching into a problem with an escape character (the % sign).

Java is ignoring this character, the line "%!PS-Adobe-3.0" from the input file will be "!PS-Adobe-3.0" in the String and further the same in the output file.

Do you fellaz have any ideas, how i can do that ... except from reading bytewise :D

Best regards

edit: Here is the code fragment ... the base file is in encoded in UTF8 :

BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(args[0]), "UTF-8")); String line = br.readLine();

Before i testet it with the following: BufferedReader br = new BufferedReader(new FileReader(args[0]));

It fails at the same problem -> "%!PS-Adobe-3.0" from the input file became "!PS-Adobe-3.0" in the variable "line"

Show the code where you're trying to read that. % is not special to any of the classes you've listed. — T.J. Crowder
– T.J. Crowder, Commented May 26, 2014 at 11:49
There's nothing about your now-quoted code that would prevent your reading the % correctly. Either the character isn't there and you just think it is (perhaps whatever you're using to look at it uses % to indicate something?), or you're doing something else, elsewhere, that strips it out or treats it specially. — T.J. Crowder
– T.J. Crowder, Commented May 26, 2014 at 12:00
Here are the first lines of the .ps File i try to read into java: %!PS-Adobe-3.0 %%Creator: CompuSet Version 9.4.0 %%CreationDate: 5/15/2014 11:11:16 %%BoundingBox: 0 0 595 842 %%Pages: (atend) %%DocumentNeededResources: (atend) %%DocumentSuppliedResources: (atend) The first % sign at the lines which are begining with "%%" will also be ignored. — user2865676
– user2865676, Commented May 26, 2014 at 12:01
And no ... i am creating the BufferedReader and a the next line i am using br.readLine() ... how should i "manipulate" it otherwise. Thanks for your great answer — user2865676
– user2865676, Commented May 26, 2014 at 12:08
See above: If those characters are really there, they will be read by the above. What makes you think they aren't being? — T.J. Crowder
– T.J. Crowder, Commented May 26, 2014 at 12:29

T.J. Crowder · Accepted Answer · 2014-05-26 12:34:50Z

The % will be read from the file using the code you've quoted. As I've said in comments on the question, if the characters are really there (and I expect they are), the issue is not in that code, but in the code later.

From this comment:

%!PS-Adobe-3.0 %%Creator: CompuSet Version 9.4.0 %%CreationDate: 5/15/2014 11:11:16 %%BoundingBox: 0 0 595 842 %%Pages: (atend) %%DocumentNeededResources: (atend) %%DocumentSuppliedResources: (atend) The first % sign at the lines which are begining with "%%" will also be ignored.

...I'm guessing you're outputting what you're reading using System.out.printf, but incorrectly like this:

System.out.printf(line); // <=== Wrong

The first string you pass into printf is a formatting string, and it can placeholders that start with %. The %% is a special "placeholder" that outputs %.

So you're not really seeing the contents of line. Try using print or println instead:

System.out.println(line);

...or use printf correctly:

System.out.printf("%s\n", line);

%s outputs a string unchanged.

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