How to add a UTF-8 BOM in Java?
BufferedWriter out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(...), StandardCharsets.UTF_8));
out.write('\ufeff');
out.write(...);
This correctly writes out 0xEF 0xBB 0xBF to the file, which is the UTF-8 representation of the BOM.
Just in case people are using PrintStream
s, you need to do it a little differently. While a Writer
will do some magic to convert a single byte into 3 bytes, a PrintStream
requires all 3 bytes of the UTF-8 BOM individually:
// Print utf-8 BOM
PrintStream out = System.out;
out.write('\ufeef'); // emits 0xef
out.write('\ufebb'); // emits 0xbb
out.write('\ufebf'); // emits 0xbf
Alternatively, you can use the hex values for those directly:
PrintStream out = System.out;
out.write(0xef); // emits 0xef
out.write(0xbb); // emits 0xbb
out.write(0xbf); // emits 0xbf
To write a BOM in UTF-8 you need PrintStream.print()
, not PrintStream.write()
.
Also if you want to have BOM in your csv
file, I guess you need to print a BOM after putNextEntry()
.