Java Language Console I/O Aligning strings in console
Example
The method PrintWriter.format (called through System.out.format) can be used to print aligned strings in console. The method receives a String with the format information and a series of objects to format:
String rowsStrings[] = new String[] {"1",
"1234",
"1234567",
"123456789"};
String column1Format = "%-3s"; // min 3 characters, left aligned
String column2Format = "%-5.8s"; // min 5 and max 8 characters, left aligned
String column3Format = "%6.6s"; // fixed size 6 characters, right aligned
String formatInfo = column1Format + " " + column2Format + " " + column3Format;
for(int i = 0; i < rowsStrings.length; i++) {
System.out.format(formatInfo, rowsStrings[i], rowsStrings[i], rowsStrings[i]);
System.out.println();
}
Output:
1 1 1
1234 1234 1234
1234567 1234567 123456
123456789 12345678 123456
Using format strings with fixed size permits to print the strings in a table-like appearance with fixed size columns:
String rowsStrings[] = new String[] {"1",
"1234",
"1234567",
"123456789"};
String column1Format = "%-3.3s"; // fixed size 3 characters, left aligned
String column2Format = "%-8.8s"; // fixed size 8 characters, left aligned
String column3Format = "%6.6s"; // fixed size 6 characters, right aligned
String formatInfo = column1Format + " " + column2Format + " " + column3Format;
for(int i = 0; i < rowsStrings.length; i++) {
System.out.format(formatInfo, rowsStrings[i], rowsStrings[i], rowsStrings[i]);
System.out.println();
}
Output:
1 1 1
123 1234 1234
123 1234567 123456
123 12345678 123456
Format strings examples
%s: just a string with no formatting%5s: format the string with a minimum of 5 characters; if the string is shorter it will be padded to 5 characters and right aligned%-5s: format the string with a minimum of 5 characters; if the string is shorter it will be padded to 5 characters and left aligned%5.10s: format the string with a minimum of 5 characters and a maximum of 10 characters; if the string is shorter than 5 it will be padded to 5 characters and right aligned; if the string is longer than 10 it will be truncated to 10 characters and right aligned%-5.5s: format the string with a fixed size of 5 characters (minimum and maximum are equals); if the string is shorter than 5 it will be padded to 5 characters and left aligned; if the string is longer than 5 it will be truncated to 5 characters and left aligned
