Java Format Justifying Output

In this chapter you will learn:

How to justify Output
Syntax for justify
Example - left-justifies a floating-point number with two decimal places
Example - Use Formatter to left-justify strings within a table
Example - Use Formatter to vertically align numeric values
How to right and left align strings

Description

By default, all output is right-justified. You can force output to be left-justified by placing a minus sign directly after the %.

Syntax

fmt.format("|%#d|", 123.123);

fmt.format("|%#.#d|", 123.123);

Example

For instance, %-10.2f left-justifies a floating-point number with two decimal places in a 10-character field.


import java.util.Formatter;
/*from w  ww.j a  v  a  2 s  .  c  o m*/
public class Main {
  public static void main(String args[]) {
    Formatter fmt = new Formatter();
    // Right justify by default
    fmt.format("|%10.2f|", 123.123);
    System.out.println(fmt);
    // Now, left justify.
    fmt = new Formatter();
    fmt.format("|%-10.2f|", 123.123);
    System.out.println(fmt);
  }
}

The output:

Example 2

Use Formatter to left-justify strings within a table


import java.util.Formatter;
//w w w  .  ja v a 2s . c om
public class Main {
  public static void main(String args[]) {
    Formatter fmt = new Formatter();

    fmt.format("%-12s %12s\n\n", "Source", "Loss");
    fmt.format("%-12s %,12d\n", "Retail", 1232675);

    System.out.println(fmt);
  }
}

The code above generates the following result.

Example 3

Use Formatter to vertically align numeric values


import java.util.Formatter;
//w ww.  j  a va  2 s  . co m
public class Main {
  public static void main(String[] argv) throws Exception {
    double data[] = { 12.3, 45.6, -7.89, -1.0, 1.01 };
    Formatter fmt = new Formatter();

    fmt.format("%12s %12s\n", "Value", "Cube Root");

    for (double v : data) {
      fmt.format("%12.4f %12.4f\n", v, Math.cbrt(v));
    }
    System.out.println(fmt);
  }
}

The code above generates the following result.


       Value    Cube Root//from  ww w  .j a  va  2 s. c  o  m
     12.3000       2.3084
     45.6000       3.5726
     -7.8900      -1.9908
     -1.0000      -1.0000
      1.0100       1.0033

Example 4


public class Main {
  public static void main(String args[]) {
    String format = "|%1$-10s|%2$10s|%3$-20s|\n";
    System.out.format(format, "A", "AA", "AAA");
    System.out.format(format, "B", "", "BBBBB");
    System.out.format(format, "C", "CCCCC", "CCCCCCCC");
//www . ja va  2 s.c  o m
    String ex[] = { "E", "java2s.com", "E" };

    System.out.format(String.format(format, (Object[]) ex));
  }
}

The code above generates the following result.

Next chapter...

What you will learn in the next chapter:

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      Java Data Format

Java Formatter Class
Java Format Specifier
Java Format Specifier Uppercase
Java Format Precision
Java Format Flags

Java Format Justifying Output

Java Format Negative and Positive
Java Format Line up Space
Java Format Parentheses
Java Format Zero Padding
Java Format Comma
Java Format Alternate Conversion
Java Format Argument Index
Java Format date time
Java Format Date