Java by API/java.util/Formatter

Formatter: format("|%-10.2f|", ) ( left justify )

/*
|123.12    |
 */
import java.util.Formatter;
public class MainClass {
  public static void main(String args[]) {
    Formatter fmt = new Formatter();
    // left justify. 
    fmt.format("|%-10.2f|", 123.123); 
    System.out.println(fmt); 
  }
}

Formatter: format("|%10.2f|", ) (Right justify by default)

/*
|    123.12|
 */
import java.util.Formatter;
public class MainClass {
  public static void main(String args[]) {
    Formatter fmt = new Formatter();
    // Right justify by default 
    fmt.format("|%10.2f|", 123.123); 
    System.out.println(fmt); 
  }
}

Formatter: format("%.15s", String str) (Display at most 15 characters in a string)

/*
 Formatting with
 */
import java.util.Formatter;
public class MainClass {
  public static void main(String args[]) {
    Formatter fmt = new Formatter();
    // Display at most 15 characters in a string.
    fmt = new Formatter();
    fmt.format("%.15s", "Formatting with Java is now easy.");
    System.out.println(fmt);
  }
}

Formatter: format("%16.2e", Format to 2 decimal places in a 16 character field)

/*
        1.23e+02
 */
import java.util.Formatter;
public class MainClass {
  public static void main(String args[]) {
    Formatter fmt = new Formatter();
    // Format to 2 decimal places in a 16 character field. 
    fmt = new Formatter(); 
    fmt.format("%16.2e", 123.1234567); 
    System.out.println(fmt); 
  }
}

Formatter: format("%4d %4d %4d",

/*
  1    2    3
 */
import java.util.Formatter;
public class MainClass {
  public static void main(String args[]) {
    Formatter fmt = new Formatter();
    
    fmt.format("%4d %4d %4d", 1, 2, 3); 
    System.out.println(fmt); 
  }
}

Formatter: format("%.4f", Format 4 decimal places)

/*
123.1235
 */
import java.util.Formatter;
public class MainClass {
  public static void main(String args[]) {
    Formatter fmt = new Formatter();
    // Format 4 decimal places. 
    fmt.format("%.4f", 123.1234567); 
    System.out.println(fmt); 
  }
}

Formatter: format("% d", -the space format specifiers)

/*
-100
 100
-200
 200
 */
import java.util.Formatter;
public class MainClass {
  public static void main(String args[]) {
    Formatter fmt = new Formatter();
    fmt.format("% d", -100); 
    System.out.println(fmt); 
 
    fmt = new Formatter(); 
    fmt.format("% d", 100); 
    System.out.println(fmt); 
 
    fmt = new Formatter(); 
    fmt.format("% d", -200); 
    System.out.println(fmt); 
 
    fmt = new Formatter(); 
    fmt.format("% d", 200); 
    System.out.println(fmt); 
  }
}

Formatter: format("|%f|%n|%12f|%n|%012f|", (a field-width specifier)

/*
|10.123450|
|   10.123450|
|00010.123450|
 */
import java.util.Formatter;
public class MainClass {
  public static void main(String args[]) {
    Formatter fmt = new Formatter();
    fmt.format("|%f|%n|%12f|%n|%012f|", 10.12345, 10.12345, 10.12345);
    System.out.println(fmt);
  }
}

Formatter: format("%g", i)

/*
1000.00 
1000.00 100000 
1000.00 100000 1.00000e+07 
1000.00 100000 1.00000e+07 1.00000e+09 
 */
import java.util.Formatter;
public class MainClass {
  public static void main(String args[]) {
    Formatter fmt = new Formatter();
    for (double i = 1000; i < 1.0e+10; i *= 100) {
      fmt.format("%g ", i);
      System.out.println(fmt);
    }
  }
}

Formatter: format("%n %d%% ", 88) (the %n and %% format specifiers)

/*
Copying file
Transfer is 88% complete
 */
import java.util.Formatter;
public class MainClass {
  public static void main(String args[]) {
    Formatter fmt = new Formatter();
    fmt.format("Copying file%nTransfer is %d%% complete", 88);
    System.out.println(fmt);
  }
}

Formatter: format(String format, Object... args)

/*
1000.00 
1000.00 100000 
1000.00 100000 1.00000e+07 
1000.00 100000 1.00000e+07 1.00000e+09 
 */
import java.util.Formatter;
public class MainClass {
  public static void main(String args[]) {
    Formatter fmt = new Formatter();
    for (double i = 1000; i < 1.0e+10; i *= 100) {
      fmt.format("%g ", i);
      System.out.println(fmt);
    }
  }
}

Formatter: format("%tB %tb %tm", cal, cal, cal) (Display month by name and number)

/*
 June Jun 06
 */
import java.util.Calendar;
import java.util.Formatter;
public class MainClass {
  public static void main(String args[]) {
    Formatter fmt = new Formatter();
    Calendar cal = Calendar.getInstance();
    // Display month by name and number. 
    fmt = new Formatter(); 
    fmt.format("%tB %tb %tm", cal, cal, cal); 
    System.out.println(fmt); 
  }
}

Formatter: format("%tc", cal) (Display complete time and date information)

/*
Wed Jun 07 15:18:00 PDT 2006
 */
import java.util.Calendar;
import java.util.Formatter;
public class MainClass {
  public static void main(String args[]) {
    Formatter fmt = new Formatter();
    Calendar cal = Calendar.getInstance();
    fmt = new Formatter();
    fmt.format("%tc", cal);
    System.out.println(fmt);
  }
}

Formatter: format("%te of % < tB, % < tY", cal)

/*
Today is day 7 of June, 2006
 */
import java.util.Calendar;
import java.util.Formatter;
public class MainClass {
  public static void main(String args[]) {
    Formatter fmt = new Formatter();
    Calendar cal = Calendar.getInstance();
    fmt.format("Today is day %te of %<tB, %<tY", cal);
    System.out.println(fmt);
  }
}

Formatter: format("%tl:%tM", cal, cal) (Display just hour and minute)

/*
 4:44
 */
import java.util.Calendar;
import java.util.Formatter;
public class MainClass {
  public static void main(String args[]) {
    Formatter fmt = new Formatter();
    Calendar cal = Calendar.getInstance();
    // Display just hour and minute. 
    fmt = new Formatter(); 
    fmt.format("%tl:%tM", cal, cal); 
    System.out.println(fmt); 
  }
}

Formatter: format("%tr", cal) (Display standard 12-hour time format)

/*
 1000.00 
 1000.00 100000 
 1000.00 100000 1.00000e+07 
 1000.00 100000 1.00000e+07 1.00000e+09 
 */
import java.util.Calendar;
import java.util.Formatter;
public class MainClass {
  public static void main(String args[]) {
    Formatter fmt = new Formatter();
    Calendar cal = Calendar.getInstance();
    fmt.format("%tr", cal);
    System.out.println(fmt);
  }
}

new Formatter(Appendable a)

/*
   2)+1234.12
 */
import java.util.Formatter;
public class MainClass {
  public static void main(String[] args) throws Exception {
    StringBuilder buf = new StringBuilder(); // Buffer to hold output
    Formatter formatter = new Formatter(buf); // Formatter to format data into
                                              // buf
    formatter.format("%4d)%+7.2f", 2, 1234.1234);
    System.out.println(buf);
  }
}