Use printf() to create a time stamp.

 

import java.io.FileWriter;
import java.io.PrintWriter;
import java.util.Calendar;

public class Main {
  static void timeStamp(String msg, PrintWriter pw) {
    Calendar cal = Calendar.getInstance();
    pw.printf("%s %tc\n", msg, cal);
  }

  public static void main(String args[]) throws Exception {

    PrintWriter pw = new PrintWriter(new FileWriter("logfile.txt", true));
    timeStamp("File opened", pw);
    pw.close();
    if (pw.checkError())
      System.out.println("I/O error occurred.");
  }
}

Related examples in the same category

1.	give a known Locale (with the right decimal separator) to bypass the current Locale
2.	Two decimal digits
3.	Group separators
4.	Align string output
5.	Align float numbers
6.	Display current time
7.	Display short and long date and time formats.
8.	"%d %(d %+d %05d
9.	System.out.printf("a %1$s is a %1$s is a %1$s...", "AAA")
10.	System.out.printf( "%-10.10s %s\n", word, word.length() )
11.	System.out.printf("num is %s\n", 5)
12.	System.out.printf("The DATE is %tz\n", new Date() )
13.	System.out.printf("%1$s://%2$s/%3$s\n", "http", "host", "path")
14.	System.out.printf("num is %.2f\n", Math.PI )
15.	System.out.printf("String is '%-5s'\n", "A")
16.	System.out.printf(Locale.CHINA, "The date is %tc\n", new Date())
17.	System.out.printf("The DATE is %tr\n", new Date() )
18.	System.out.printf("The DATE is %Tc\n", new Date() )
19.	System.out.printf("%s://%s/%s\n", "http", "host", "path")
20.	System.out.printf("num is %03d\n", 5 )
21.	System.out.printf("num is {%07.3f}\n", 3.14 )
22.	System.out.printf("1.0 4f num is %4f\n", 1.0 )
23.	System.out.printf("sci not num is %e\n", 3000000.0 )
24.	System.out.printf("boolean value is %1$b, %1$B\n", true )
25.	System.out.printf("hex value is %1$#x, %1$#X\n", 0xCAFE )
26.	System.out.printf( Locale.ITALIAN, "value: %f\n", 3.14 )
27.	System.out.printf("float is %-20f!\n", 1.23456789)
28.	Use printf(): Two decimal digits
29.	Use printf(): group separators
30.	Use printf(): %10s %10s %10s
31.	Use printf(): align float numbers
32.	Default floating-point format: %f
33.	Floating-point with commas: %,f
34.	Negative floating-point default: %,f
35.	Negative floating-point option: %,(f
36.	Line up positive and negative values
37.	System.out.format("%f, %1$+020.10f %n", Math.PI)
38.	System.out.printf("%b %n %c %n %s %n %s %n %d %n",..)
39.	Basic Math with System.out.printf
40.	Display a file in hex.

Use printf() to create a time stamp. : printf « Development Class « Java

Related examples in the same category