imsavva.com

Using one DateFormat instance per thread with ThreadLocal

Here is a quick tip how to use DateFormat inside a ThreadLocal field. Why do we need that? The reason is the DateFormat class is not thread-safe but creating its instances is an expensive operation. So, this is kind of a workaround that creates only one instance of DateFormat per thread.

package com.imsavva.test;
import java.text.SimpleDateFormat;
import java.util.Date;
/**
* @author Savva Kodeikin
*/
public class ThreadLocalDateFormatTest {
private static ThreadLocal<SimpleDateFormat> dateFormat = new ThreadLocal<SimpleDateFormat>() {
@Override
protected SimpleDateFormat initialValue() {
return new SimpleDateFormat("dd/MM/yyyy");
}
};
public String formatDate(Date date) {
return dateFormat.get().format(date);
}
}
Posted on 2017-07-12
Do I really need the footer?