关于常量的测试(Java1.6)

package test;

import java.util.Calendar;

public class Test {

    private static final String AAA = "aaa";

    /**
     * @param args
     */
    public static void main(String[] args) {
        long startTime;
        long endTime;
        System.out.println("Constant :");
        startTime = Calendar.getInstance().getTimeInMillis();
        for (int i = 0; i < 999999999; i++) {
            String a = AAA;
        }
        endTime = Calendar.getInstance().getTimeInMillis();
        System.out.println(endTime - startTime);

        System.out.println();

        System.out.println("Variable :");
        startTime = Calendar.getInstance().getTimeInMillis();
        for (int i = 0; i < 999999999; i++) {
            String a = "a";
        }
        endTime = Calendar.getInstance().getTimeInMillis();
        System.out.println(endTime - startTime);

    }

}

 

 

结果

 

Constant :
1297

Variable :
1265

 

所以使用常量只是能提高代码重用性，并提高后期维护型，没有效率可言