public static void main(String[] args) {
ArrayList<Long> l = new ArrayList<>(7500001);
long start= System.currentTimeMillis();
for(int i =0 ; i < 5000000; i ++){
long now = new Date().getTime();
l.add(now);
}
System.out.println("new date cost [" + (System.currentTimeMillis()- start) + "] ms");
l.clear();
start= System.currentTimeMillis();
for(int i =0 ; i < 5000000; i ++){
long now = System.currentTimeMillis();
l.add(now);
}
System.out.println("System.currentTimeMillis cost [" + (System.currentTimeMillis()- start) + "] ms");
l.clear();
}
结果：
new date cost [1842] ms System.currentTimeMillis cost [391] ms
new Date().getTime()和System.currentTimeMillis()效率对
原文：http://my.oschina.net/kanlianhui/blog/507471