准备数据

java"> ArrayList<Integer> list = new ArrayList<Integer>();for (int i = 0; i < 100000000; i++) {list.add(i);
}

1.for循环

java"> for (int i = 0; i < list.size(); i++) {Integer str = list.get(i);
}

2.for-each循环

java"> for (Integer vo:list) {}

3.Lambda

java"> list.forEach(u->{});

迭代器

java">Iterator<Integer> itr = list.iterator();while(itr.hasNext()){Integer str = itr.next();}

for循环耗时106毫秒，for-each循环耗时103毫秒，Lambda耗时122毫秒，迭代器耗时100毫秒
从结果看出，for循环、for-each循环、迭代器差不多，Lambda耗时最长