除了显式使用循环之外，对于 List列出你可以做的:

Aside from using loops explicitly, for List<Integer> list you can do:

int sum = list.stream().mapToInt(Integer::intValue).sum();

如果它是一个 int[] ar 然后做:

If it's an int[] ar then do:

int sum = IntStream.of(ar).sum();

这是基于流的使用.

或者你可以做这个简单的单线循环:

Or you can do this simple one liner loop:

int sum = 0;
for (Integer e : myList) sum += e;

更好的是，编写一个函数并重用它:

Even better, write a function and reuse it:

public int sum(List<Integer> list) {
    int sum = 0;
    for (Integer e : list) sum += e;

    return sum;
}