遍历list集合的三种方式

Posted 2020-10-07 Jade

        List<String> list1 = new ArrayList<String>();
        list1.add("1");
        list1.add("2");
        list1.add("3");
        list1.add("4");
        // 1、普通话for循环
        String res = "";
        for (int i = 0; i < list1.size(); i++) {
            res += list1.get(i);
        }
        System.out.println(res);
        // 2、增强for
        String res2 = "";
        for (String item : list1) {
            res2 += item;
        }
        System.out.println(res2);
        // 3、使用迭代器遍历
        Iterator<String> it = list1.iterator();
        String res3 = "";
        while (it.hasNext()) {
            res3 += it.next();
        }
        System.out.println(res3);