Iterator在List、Set、Map中的用法

List

public static void main(String[] args) {
    List<String> list = new ArrayList<>();
    list.add("0");
    list.add("1");
    list.add("2");
    Iterator<String> iterator = list.iterator();
    while (iterator.hasNext()) {
        System.out.println(iterator.next());
    }
}

Set

public static void main(String[] args) {
    Set<String> set = new HashSet<>();
    set.add("0");
    set.add("1");
    set.add("2");
    Iterator<String> iterator = set.iterator();
    while (iterator.hasNext()) {
        System.out.println(iterator.next());
    }
}

Map

public static void main(String[] args) {
    Map<String, String> map = new HashMap<>();
    map.put("k0", "v0");
    map.put("k1", "v1");
    map.put("k2", "v2");
    Iterator<Map.Entry<String, String>> iterator = map.entrySet().iterator();
    while (iterator.hasNext()) {
        Map.Entry<String, String> entry = iterator.next();
        System.out.println(entry.getKey() + "," + entry.getValue());
    }
}