常见集合类的遍历

ArrayList

List<String> list = new ArrayList<>();
list.add("a");
list.add("b");
list.add("d");

Iterator<String> ite = list.iterator();
while(ite.hasNext()) {
    System.out.print(ite.next() + "\t");
}

// ListIterator 专门用来遍历List的
ListIterator<String> listite = list.listIterator();
while (listite.hasNext()) {
    String str = listite.next();
    System.out.println(str);
}

// -----------------------------        
for (String str : list) {
    System.out.print(str + "\t");
}

LinkedList

List<String> link = new LinkedList<>();
link.add("e");
link.add("f");
link.add("g");

Iterator<String> ite = link.iterator();
while(ite.hasNext()) {
    System.out.print(ite.next() + "\t");
}

for (String str : link) {
    System.out.print(str + "\t");
}

Set

Set<String> sets = new HashSet<>();
sets.add("z");
sets.add("x");
sets.add("c");

Iterator<String> setIte = sets.iterator();
while (setIte.hasNext()) {
    String string = (String) setIte.next();
    System.out.println(string);
}

Map

Map<Integer, String> map = new HashMap<>();
map.put(1, "a");
map.put(2, "b");
map.put(3, "c");
        
Set<Entry<Integer, String>> set = map.entrySet();
Iterator<Entry<Integer, String>> iterator =  set.iterator();
while (iterator.hasNext()) {
    Map.Entry<Integer, String> entry = (Map.Entry<Integer, String>) iterator.next();
    String value = entry.getValue();
    Integer key = entry.getKey();
    System.out.println(key + "=" + value);
}

for (Entry<Integer, String> entry : map.entrySet()) {
    System.out.println(entry.getKey() + "=" + entry.getValue());
}