常见集合的循环输出方式一、List 集合的循环输出List objList = new ArrayList();1) for (int i=0; i list = new ArrayList();list.add(cheng);list.add(zhang);Iterator it = list.iterator(); while (it.hasNext()String str = (String)it.next();System.out.println(str);4) 将 List 集合转换为 Object 类型的数组,循环输出List list = new ArrayList();list.add(cheng);list.add(zeng);list.add(zhang);Object obj = list.toArray();for (int i=0; i 1) 将 Set 集合转换为迭代器 Iterator 接口，并且循环输出Set set = new HashSet();set.add(cheng);set.add(zeng);set.add(zhang); Iterator it = set.iterator();while (it.hasNext()String str = (String)it.next();System.out.println(str);2) 将 Set 集合转换为 Object 类型的数组Set set = new HashSet();set.add(cheng);set.add(zeng);set.add(zhang);Object obj = set.toArray();for (int i=0;i1) 直接循环 Map 对象Map map = new HashMap();map.put(1,cheng);map.put(2,zeng);map.put(3,zhang);/ 输出键值 for (String key:map.keySet()System.out.println(key);/ 输出 valuefor (String value:map.values()System.out.println(value);2) Map map = new HashMap();map.put(1,cheng);map.put(2,zeng);map.put(3,zhang);Iterator it = map.entrySet().iterator();while (it.hasNext()Map.Entry s = (Map.Entry)it.next();System.out.println(s);输出结果：3=zhang2=zeng1=cheng