ArrayList遍历:
public class Test{ public static void main(String[] args) { List<String> list = new ArrayList<String>(); list.add("abc"); list.add("def"); list.add("ghi"); //使用foreach遍历 for(String s : list){ System.out.println(s); } //变为普通数组遍历 String[] array = new String[list.size()]; list.toArray(array); for(String s : array){ System.out.println(s); } //使用迭代器(iterator)进行遍历 Iterator<String> iterator= list.iterator(); while(iterator.hasNext()){ System.out.println(iterator.next()); } } }
LinkedList遍历:与ArrayList基本一致
Map遍历:
public class Test{ public static void main(String[] args) { Map<String,String> map = new HashMap<String, String>(); map.put("1","value1"); map.put("2","value2"); map.put("3","value3"); //通过keySet遍历 for(String key : map.keySet()){ System.out.println(key + ":" + map.get(key)); } //通过iterator遍历 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()); } //通过Map,entrySet使用foreach遍历 for(Map.Entry<String,String> entry : map.entrySet()){ System.out.println(entry.getKey() + ":" + entry.getValue()); } //通过map.Values()遍历所有的value,但不能遍历key for(String v : map.values()){ System.out.println(v); } } }
Set遍历:
public class Test{ public static void main(String[] args) { Set<String> set = new HashSet<String>(); set.add("s1"); set.add("s2"); set.add("s3"); //普通的foreach遍历 for(String s : set){ System.out.println(s); } Iterator<String> iterator = set.iterator(); while(iterator.hasNext()){ String s = iterator.next(); System.out.println(s); } } }