public static void main(String[] args) {ui
Map<String, String> map = new HashMap<String, String>();
map.put("1", "value1");
map.put("2", "value2");
map.put("3", "value3");
//第一种：广泛使用，二次取值
System.out.println("经过Map.keySet遍历key和value：");
for (String key : map.keySet()) {
System.out.println("key= "+ key + " and value= " + map.get(key));
}
//第二种
System.out.println("经过Map.entrySet使用iterator遍历key和value：");
Iterator<Map.Entry<String, String>> it = map.entrySet().iterator();
while (it.hasNext()) {
Map.Entry<String, String> entry = it.next();
System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());
}
//第三种：推荐，尤为是容量大时
System.out.println("经过Map.entrySet遍历key和value");
for (Map.Entry<String, String> entry : map.entrySet()) {
System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());
}spa
//第四种
System.out.println("经过Map.values()遍历全部的value，但不能遍历key");
for (String v : map.values()) {
System.out.println("value= " + v);
}
}get
-----------------------------------------it
public class ArrayListDemo {class
public static void main(String args[]){List
List<String> list = new ArrayList<String>();遍历
list.add("luojiahui");map
list.add("luojiafeng");方法
//方法1next
Iterator it1 = list.iterator();
while(it1.hasNext()){
System.out.println(it1.next());
}
//方法2 怪异！
for(Iterator it2 = list.iterator();it2.hasNext();){
System.out.println(it2.next());
}
//方法3
for(String tmp:list){
System.out.println(tmp);
}
//方法4
for(int i = 0;i < list.size(); i ++){
System.out.println(list.get(i));
}
}
}