集合与map迭代

//ArrayList
List list1 = new ArrayList();
Address address1 = new Address("中国","上海");
Address address2 = new Address("美国","纽约");
Address address3 = new Address("日本","冲绳");
list1.add(address1);
list1.add(address2);
list1.add(address3);
for(int i = 0; i < list1.size();i++){
Address address = (Address)list1.get(i);
System.out.println(address.getCountry()+"--------"+address.getCity());
}
//LinkedList
List list2 = new LinkedList();
Address address4 = new Address("中国","上海");
Address address5 = new Address("美国","纽约");
Address address6 = new Address("日本","冲绳");
list2.add(address4);
list2.add(address5);
list2.add(address6);
for(int i = 0; i < list2.size();i++){
Address address = (Address)list2.get(i);
System.out.println(address.getCountry()+"*******"+address.getCity());
}
//set foreach迭代 判断非空 空指针异常
Set set1 = new HashSet();
Address address7 = new Address("中国","上海");
Address address8 = new Address("美国","纽约");
Address address9 = new Address("日本","冲绳");
set1.add(address7);
set1.add(address8);
set1.add(address9);
for(Object obj: set1){
Address address = (Address)obj;
System.out.println(address.getCountry()+"======="+address.getCity());
}
//Iterator迭代
Iterator it = set1.iterator();
while(it.hasNext()){
Address address=(Address)it.next();
System.out.println(address.getCountry()+"_______"+address.getCity());
}

Map map = new HashMap();
map.put("CN","中国");
map.put("US","美国");
map.put("RU","俄罗斯");
//key的集合是set
System.out.println(map.keySet());
//value的集合是Collection
System.out.println(map.values());
//keySet()
Set key1 = map.keySet();
//循环拿到所有的键
Iterator iterator = key1.iterator();
while(iterator.hasNext()){
String key2 = (String)iterator.next();
String value = (String)map.get(key2);
System.out.println(key2+"-----"+value);
}
//entrySet()--Set(Map.Entry)
//增强for或迭代器Iterator
Set  set3 = map.entrySet();
for(Object obj: set3){
String key = (String)((Map.Entry)obj).getKey();
String value = (String)((Map.Entry)obj).getValue();
System.out.println(key+"-----"+value);

}

//用keySet()也可以

Iterator it3 = set3.iterator();
while(iterator.hasNext()){
String key = (String)((Map.Entry)iterator.next()).getKey();
String value = (String)((Map.Entry)iterator.next()).getValue();
System.out.println(key+"-----"+value);
}

//map.values()遍历

List valuesList = new ArrayList(map.values());

for(Object str:valuesList){

  System.out.println(str);

}

Set<Map.Entry<Integer, Iphone>> set = map.entrySet();
for(Map.Entry<Integer,Iphone> m: set){
System.out.print(m.getKey()+"=====");
System.out.println(m.getValue());
}