Map<Integer,User> map=new HashMap<Integer,User>();
map.put(1001, new User(1001,"孙悟空d","123"));
map.put(1002, new User(1002,"孙悟空a","dfa"));
map.put(1003, new User(1003,"孙悟空b","55"));
map.put(1004, new User(1004,"孙悟空c","888"));
//第一种循环,把map看成由key的集合与value的集合
Set<Integer> keySet=map.keySet();
for(Integer key:keySet){
User u=map.get(key);
System.out.println(key+"==>"+u.getLoginName());
}
System.out.println("------------------------------");
//如果不适用key的情况
Collection<User> values=map.values();
for(User u:values){
System.out.println(u.getLoginName());
}
System.out.println("------------------------------");
//第二种循环,把map看成为entry的集合
Set<Entry<Integer, User>> entries=map.entrySet();
for(Entry<Integer, User> entry:entries){
Integer key=entry.getKey();
User value=entry.getValue();
System.out.println("key="+key+"==>value:"+value.getLoginName());
}
map.put(1001, new User(1001,"孙悟空d","123"));
map.put(1002, new User(1002,"孙悟空a","dfa"));
map.put(1003, new User(1003,"孙悟空b","55"));
map.put(1004, new User(1004,"孙悟空c","888"));
//第一种循环,把map看成由key的集合与value的集合
Set<Integer> keySet=map.keySet();
for(Integer key:keySet){
User u=map.get(key);
System.out.println(key+"==>"+u.getLoginName());
}
System.out.println("------------------------------");
//如果不适用key的情况
Collection<User> values=map.values();
for(User u:values){
System.out.println(u.getLoginName());
}
System.out.println("------------------------------");
//第二种循环,把map看成为entry的集合
Set<Entry<Integer, User>> entries=map.entrySet();
for(Entry<Integer, User> entry:entries){
Integer key=entry.getKey();
User value=entry.getValue();
System.out.println("key="+key+"==>value:"+value.getLoginName());
}