刚看的有点用.增强的FOR循环;

User是自定义的object
users是List <User>变量

for (User user: users) {
    System.out.println(user.name);
    System.out.println(user.brithday);
}

当然你可也以写成
for (int i=0; i <users.size(); i++) {
    User user = users.get(i);
    System.out.println(user.name);
    System.out.println(user.brithday);
}