Java 集合List Set Map 循环的遍历 EnumMap集合的操作

1：List集合遍历的方式（ArrayList为例）
1.1 实体类
public class User {
private String username;
private String address;
private int age;

public User() {
    super();
}
public User(String username, String address, int age) {
    super();
    this.username = username;
    this.address = address;
    this.age = age;
}
public String getUsername() {
    return username;
}
public void setUsername(String username) {
    this.username = username;
}
public String getAddress() {
    return address;
}
public void setAddress(String address) {
    this.address = address;
}
public int getAge() {
    return age;
}
public void setAge(int age) {
    this.age = age;
}
@Override
public String toString() {
    return "User [username=" + username + ", address=" + address + ", age=" + age + "]";
}

}
1.2向集合中添加User对象
List list=new ArrayList<>();

    List list1=new ArrayList<>();

    User user1=new User("刘备","今河北省保定市涿州市",1800);
    User user2=new User("张飞","河北",1800);
    User user3=new User("关羽","山西解梁",1800);
    User user4=new User("赵云","河北常山",1800);
    User user5=new User("诸葛亮","河南南阳",1800);

    list.add(user1);
    list.add(user2);
    list.add(user3);
    list.add(user4);
    list.add(user5);
    System.out.println("list集合foreach循环");
    for (User user : list) {

        if(user.getUsername().equals("刘备")){
            user.setAddress("搬迁到四川成都成为蜀国的君王");
        }
        System.out.println("姓名："+user.getUsername()+",户籍："+user.getAddress()+
                ",年龄："+user.getAge());
    }

    System.out.println("list集合for循环");
    for(int i=0;i it=list1.iterator();

    while(it.hasNext()){
        System.out.println(it.next());
    }

    System.out.println("list集合Lamda循环");
    list.forEach(l->System.out.println(l));

2：Set集合的遍历（HashSet为例，不能使用for循环遍历）
Set set = new HashSet<>();
User user1 = new User(“刘备”, “今河北省保定市涿州市”, 1800);
User user2 = new User(“张飞”, “河北”, 1800);
User user3 = new User(“关羽”, “山西解梁”, 1800);
User user4 = new User(“赵云”, “河北常山”, 1800);
User user5 = new User(“诸葛亮”, “河南南阳”, 1800);
set.add(user1);
set.add(user2);
set.add(user3);
set.add(user4);
set.add(user5);
System.out.println(“set集合foreach循环”);
for (User user : set) {
if (user.getUsername().equals(“刘备”)) {
user.setAddress(“搬迁到四川成都成为蜀国的君王”);
}
System.out.println(“姓名：” + user.getUsername() + “,户籍：” + user.getAddress() + “,年龄：” + user.getAge());
}
System.out.println(“set集合Iterator”);
if (set.isEmpty()) {
System.out.println(“set1集合为空”);
}
Iterator it = set.iterator();
while (it.hasNext()) {
System.out.println(it.next());
}
System.out.println(“set集合Lamda循环”);
set.forEach(l -> System.out.println(l));
3：Map集合的遍历（HashMap为例）
Map