java8 list和map的forEach详解编程语言

public class HelloWorld { 
    public static void main(String[] args) { 
        List<User> list = new ArrayList<>(); 
        for(int i=1;i<=10;i++) { 
            list.add(new User(i, "user_" + i)); 
        } 
        //list forEach 
        list.forEach(user -> { 
            user.setId(user.getId() + 10); 
            System.out.println(user); 
        }); 
 
    } 
    private static class User{ 
        public User(Integer id, String name) { 
            this.id = id; 
            this.name = name; 
        } 
 
        Integer id; 
        String name; 
 
        public Integer getId() { 
            return id; 
        } 
 
        public void setId(Integer id) { 
            this.id = id; 
        } 
 
        public String getName() { 
            return name; 
        } 
 
        public void setName(String name) { 
            this.name = name; 
        } 
 
        @Override 
        public String toString() { 
            return "User{" + 
                    "id=" + id + 
                    ", name='" + name + '/'' + 
                    '}'; 
        } 
    } 
 
}

User{id=11, name='user_1'} 
User{id=12, name='user_2'} 
User{id=13, name='user_3'} 
User{id=14, name='user_4'} 
User{id=15, name='user_5'} 
User{id=16, name='user_6'} 
User{id=17, name='user_7'} 
User{id=18, name='user_8'} 
User{id=19, name='user_9'} 
User{id=20, name='user_10'}

public class HelloWorld { 
    public static void main(String[] args) { 
        Map<Integer, User> map = new HashMap<>(10); 
        for(int i=1;i<=10;i++) { 
            map.put(i, new User(i, "user_" + i)); 
        } 
        //map forEach 
        map.forEach((k, v) -> { 
            System.out.println("key: " + k + ", value:" + v); 
        }); 
 
    } 
    private static class User{ 
        public User(Integer id, String name) { 
            this.id = id; 
            this.name = name; 
        } 
 
        Integer id; 
        String name; 
 
        public Integer getId() { 
            return id; 
        } 
 
        public void setId(Integer id) { 
            this.id = id; 
        } 
 
        public String getName() { 
            return name; 
        } 
 
        public void setName(String name) { 
            this.name = name; 
        } 
 
        @Override 
        public String toString() { 
            return "User{" + 
                    "id=" + id + 
                    ", name='" + name + '/'' + 
                    '}'; 
        } 
    } 
 
}

key: 1, value:User{id=1, name='user_1'} 
key: 2, value:User{id=2, name='user_2'} 
key: 3, value:User{id=3, name='user_3'} 
key: 4, value:User{id=4, name='user_4'} 
key: 5, value:User{id=5, name='user_5'} 
key: 6, value:User{id=6, name='user_6'} 
key: 7, value:User{id=7, name='user_7'} 
key: 8, value:User{id=8, name='user_8'} 
key: 9, value:User{id=9, name='user_9'} 
key: 10, value:User{id=10, name='user_10'}