import java.util.*; 
import java.util.stream.Collectors; 
 
public class StreamTest { 
    static class User{ 
        private String name; 
        private int age; 
 
        public String getName() { 
            return name; 
        } 
 
        public void setName(String name) { 
            this.name = name; 
        } 
 
        public int getAge() { 
            return age; 
        } 
 
        public void setAge(int age) { 
            this.age = age; 
        } 
 
        public User(String name, int age) { 
            this.name = name; 
            this.age = age; 
        } 
 
        @Override 
        public String toString() { 
            return name; 
        }
 
// 重写hashCode 
        @Override 
        public int hashCode() { 
            int n = 31; 
            n = n * 31 + age; 
            n = n* 31 + name.hashCode(); 
            return n; 
 
        } 
 
        @Override 
        public boolean equals(Object obj) { 
            if (!(obj instanceof User)) { 
                return false; 
            } 
            User user1 = (User) obj; 
            return this.name.equals(user1.name) 
                    && Integer.valueOf(age).equals(user1.age); 
        } 
    } 
    public static void main(String[] args) { 
        List<User> list = new ArrayList<>(); 
        User user1 = new User("zdx", 12); 
        User user2 = new User("zdx1", 12); 
        User user3 = new User("zdx2", 18); 
        User user4 = new User("zdx3", 22); 
        list.add(user1); 
        list.add(user2); 
        list.add(user3); 
        list.add(user4); 
 
        // 将 Stream 转化为List 并且实现去重 
        List list1 = list.stream().distinct().collect(Collectors.toList()); 
        list1.forEach(System.out::println); 
 
        // 将 Stream 转化为 Map 
        // 实现此方法需要注意添加进Map的的 key 值不可以重复，否则会抛出异常！！！！ 
        Map<String, Integer> map = list.stream().collect(Collectors.toMap(User::getName, User::getAge)); 
        for (String key: map.keySet()) { 
            System.out.println(key); 
        } 
 
 
//         去重实现方法一 
        List<User> result = new LinkedList<>(); 
        for (User user : list) { 
            boolean b = result.stream().anyMatch(u -> u.name.equals(user.name)); 
            if (!b) { 
                result.add(user); 
            } 
        } 
 
        result.forEach(System.out::println); 
 
 
//         利用HashSet实现list的去重 
        Set<User> set = new HashSet<>(list); 
        set.forEach(System.out::println); 
    } 
}