对Java8 stream的简单实践

最近学习很多Java8方面的新特性，特地做了一些简单的实践和总结。

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);
}
}