lambda表达式中的stream流

在我们日常开发中,对集合的操作一直是一个非常常见的操作,在jdk8之前,我们一般都会采用遍历的方式,来实现对集合中每一个元素进行操作,jdk8之后我们有更好的选择----stream流

package main.java.test;

import com.google.common.collect.Lists;
import main.java.test.pojo.User;

import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;

/**
 * @ClassName : TestName
 * @Author : YiBin
 * @CreateTime : 2018/9/7 14:07
 */
public class TestName {
    public static void main(String[] args) {
        ArrayList<User> users = Lists.newArrayList(
                new User("sara", "18", "123456787", "上海"),
                new User("sara", "18", "123456788", "上海"),
                new User("sara", "18", "123456789", "上海"),
                new User("sara", "18", "123456789", "上海"));
        
        //去除集合中有某一项属性值相同的对象
        ArrayList<User> result = new ArrayList<>();
        for (User user : users) {
            if (result.stream().noneMatch(item->item.getPhone().equals(user.getPhone()))) {
                result.add(user);
            }
        }
        result.stream().forEach(System.out::println);
/**
 *User{name='sara', age='18', phone='123456787', address='上海'}
 *User{name='sara', age='18', phone='123456788', address='上海'}
 *User{name='sara', age='18', phone='123456789', address='上海'}
 */


        //过滤集合中指定属性值得对象
        users.stream().filter(item->item.getPhone().equals(users.get(0).getPhone())==false).forEach(System.out::println);
/**
 *User{name='sara', age='18', phone='123456788', address='上海'}
 *User{name='sara', age='18', phone='123456789', address='上海'}
 *User{name='sara', age='18', phone='123456789', address='上海'}
 */

        //将一根集合转换位另一个集合
        List<String> phone = users.stream().map(i -> i.getPhone()).distinct().collect(Collectors.toList());

    }
}

暂时就学会这么多

lambda表达式中的stream流

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