Java基础__学习笔记__Steam流

stream流看API数据处理文档

流只能使用一次，应该严格定义为被使用一次

package SteamDemo;

import java.awt.List;
import java.util.*;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.stream.Stream;

public class StreamDemo1 {
    public static void main(String[] args) {
        /**
         * Collection集合获取流
         */
        Collection<String> list = new ArrayList<>();
        Stream<String> arrstream = list.stream();


        /**
         * Map集合获取流
         */
        Map<String, Integer> map = new HashMap<>();
        //键流
        Stream<String> keystream = map.keySet().stream();

        //值流
        Stream<Integer> valuestream = map.values().stream();

        //键值流
        Stream<Map.Entry<String, Integer>> keyandvaluestream = map.entrySet().stream();


        /**
         * 数组获取流
         */
        String[] name = {"陈明旭", "罗昊", "卢毅"};
        Stream<String> namestream = Arrays.stream(name);
        Stream<String> namestream2 = Stream.of(name);


        namestream.filter((String s) -> s.length() == 2).distinct().forEach(s -> System.out.println(s));
//        namestream.filter(s-> s.length() == 2).distinct().forEach(s -> System.out.println(s));


        Arrays.stream(name).filter((String s) -> s.startsWith("罗")).distinct().forEach(s -> System.out.println(s));



        Collection<String> list1 = new ArrayList<>();
        Collections.addAll(list1,"陈明旭", "罗昊", "卢毅");
        //map加工方法 可以在
        list1.stream().map(s -> "男同"+s.length()+":"+s ).forEach(s -> System.out.println(s));





    }

}