import java.util.ArrayList;import java.util.List;import java.util.UUID;import java.util.concurrent.TimeUnit;public class StreamTest9 {    public static void main(String[] args) {        List
     
       list = new ArrayList<>(5000000);        for(int i = 0; i < 5000000; ++i) {            list.add(UUID.randomUUID().toString());        }        System.out.println("开始排序");        long startTime = System.nanoTime();        // 为何提示sorted方法是不必要的？        list.parallelStream().sorted().count();        long endTime = System.nanoTime();        long millis = TimeUnit.NANOSECONDS.toMillis(endTime - startTime);        System.out.println("排序耗时：" + millis);    }}
     

import java.util.Arrays;import java.util.List;public class StreamTest10 {    public static void main(String[] args) {        List
     
       list = Arrays.asList("hello1", "world", "hello world");//        list.stream().mapToInt(item -> item.length()).filter(length -> length == 5).//                findFirst().ifPresent(System.out::println);        list.stream().mapToInt(item -> {            int length = item.length();            System.out.println(item);            return length;        }).filter(length -> length == 5).findFirst().ifPresent(System.out::println);    }}
     

import java.util.Arrays;import java.util.List;import java.util.stream.Collectors;public class StreamTest11 {    public static void main(String[] args) {        List
     
       list = Arrays.asList("hello welcome", "world hello",                "hello world hello", "hello welcome");//        List
      
        result = list.stream().map(item -> item.split(" ")).distinct().//                collect(Collectors.toList());//        result.forEach(item -> Arrays.asList(item).forEach(System.out::println));        List
       
         result = list.stream().map(item -> item.split(" ")).flatMap(Arrays::stream).distinct().                collect(Collectors.toList());        result.forEach(System.out::println);    }}
       
      
     

import java.util.Arrays;import java.util.List;import java.util.stream.Collectors;public class StreamTest12 {    public static void main(String[] args) {        List
     
       list1 = Arrays.asList("Hi", "Hello", "你好");        List
      
        list2 = Arrays.asList("zhangsan", "lisi", "wangwu", "zhaoliu");        List
       
         result = list1.stream().flatMap(item -> list2.stream().map(item2 -> item + " " + item2)).                collect(Collectors.toList());        result.forEach(System.out::println);    }}
       
      
     

import java.util.Arrays;import java.util.List;import java.util.Map;import java.util.stream.Collectors;public class StreamTest13 {    public static void main(String[] args) {        Student student1 = new Student("zhangsan", 100, 20);        Student student2 = new Student("lisi", 90, 20);        Student student3 = new Student("wangwu", 90, 30);        Student student4 = new Student("zhangsan", 80, 40);        List
     
       students = Arrays.asList(student1, student2, student3, student4);//        Map
      
       > map = students.stream().//                collect(Collectors.groupingBy(Student::getName));//        Map
       
        > map = students.stream().//                collect(Collectors.groupingBy(Student::getScore));//        Map
        
          map = students.stream().//                collect(Collectors.groupingBy(Student::getName, Collectors.counting()));//        Map
         
           map = students.stream().//                collect(Collectors.groupingBy(Student::getName, Collectors.averagingDouble(Student::getScore)));//        Map
          
           > map = students.stream().// collect(Collectors.partitioningBy(student -> student.getScore() >= 90));// System.out.println(map); }}
          
         
        
       
      
     

public class Student {    private String name;    private int score;    private int age;    public Student(String name, int score, int age) {        this.name = name;        this.score = score;        this.age = age;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public int getScore() {        return score;    }    public void setScore(int score) {        this.score = score;    }    public int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }}