方法引用和Stream和时间

package wang;

import java.awt.*;
import java.lang.reflect.Array;
import java.util.*;
import java.util.List;
import java.util.function.BiFunction;
import java.util.function.Function;
import java.util.function.Supplier;
import java.util.stream.Collector;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

public class dome {
    public static void main(String[] args) {
        List<Person> personList = new ArrayList<>();
        personList.add(new Person("欧阳雪",18,"中国",'F'));
        personList.add(new Person("Tom",24,"美国",'M'));
        personList.add(new Person("Harley",22,"英国",'F'));
        personList.add(new Person("向天笑",20,"中国",'M'));
        personList.add(new Person("李康",22,"中国",'M'));
        personList.add(new Person("小梅",20,"中国",'F'));
        personList.add(new Person("何雪",21,"中国",'F'));
        personList.add(new Person("李康",22,"中国",'M'));
        //findFirst match
       // Optional<Person> first = personList.stream().filter(item -> item.getSex() == 'M').findFirst();
      /*  boolean b = personList.stream().filter(item -> item.getSex() == 'M').allMatch(item -> item.getAge() > 20);//所有都满足

        System.out.println(b);*/

      /*  Supplier<Person> supplier = ()->{
            return new Person();
        };*/
        Supplier<Person> supplier = ()->{
            return new Person();
        };
        System.out.println(supplier.get());

        //对象方法的引用
        //Function<String,Integer> function = item->item.length();
       /* Function<String, Integer> function = String::length;
        System.out.println(function.apply("niihao"));*/
        //比较两个字符串是否相等
       /* BiFunction<String,String,Boolean> biFunction = (t,u)->{
            return t.equals(u);
        };*/
        /* BiFunction<String,String,Boolean> biFunction = String::equals;
        System.out.println(biFunction.apply("haha","heihei"));*/
        //collect搜索终止
        //求年龄大于20且性别为M
        /*List<Person> collect = personList.stream()
                .filter(item -> item.getAge() > 20)
                .filter(item -> item.getSex() == 'M')
                .collect(Collectors.toList());
        System.out.println(collect);*/
        //求集合中年龄的和
        /*Optional<Integer> reduce = personList.stream()
                .map(item -> item.getAge())
                .reduce((a, b) -> a + b);*/
       /* Integer reduce = personList.stream()
                .map(item -> item.getAge())
                .reduce(10, (a, b) -> a + b);
        System.out.println(reduce);*/
        //查找最大值
        /*Optional<Person> max = personList.stream()
                .max((o1, o2) -> o1.getAge() - o2.getAge());
        System.out.println(max.get());*/
        //按照年龄排序
        /*personList.stream()
                .sorted(((o1, o2) -> o1.getAge()- o2.getAge()))
                .forEach(System.out::println);*/

       /* boolean b = personList.stream().filter(item -> item.getAge() > 20).allMatch(item -> item.getSex() == 'M');
        System.out.println(b);*/


        /*Optional<Integer> reduce = personList.stream().map(item -> item.getAge()).reduce((a, b) -> a + b);
        System.out.println(reduce.get());*/

        //personList.stream().filter(item->item.getAge()==18).forEach(item-> System.out.println(item));
        /*personList.stream().map(item->{
            Map map = new HashMap();
            map.put("name",item.getName());
            map.put("age",item.getAge());
            return map;
        }).forEach(System.out::println);*/

    /*    ArrayList<String> list = new ArrayList<>();
        Collections.addAll(list, "张无忌", "周芷若", "赵敏", "张强", "张三丰","何线程");
        list.stream()
                .filter(item->item.startsWith("张"))
                .filter(item->item.length()==3)
                .forEach(item-> System.out.println(item));
        int[] arr={2,1,23,1,5,4};
        IntStream stream = Arrays.stream(arr);
                stream.forEach(item-> System.out.println(item));*/
    }
}
class Person {
    private String name;
    private Integer age;
    private String country;
    private char sex;

    public Person() {
    }

    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", country='" + country + '\'' +
                ", sex=" + sex +
                '}';
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public String getCountry() {
        return country;
    }

    public void setCountry(String country) {
        this.country = country;
    }

    public char getSex() {
        return sex;
    }

    public void setSex(char sex) {
        this.sex = sex;
    }

    public Person(String name, Integer age, String country, char sex) {
        this.name = name;
        this.age = age;
        this.country = country;
        this.sex = sex;
    }
}

package date;

import java.time.Duration;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;

public class dome {
    public static void main(String[] args) {
        LocalDate now = LocalDate.now();//当前日期
        LocalDate of = LocalDate.of(2020,1,2);//自定义日期
        LocalTime now1 = LocalTime.now();//当前时间
        LocalTime of1 = LocalTime.of(12, 25, 12,16546);//自定义时间
        LocalDateTime now2 = LocalDateTime.now();//当前日期时间
        LocalDateTime of2 = LocalDateTime.of(2020, 5, 4, 12, 12, 12, 12);//自定义日期时间
        Duration between = Duration.between(of2, now2);//时间差Duration
        DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd");//自定义类型
        LocalDate parse = LocalDate.parse("2021-12-11", dateTimeFormatter);//字符串转日期
        String format = parse.format(dateTimeFormatter);//日期转字符串

        System.out.println(between.toDays());
    }
}