Java 09 函数式接口

 

消费者 consumer

import org.junit.Test;

import java.util.function.Consumer;

public class consumer {
    public void test02(Consumer<String> consumer){
        consumer.accept("abc");
    }
    @Test
    public void f1(){
        test02(s -> System.out.println(s.length()));//3
        test02(s -> System.out.println(s.toUpperCase()));//ABC
    }
}

生产者 supplier

import java.util.function.Supplier;

public class supplier {
    public User test01(java.util.function.Supplier<User> supplier){
        return  supplier.get();
    }
    @Test
    public void f1(){
        User user = test01(() -> new User(1,"张三",18));
        User user2 = test01(() -> new User(2,"李四",19));
        System.out.println(user);
        System.out.println(user2);

    }
}

断言 predicate

import org.junit.Test;

import java.util.function.Predicate;

public class predicate {
    public boolean test02(Predicate<String> predicate){
        return predicate.test("abc");
    }


    @Test
    public void f1(){
        test02(new Predicate<String>() {
            @Override
            public boolean test(String s) {
                return s.contains("a");
            }
        });

        System.out.println(test02(s -> s.contains("a"))); //true
        System.out.println(test02(s -> s.length() == 5));// false
    }

}

转换 function

import org.junit.Test;

import java.util.function.Function;

public class function {
    public Person test01(Function<String,Person> function){
        return function.apply("宋宋");
    }

    @Test
    public void f1(){
        System.out.println(test01(s -> new Person(s)));
    }
}

实体类 User

public class User {
    private int id;
    private String name;
    private int age;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    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() {
    }

    public User(int id, String name, int age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

实体类 Person

package com.example.函数式接口;

public class Person {
    private String name;

    public Person(String name) {
        this.name = name;
    }

    public Person() {
    }

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