函数式接口示例

FunctionalInterface.java

package org.example;

/**
 * @author claws
 * @since 2023/5/7
 */
public class InterfaceTester {
    public static void main(String[] args) {
        Printer printer = new Printer();
        Person claws = new Person("claws");
        printer.printHelloMsg(claws::sayHello);
    }
}

interface HelloSayer {
    String sayHello();
}

class Person {
    String name;

    Person(String name) {
        this.name = name;
    }
    String sayHello() {
        return "你好！";
    }

    String introduce() {
        return "我是 " + name;
    }
}

class Printer {
    void printHelloMsg(HelloSayer helloSayer) {
        String s = helloSayer.sayHello();
        System.out.println(s);
    }
}