Java Lambda 表达式

public class Java8Tester {

public static void main(String args[]){

Java8Tester tester = new Java8Tester();

// 类型声明
MathOperation addition = (int a, int b) -> a + b;

// 不用类型声明
MathOperation subtraction = (a, b) -> a - b;

// 大括号中的返回语句
MathOperation multiplication = (int a, int b) -> { return a * b; };

// 没有大括号及返回语句
MathOperation division = (int a, int b) -> a / b;

System.out.println("10 + 5 = " + tester.operate(10, 5, addition));
System.out.println("10 - 5 = " + tester.operate(10, 5, subtraction));
System.out.println("10 x 5 = " + tester.operate(10, 5, multiplication));
System.out.println("10 / 5 = " + tester.operate(10, 5, division));

// 不用括号
GreetingService greetService1 = message ->

System.out.println("Hello " + message);

// 用括号
GreetingService greetService2 = (message) ->

System.out.println("Hello " + message);

greetService1.sayMessage("Runoob");

greetService2.sayMessage("Google");

}

interface MathOperation {

int operation(int a, int b);

}

interface GreetingService {

void sayMessage(String message);

}

private int operate(int a, int b, MathOperation mathOperation){

return mathOperation.operation(a, b);

}

}