Lambda 函数式编程

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

public interface Cook {
    void makeFood();
}


public class CookLambda {
    public static void main(String[] args) {
        invoke(new Cook() {
            @Override
            public void makeFood() {
                System.out.println("noodles");
            }
        });

        invoke(() -> System.out.println("rices"));
    }

    private static void invoke(Cook cook) {
        cook.makeFood();
    }
}

 

 

 

 

public interface Calculator {
    public abstract int calc(int a , int b);
}
   

public class MinLambdaDemo {
    public static void main(String[] args) {
        invokeCalc(10, 30, new Calculator() {
            @Override
            public int calc(int a, int b) {
                return a + b;
            }
        });

        invokeCalc(15, 28, (a, b) -> a + b);
    }

    private static void invokeCalc(int a, int b, Calculator calculator) {
        int sum = calculator.calc(a, b);
        System.out.println(sum);
    }
}

public class Student {
    private String studentName;
    private int studentAge;

    public String getStudentName() {
        return studentName;
    }

    public void setStudentName(String studentName) {
        this.studentName = studentName;
    }

    public int getStudentAge() {
        return studentAge;
    }

    public void setStudentAge(int studentAge) {
        this.studentAge = studentAge;
    }

    public Student() {
    }

    public Student(String studentName, int studentAge) {
        this.studentName = studentName;
        this.studentAge = studentAge;
    }

    @Override
    public String toString() {
        return "Student{" +
                "studentName='" + studentName + '\'' +
                ", studentAge=" + studentAge +
                '}';
    }
}


public class ArraysSortLambda {
    public static void main(String[] args) {
        Student[] students = {
                new Student("jim", 15),
                new Student("lily", 13),
                new Student("mary", 18)
        };
//        Arrays.sort(students, new Comparator<Student>() {
//            @Override
//            public int compare(Student o1, Student o2) {
//                return o1.getStudentAge() - o2.getStudentAge();
//            }
//        });

        Arrays.sort(students, (o1, o2) -> o2.getStudentAge() - o1.getStudentAge());

//        System.out.println(Arrays.toString(students));
        for (Student student : students) {
            System.out.println(student);
        }
    }
}