Java中的参数传递

Java中方法参数传递是：值传递(Pass By Value)

public class ParameterDemo{

    public void changeValue1(int a){

        a = 8;

    }

    public void changeValue2(Employee e){

        e.salary = 8000;

    }

    public void changeValue3(Employee e){

        e = new Employee();

        e.salary = 8000;

    }

    public void swap(Employee e, Employee e2){

        Employee temp = e;

        e = e2;

        e2 = temp;

    }

  

    public static void main(String[] args){

        MethodDemo m = new MethodDemo();

         

        int a = 10;

        System.out.println(a);//10

        m.changeValue1(a);

        System.out.println(a);//10

         

        Employee e = new Employee();

        System.out.println(e.salary);//0

        m.changeValue2(e);

        System.out.println(e.salary);//8000

        Employee e2 = new Employee();

        System.out.println(e2.salary);//0

        m.changeValue3(e2);

        System.out.println(e2.salary);//0

        Employee e3 = new Employee();

        e3.name = "huhu";

        Employee e4 = new Employee();

        e4.name = "hengheng";

        System.out.println("e3.name = "+e3.name+" e4.name = "+ e4.name);//e3.name = huhu e4.name = hengheng

        m.swap(e3, e4);

        System.out.println("e3.name = "+e3.name+" e4.name = "+ e4.name);//e3.name = huhu e4.name = hengheng

    }

}

class Employee{

    String name;

    int salary;

}