Java中参数传递

/*=============================================================================
#     FileName: ParamTest.java
#         Desc:   这个例子说明了在java当中过程参数，就算是传递的是引用，也是按照值传递的方式来进行的
#       Author: BarneyX
#        Email: [e-mail]
#     HomePage:
#      Version: 0.0.1
#   LastChange: 2016-01-04 10:22:16
#      History:
=============================================================================*/
public class ParamTest{
    public static void main(String[] args){


        /**
         *  Test 1:Methods can't modify numeric parameters
         * */
        System.out.println("Testing tripleValue");
        double percent = 10;
        System.out.println("Before: percent="+percent);
        tripleValue(percent);
        System.out.println("After: percent="+percent);


        /**
         *  Test 2:Methods can change the state of object parameter
         * */

        System.out.println("\nTesting tripleSalary:");
        Employee harry = new Employee("Harry",50000);
        System.out.println("Before:salary="+harry.getSalary());
        tripleSalary(harry);
        System.out.println("After:salary="+harry.getSalary());


        /**
         * Test 3:Methods can't attch new objects to object paramets
         * */
        System.out.println("\nTesting swap");
        Employee a = new Employee("Alice",70000);
        Employee b = new Employee("Bob",60000);
        System.out.println("Before:a="+a.getName());
        System.out.println("Before:b="+b.getName());
        swap(a,b);
        System.out.println("After:a="+a.getName());
        System.out.println("After:a="+a.getName());

    }

    public static void tripleValue(double x){
        x= 3*x;
        System.out.println("End of method: x="+x);
    }

    public static void tripleSalary(Employee x){
        x.raiseSalary(200);
        System.out.println("End of method: salary="+x.getSalary());
    }

    public static void swap(Employee x,Employee y){
        Employee temp = x;
        x= y;
        y = temp;
        System.out.println("End of method: x="+x.getName());
        System.out.println("End of method: x="+y.getName());
    }

}


class Employee{
        private String name;
        private double salary;


        public Employee(String n,double s){
            name = n;
            salary = s;
        }

        public String getName(){
            return name;
        }

        public double getSalary(){
            return salary;
        }

        public void raiseSalary(double byPercent){
            double raise = salary * byPercent / 100;
            salary +=raise;
        }
}
/*************************************************
 C:\Windows\system32\cmd.exe /c (java ParamTest)
Testing tripleValue
Before: percent=10.0
End of method: x=30.0
After: percent=10.0

Testing tripleSalary:
Before:salary=50000.0
End of method: salary=150000.0
After:salary=150000.0

Testing swap
Before:a=Alice
Before:b=Bob
End of method: x=Bob
End of method: x=Alice
After:a=Alice
After:a=Alice
Hit any key to close this window...
**************************************************/