Java中传递参数

J一般语言例如C++，都支持按值传递和引用传递。而在Java中支持按值传递，也就是所说的对象引用，下面是对其传递参数的示例。

package com.company;


public class Main {

    public static void main(String[] args) {
   // write your code here
        //Test 1
        System.out.println("Testing triplevalue:");
        double percent=10;
        System.out.println("Before:percent="+percent);
        triplevalue(percent);
        System.out.println("After:percent="+percent);

        //Test 2
        System.out.println("\nTesting triplesalary:");
        Employee harry=new Employee("Harry",50000);
        System.out.println("Before:salary:"+harry.getSalary());
        triplevalue(harry);
        System.out.println("After:salary"+harry.getSalary());

        //Test 3
        System.out.println("\nTesting swap:");
        Employee a=new Employee("Alice",7000);
        Employee b=new Employee("Bob",8000);
        System.out.println("Before:a="+a.getSalary());
        System.out.println("Before:b="+b.getSalary());
        swap(a,b);
        System.out.println("After:a="+a.getName());
        System.out.println("After:b="+b.getName());
    }

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

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

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

运行结果：

Testing triplevalue:
Before:percent=10.0
End of method:x=30.0
After:percent=10.0


Testing triplesalary:
Before:salary:50000.0
End of the method:Salary=150000.0
After:salary150000.0


Testing swap:
Before:a=7000.0
Before:b=8000.0
End of the method:x=Bob
End of the method:y=Alice
After:a=Alice
After:b=Bob

由此知道Java中的对象引用传递参数。