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我开始发展我的JAVA技能，但是我有一个疑问。 我在JAVA中创建一个对象，创建了构造函数等，然后，它询问“将AGE_RECENT值从1更改为3”，我最初声明这是最终的，因为我从未想过它会改变，所以没有SET或GET已创建。我想知道如何在SET方法中将值从1更改为3。 我有这个变量如何更改SET方法中的值
private static int AGE_RECENT=1;
我做到了。
public void setAgeRecent() {
Vehicle.AGE_RECENT = 3;
}
它可以工作，如果您运行程序，它会更改变量的值，但是没有在每个SET方法中声明该方法。 只是想知道我该如何做到这一点。如果这是正确的，好的，如果没有，谢谢你的帮助！
正如有人问，代码。
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package tp1;
/**
*
* @author Nelson
*/
public class Vehicle {
/** Variáveis da classe, têm como função **/
private String registration;
private int registrationYear;
private double consumption;
private double autonomy;
private int cilinderCapacity;
/**
* Final variables. They are final because they do not suffer any kind of modification during the project.
* YEAR_OMISSION is 2016 because the currect year is 2016.
* ENVIRONMENTAL_CHARGE_OMISSION is 0.10(10 cents), gave this value because there is nothing to mention the
especific value, hence why I gave 0.10.
* RATING_RECENT = Is a string, just has the text "RECENT" inside.
* RATING_COMTEMPORY - Another string, just with the "Comtempory" text inside.
* RATING_CLASSIC - Yet again another string, with the "Classic" text.
* AGE_RECENT - It is to help to compare if a vehicle is recent or not, it has the value 3.
* AGE_CLASSIC - It is to again help to compare, value is 20.
*/
private static final int YEAR_OMISSION = 2016;
private static final double ENVIRONMENTAL_CHARGE_OMISSION=0.10;
private static final String RATING_RECENT="Recent";
private static final String RATING_CONTEMPORY="Contempory";
private static final String RATING_CLASSIC="Classic";
private static int AGE_RECENT=1;
private static final int AGE_CLASSIC=20;
/**
* Constructor of the object, it has the Registration
* @param registration
* @param registrationYear - The year the vehicle was first registered.
* @param consumption - How many liters the vehicle consumes.
* @param autonomy - How many KMs a vehicle can go without refuelling.
* @param cilinderCapacity - How many Cubic Inches the engine has.
*/
public Vehicle(String registration,int registrationYear, double consumption, double autonomy, int cilinderCapacity) {
this.registration = registration;
this.registrationYear = registrationYear;
this.consumption = consumption;
this.autonomy = autonomy;
this.cilinderCapacity = cilinderCapacity;
}
/**
* Null Constructor, it has no values, they will be attributed in the MAIN Class.
*/
public Vehicle() {
this.registration = "";
this.registrationYear = 0;
this.consumption = 0;
this.autonomy = 0;
this.cilinderCapacity =0;
this.registrationYear = YEAR_OMISSION;
}
/**
* Copy Constructor.
*/
public Vehicle(Vehicle vehicle) {
this.registration = vehicle.getRegistration();
this.registrationYear = vehicle.getRegistrationYear();
this.consumption = vehicle.getConsumption();
this.autonomy = vehicle.getAutonomy();
this.cilinderCapacity = vehicle.getCilinderCapacity();
}
public String getRegistration() {
return registration;
}
public int getRegistrationYear() {
return registrationYear;
}
public double getConsumption() {
return consumption;
}
public double getAutonomy() {
return autonomy;
}
public int getCilinderCapacity() {
return cilinderCapacity;
}
public double getYearRecent() {
return AGE_RECENT;
}
public double getAgeRecent(){
return AGE_RECENT;
}
public void setRegistration(String registration) {
this.registration = registration;
}
public void setRegistrationYear(int registrationYear) {
this.registrationYear = registrationYear;
}
public void setConsumption(double consumption) {
this.consumption = consumption;
}
public void setAutonomy(double autonomy) {
this.autonomy = autonomy;
}
public void setCilinderCapacity(int cilinderCapacity) {
this.cilinderCapacity = cilinderCapacity;
}
public void setAgeRecent() {
Vehicle.AGE_RECENT = 3;
}
/**
* Calculate the age of the vehicle to compare in the vehicleRating method
* @return The year, which is 2016 minus the year the vehicle was first registered.
*/
private int calculateAge(){
return YEAR_OMISSION-this.registrationYear;
}
/**
* Calculate the Circulation Tax.
* @return Returns the value of the Environmental Charge multiplied by the Cilinder Capacity of the vehicle.
*/
public double calculateCirculationTax(){
return ENVIRONMENTAL_CHARGE_OMISSION*cilinderCapacity;
}
/**
* Classify the vehicle based on the age.
* If the result given by the calculateAge method is minor than the AGE_RECENT variable(3), then it will
return "Recent"
* If the result is between Age_RECENT and AGE_CLASSIC(20), then it will say "Contemporary"
* If none of the IFs apply, it will return "Classic".
**/
public static String vehicleRating(Vehicle vehicle) {
if(vehicle.calculateAge() < Vehicle.AGE_RECENT) {
return Vehicle.RATING_RECENT; }
else if ((vehicle.calculateAge()>=Vehicle.AGE_RECENT)&&(vehicle.calculateAge()<=Vehicle.AGE_CLASSIC)){
return Vehicle.RATING_CONTEMPORY;}
else
return Vehicle.RATING_CLASSIC;
}
@Override
public String toString() {
return "Vehicle{" + "registration=" + registration + ", registrationYear=" + registrationYear + ", consumption=" + consumption + ", autonomy=" + autonomy + ", cilinderCapacity=" + cilinderCapacity + '}';
}
}
变量不是最终的，是静态的，这意味着它属于类，静态变量和最终变量之间存在巨大差异。 –
它可能会有助于显示其余的代码，以便我们可以看到发生了什么。该属性可能最适合作为实例变量而不是类变量。 –
我知道它不是最终的，它是在一开始，但如果我想改变它，这将是不可能的，因为你知道，我删除了最终。 –