Java 中的 setter 问题 - Internet Bill Program

Question

您好，我在尝试创建的对象中赋值时遇到一些问题，它调用的是我最初设置的变量，而不是我使用 setter 方法设置的变量，奇怪的是它似乎正确地通过了第一个扫描仪，因为我的数学方法工作正常，代码如下：

主要

package a2.internetbill;
import java.util.Scanner;

public class A2InternetBill {

/**
 * @param args the command line arguments
 */
public static void main(String[] args) {
    String type = "A";
    int nUsage = 0;
    String nAccountName = "Bob";
    // inititates objects
    Packages newPackageA = new Packages(type, nUsage, nAccountName, 0.0);

    Scanner in = new Scanner(System.in);

    //
    System.out.println("Please enter a package type(Must be A, B, C or D):\n\r");
    type = in.nextLine();
    newPackageA.setPackageType(type);

    System.out.println("Please Enter Your Name:\n\r ");

    newPackageA.setAccountName(in.nextLine());

    System.out.println("Please enter how much GB of Data you used: \n\r");

    newPackageA.setUsage(in.nextInt());


    String outPut;
    // do maths and prints formatted toString method
    newPackageA.moneyMath(type, nUsage, nUsage);
    outPut = newPackageA.toString();
    System.out.println(outPut);
    System.out.println(newPackageA.getAccountName() + newPackageA.getUsage() + newPackageA.getPackageType());
    // TODO code application logic here
        // instance variables

}

}

class

    /*
 * Makes internet package for specific user
 */
package a2.internetbill;

/**
 * 4 packages are:
 * PACKAGE A (IGNITE_60): 200GB usage for .99 per month. 
 * Extra usage is .00 per GB.
 * 
    PACKAGE B (IGNITE_30): 125GB usage for .99 per month. 
    * Extra usage is .50 per GB.
    PACKAGE C (INTERNET_5): 25GB usage for .99 per month. 
    * Extra usage is  per GB.

    PACKAGE D (UNLIMITED_USAGE): For .99 per month 
    * unlimited access is provided.

 * @author sav
 */


    public class Packages {
    private String packageType;
    private int usage;
    private String accountName;
    public double runningTotal;


    //initiates a Packages object
    public Packages(String type, int nUsage, String nAccountName, double nRunningTotal){
        packageType = type;
        usage = nUsage;
        accountName = nAccountName;
        runningTotal = nRunningTotal;

    }


    // getters
    public String getPackageType(){
        return packageType;
    }

    public int getUsage(){
        return usage;
    }

    public String getAccountName(){
        return accountName;
    }

    // setters     
    public void setPackageType(String type){
        type = packageType;
    }
    public void setUsage(int nUsage){
        nUsage = usage;

    }
    public void setAccountName(String nAccountName){
        nAccountName = accountName;
    }     

    public void moneyMath(String type, int nUsage, double nRunningTotal){
        if (type.equals("A")){
            if (nUsage>=200){
                nRunningTotal = ((nUsage - 200) * 3) + 49.99;
                type = "Ignite_60";
                packageType = type;

            }
            else{
                nRunningTotal = 49.99;
                type = "Ignite_60";
                packageType = type;
            }
        }
        else if (type.equals("B")){
            if (nUsage>=125){
                nRunningTotal = ((nUsage - 125) * 1.5) + 39.99;
                type = "Ignite_30";
                packageType = type;
            }
            else{
                nRunningTotal = 39.99;
                type = "Ignite_30";
                packageType = type;
            }
        }
        else if (type.equals("C")){
            if (nUsage>=25){
                nRunningTotal = ((nUsage - 25) * 5) + 24.99;
                type = "Internet_5";
                packageType = type;
            }
            else{
                nRunningTotal = 24.99;
                type = "Internet_5";
                packageType = type;
            }
        }
        else if (type.equals("D")){
            nRunningTotal = 69.99;
            type = "Unlimited_Usage";
            packageType = type;
        }
        else{
            System.out.println("Something something something");
        }



    }

    // 

    /**
     * Modified toString for specified outputs(formatted as assigned)
     * @return
     */
    @Override
    public String toString(){
        return ("Dear, \n\r" + accountName + " \n\r You have selected the : " + packageType + " package, and your current amount due is: $" + runningTotal);

    }
}

请告诉我如何正确使用扫描仪（我认为这就是现在导致问题的原因），非常感谢，

Answer 1

您的二传手不正确。

public void setPackageType(String type){
    type = packageType;
}
public void setUsage(int nUsage){
    nUsage = usage;
}
public void setAccountName(String nAccountName){
    nAccountName = accountName;
}

应该是，

public void setAccountName(String nAccountName){
    accountName = nAccountName;
}   
public void setPackageType(String type){
    packageType = type;
}
public void setUsage(int nUsage){
    usage = nUsage;
}

Java 中的 setter 问题 - Internet Bill Program

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