所以我整个下午一直在看这段代码而且我看不到错误。这是我应该做的：
为送达服务创建Delivery课程。该类包含用于保存以下内容的字段：
为接受年份参数的Delivery类创建构造函数，
年内交货编号，交货距离代码和包裹重量。该
构造函数确定八位数的交货编号和交货费用。还包括一个
显示每个Delivery对象字段的方法。将文件另存为Delivery.java。
接下来，创建一个应用程序，提示用户输入数据。保持 提示用户输入以下每个值，直到它们有效：
当所有数据条目都有效时，构造一个Delivery对象，然后显示它
值。将文件另存为CreateDelivery.java。
所以这是我的送货类
import javax.swing.*;
import java.util.*;
class Delivery
{
//variables
private int year;
private int deliveryNumber; //deliveryNo
private double weight;
private int distanceCode; //code
//constructor
//Delivery()
//{
// year = year;
// deliveryNumber = deliveryNumber;
// weight = weight;
// distanceCode = distanceCode;
//}
//get year
public int getYear()
{
return year;
}
//set year
public int setYear (int newYear)
{
year = newYear;
return year;
}
//get deliveryNumber
public int getDeliveryNumber()
{
return deliveryNumber;
}
//set deliveryNumber
public int setDeliveryNumber (int newDeliveryNumber)
{
deliveryNumber = newDeliveryNumber;
return deliveryNumber;
}
//get weight
public double getWeight()
{
return weight;
}
//set Weight
public double setWeight (double newWeight)
{
weight = newWeight;
return weight;
}
//get distanceCode
public int getDistanceCode()
{
return distanceCode;
}
//set distanceCode
public int setDistanceCode (int newDistanceCode)
{
distanceCode = newDistanceCode;
return distanceCode;
}
//calculate fee
public double displayFees(int distance, double w) //distance = c
{
double fees = 0;
if(distance == 1)
{
if(w < 5)
{
fees = 12;
}
else if((w < 20)&&(w > 5))
{
fees = 16.50;
}
else if(w > 20)
{
fees = 22;
}
}
else if(distance == 2)
{
if(w < 5)
{
fees = 35;
}
else if(w >= 5)
{
fees = 47.95;
}
}
return fees;
}
//display method
public void display(int year, int deliveryNumber, double weight, int distanceCode)
{
System.out.println("Year: " + year + '\n'
+ "Delivery Number: " + deliveryNumber + '\n'
+ "Weight of the package: " + weight + '\n'
+ "Delivery code: " + distanceCode);
}
}
这是我的CreateDelivery Class
import javax.swing.JOptionPane;
import java.util.Scanner;
public class CreateDelivery
{
public static void main(String []args)
{
Delivery delivery1 = new Delivery();
//scanner year
Scanner input = new Scanner(System.in);
System.out.print("Please enter the current year, format (yyyy) >>> ");
delivery1.setYear(input.nextInt());
//loop year
while((delivery1.getYear() <= 2000)||(delivery1.getYear() >= 2026))
{
System.out.println('\n'+ "Error, year should be in the range of (2010 - 2025). Please enter a valid option >> ");
delivery1.setYear(input.nextInt());
}
//scanner for delivery number
System.out.print('\n'+ "Please enter a delivery number: ");
delivery1.setDeliveryNumber(input.nextInt());
//loop for delivery number
while((delivery1.getDeliveryNumber() <= 0001)||(delivery1.getDeliveryNumber() >= 10000))
{
System.out.println("Error, the delivery number is a 4 digit number between 0001 and 9999, please enter a valid option >> ");
delivery1.setDeliveryNumber(input.nextInt());
}
//scanner for weight
System.out.print("Please enter the weight of the package (in pounds): ");
delivery1.setWeight(input.nextDouble());
//loop for weight
while((delivery1.getWeight() <= .09)||(delivery1.getWeight() >= 101))
{
System.out.println("Error, the minimum allowed weight is 0.10 pounds and the maximum is 100 pounds. Please enter a valid weight >> ");
delivery1.setWeight(input.nextDouble());
}
//scanner for delivery code
System.out.print("Please enter 1 for local or 2 for long distance deliveries >> ");
delivery1.setDistanceCode(input.nextInt());
//loop for delivery code
while((delivery1.getDistanceCode() == 1) && (delivery1.getDistanceCode() == 2))
{
System.out.println("Error, please enter a valid distance code (1 for local deliveries and 2 for long distance deliveries) >> ");
delivery1.setDistanceCode(input.nextInt());
}
//turn int to string
String n = Integer.toString(delivery1.getDeliveryNumber());
String y = Integer.toString(delivery1.getYear());
String trackingNumber = n + y;
System.out.println(delivery1.getDistanceCode() + " "
+ trackingNumber + " " + delivery1.getWeight() + " " + fees);
}
}
所以我做了你们建议的改动，但现在我不能从Delivery课程中提取费用。有什么想法吗？
答案 0 :(得分：1)
Delivery()
{
year = year;
deliveryNumber = deliveryNumber;
weight = weight;
distanceCode = distanceCode;
}
将其替换为以下内容：
Delivery(int year, int deliveryNumber, int weight, int distanceCode)
{
this.year = year;
this.deliveryNumber = deliveryNumber;
this.weight = weight;
this.distanceCode = distanceCode;
}
从那里，我会避免使用set方法。而是在从System.in加载时将所有值存储到相应的字段中。获得所有字段后，创建Delivery对象。
答案 1 :(得分：1)
我认为您在while循环中的()，getDeliveryNumber等方法的末尾缺少getYear。
并且您还在最后使用未声明的变量，例如getDeliveryNumber，getYear等。
答案 2 :(得分：0)
或者我们可以像交付课程一样做到这一点
public class Delivery {
private int year,deliveryNumber,distanceCode;
private double weight;
private double fees=0;
//delivery class constructor
public Delivery(int year,int deliveryNumber,int distanceCode,double weight)
{
this.year=year;
this.deliveryNumber=deliveryNumber;
this.distanceCode=distanceCode;
this.weight=weight;
}
//calculate delivery fee
public void displayFees(int distanceCode, double weight)
{
if(distanceCode == 1)
{
if(weight<5)
{
fees = 12;
}
else if((weight < 20)&&(weight >=5))
{
fees = 16.50;
}
else if(weight > 20)
{
fees = 22;
}
}
else if(distanceCode == 2)
{
if(weight <5)
{
fees = 35;
}
else if(weight >= 5)
{
fees = 47.95;
}
}
}
public double getFee()
{
return fees;
}
}
和 CreateDelivery 类：
public class CreateDelivery {
public static void main(String[] args) {
int year=(int)ReadValues.readValue("Year", 1999,2026);
int deliveryNumber=(int)ReadValues.readValue("Delivery Number (1 to 10000)", 0,10000);
int distanceCode=(int)ReadValues.readValue("DistanceCode (1 or 2)",0, 3);
double weight=ReadValues.readValue("weight",0, 20);
Delivery delivery=new Delivery(year, deliveryNumber, distanceCode, weight);
delivery.displayFees(distanceCode, weight);
double fee=delivery.getFee();
System.out.println("\n\n*****Delivery Fees Details*****\n\nTrackingNumber:"+year+deliveryNumber+"\nDistanceCode:"+distanceCode+"\nFee :"+fee);
}
}
为了从用户读取值，另一个名为 ReadValue 的类
import java.util.Scanner;
公共类读取值{
public static double readValue(String prompt, int min, int max) {
Scanner scan = new Scanner(System.in);
double value;
System.out.print(prompt + " :");
while (true) {
value = scan.nextDouble();
if (value < min || value > max)
System.out.println("Enter value between " + min + " & " + max);
else
break;
}
return value;
}
}