当用户尝试购买比可用商品更多的商品时,我正在尝试实现OutOfStockException。我不确定我的实现是否正确。您觉得还好吗?
public class OutOfStockException extends Exception {
public OutOfStockException(){
super();
}
public OutOfStockException(String s){
super(s);
}
}
这是我需要测试的课程:
import javax.swing.JOptionPane;
public class SwimItems {
static final int MAX = 100;
public static void main (String [] args)
{
Item [] items = new Item[MAX];
int numItems;
numItems = fillFreebies(items);
numItems += fillTaxable(items,numItems);
numItems += fillNonTaxable(items,numItems);
sellStuff(items, numItems);
}
private static int num(String which) {
int n = 0;
do {
try{
n=Integer.parseInt(JOptionPane.showInputDialog("Enter number of "+which+" items to add to stock:"));
}
catch(NumberFormatException nfe){
System.out.println("Number Format Exception in num method");
}
} while (n < 1 || n > MAX/3);
return n;
}
private static int fillFreebies(Item [] list)
{
int n = num("FREEBIES");
for (int i = 0; i < n; i++)
try{
list [i] = new Item(JOptionPane.showInputDialog("What freebie item will you give away?"),
Integer.parseInt(JOptionPane.showInputDialog("How many do you have?")));
}
catch(NumberFormatException nfe){
System.out.println("Number Format Exception in fillFreebies method");
}
catch(ArrayIndexOutOfBoundsException e){
System.out.println("Array Index Out Of Bounds Exception in fillFreebies method");
}
return n;
}
private static int fillTaxable(Item [] list, int number)
{
int n = num("Taxable Items");
for (int i = number ; i < n + number; i++)
try{
list [i] = new TaxableItem(JOptionPane.showInputDialog("What taxable item will you sell?"),
Double.parseDouble(JOptionPane.showInputDialog("How much will you charge (not including tax) for each?")),
Integer.parseInt(JOptionPane.showInputDialog("How many do you have?")));
}
catch(NumberFormatException nfe){
System.out.println("Number Format Exception in fillTaxable method");
}
catch(ArrayIndexOutOfBoundsException e){
System.out.println("Array Index Out Of Bounds Exception in fillTaxable method");
}
return n;
}
private static int fillNonTaxable(Item [] list, int number)
{
int n = num("Non-Taxable Items");
for (int i = number ; i < n + number; i++)
try{
list [i] = new SaleItem(JOptionPane.showInputDialog("What non-taxable item will you sell?"),
Double.parseDouble(JOptionPane.showInputDialog("How much will you charge for each?")),
Integer.parseInt(JOptionPane.showInputDialog("How many do you have?")));
}
catch(NumberFormatException nfe){
System.out.println("Number Format Exception in fillNonTaxable method");
}
catch(ArrayIndexOutOfBoundsException e){
System.out.println("Array Index Out Of Bounds Exception in fillNonTaxable method");
}
return n;
}
private static String listEm(Item [] all, int n, boolean numInc)
{
String list = "Items: ";
for (int i = 0; i < n; i++)
{
try{
list += "\n"+ (i+1)+". "+all[i].toString() ;
if (all[i] instanceof SaleItem) list += " (taxable) ";
if (numInc) list += " (Number in Stock: "+all[i].getNum()+")";
}
catch(ArrayIndexOutOfBoundsException e){
System.out.println("Array Index Out Of Bounds Exception in listEm method");
}
catch(NullPointerException npe){
System.out.println("Null Pointer Exception in listEm method");
}
}
return list;
}
private static void sellStuff (Item [] list, int n) {
int choice;
do {
try{
choice = Integer.parseInt(JOptionPane.showInputDialog("Enter item of choice: "+listEm(list, n, false)));
}
catch(NumberFormatException nfe){
System.out.println("Number Format Exception in sellStuff method");
}
}while (JOptionPane.showConfirmDialog(null, "Another customer?")==JOptionPane.YES_OPTION);
JOptionPane.showMessageDialog(null, "Remaining "+listEm(list, n, true));
}
}
最佳答案
实现看起来不错;您不必在异常类中做很多事情。您可能会考虑添加成员,以了解发出请求时缺货的情况,所请求的数量以及有多少库存,以便捕获异常的代码可以访问该信息。例如,这里有一个库存项目代码:
public class OutOfStockException extends Exception {
private int stockCode;
public OutOfStockException(int stockCode){
super();
this.stockCode = stockCode;
}
public OutOfStockException(String s){
super(s);
this.stockCode = stockCode;
}
public int getStockCode() {
return this.stockCode;
}
}
然后,您可以像这样创建一个:
throw new OutOfStockException(StockCodes.WIDGET, "Out of widgets");
但这取决于您,到那时,它就像其他任何东西一样只是类设计。
很多时候,通过这些事情,我只将构造器包括在各个部分中,然后让类本身为基础
Exception
getMessage
消息生成消息。所以:public class OutOfStockException extends Exception {
private int stockCode;
public OutOfStockException(int stockCode){
super("Out of " + StockCodes.getDescription(stockCode));
this.stockCode = stockCode;
}
public int getStockCode() {
return this.stockCode;
}
}
// Throwing one:
throw new OutOfStockException(StockCodes.WIDGETS);
但同样,那只是类设计。
撇开所有这些,这是有点题外话,但在我看来,一件商品缺货是正常现象,不是一个例外。您确定例外确实是正确的建模方法吗?
关于java - Java实现异常处理,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/2488109/