如何在java中格式化输出控制台列？

我制作了一个创建发票的程序，但是当它涉及到数千个数字时，输出并不整洁，并且破坏了一切。我如何解决这个问题，使程序的列与这样的数字更加对齐？这是我用来创建程序的代码。如果有人能帮忙，那就太好了

这是一个主要的方法

public class InvoicePrinter
{
public static void main(String[] args)
  {

  Address samsAddress=new Address("Sam's Small Appliances", "100 Main 
  Street", "Anytown", "CA", "98765");
  Invoice samsInvoice =new Invoice(samsAddress);
  samsInvoice.add(new Product("Toaster", 29.95),3);
  samsInvoice.add(new Product("Hair Dryer", 24.95),1);      
  samsInvoice.add(new Product("Car Vacuum",19.99),2);
  samsInvoice.add(new Product("Nano Parts",100000),1);
  samsInvoice.addSimple(new Product("Shipping",5.00));

  System.out.println(samsInvoice.format());
  }
}

这些是该计划运行所需的其他计划

import java.util.ArrayList;

public class Invoice
{
  public Invoice(Address anAddress)
  {
  items=new ArrayList<LineItem>();
  billingAddress=anAddress;
  simpleItems= new ArrayList<SimpleLineItem>();
}

public void addSimple(Product aProduct)
{
  SimpleLineItem anItem= new SimpleLineItem(aProduct);
  simpleItems.add(anItem);
}


public void add(Product aProduct, int quantity)
{
  LineItem anItem=new LineItem(aProduct,quantity);
  items.add(anItem);
}   

 public String format()
 {
  String r="                                                 I N V O I C E\n\n"+billingAddress.format()+String.format("\n\n%-30s%8s%5s%8s\n","Description", "Price","Qty","Total");

  for(LineItem i:items)
  {
     r=r+i.format()+"\n";
  }

  for(SimpleLineItem j:simpleItems)
  {
   r=r+j.format() + "\n";
  }

  r = r + String.format("\nAMOUNT DUE: $%8.2f", getAmountDue());
  return r;
  }

 public double getAmountDue()
 {
  double amountDue = 0;
  for (LineItem i : items)
  {
      amountDue = amountDue + i.getTotalPrice();
  }
  for(SimpleLineItem j:simpleItems)
  {
     amountDue = amountDue + j.getPrice();
  }
 return amountDue; 
  }     


 private Address billingAddress;
 private ArrayList<LineItem> items;
 private ArrayList<SimpleLineItem> simpleItems;
}

另一个

public class SimpleLineItem
{
  public SimpleLineItem(Product aProduct)
  {
     theProduct=aProduct;
  }

  public double getPrice()
  {
     return theProduct.getPrice();   
  }

  public String format()
  {
    return String.format("%-30s" +"             " + "%8.2f",
    theProduct.getDescription(), theProduct.getPrice());
  }

  private Product theProduct;
  }  

再来两个

  public class Product
  {  
   public Product(String aDescription,double aPrice)
   {
     description = aDescription;
     price = aPrice;
   }

   public String getDescription()
   {
     return description;
   }

   public double getPrice()
   {
     return price;
   }

   private String description;
   private double price;
   }

最后一个

   public class Address
   {
     public Address(String aName, String aStreet, String aCity, String 
     aState,String aZip)
    {
       name = aName;
       street = aStreet;
       city = aCity;
       state = aState;
       zip = aZip;
    }

   public String format()
   {
     return name + "\n" + street + "\n" + city + ", " + state + " " + zip;
   }

   private String name;
   private String street;
   private String city;
   private String state;
   private String zip;
  }

---

因此，基本上，在打印出所有内容之前，无法确定数字列的总长度时，就会发生这种情况。为此，您需要将数字列的长度设置为最长的数字，或者在您的情况下设置为price length，并正确证明所有数字。因此，您需要将所有数字添加到一个数组中，并通过循环找到最长的数字

也许您可以在System.out.format和DecimalFormat类上查看Oracle的javadocs

---

我试图运行您的代码，并在线程“main”java.util.UnknownFormatConversionException:Conversion=''中抛出一个异常：异常，与int数组类似？我该怎么做呢？不，你使用价格，所以把它们放到一个双数组中。在打印整个表之前，循环遍历此数组并获取数字的最大字符长度。为列值创建必要的缩进

   public class Address
   {
     public Address(String aName, String aStreet, String aCity, String 
     aState,String aZip)
    {
       name = aName;
       street = aStreet;
       city = aCity;
       state = aState;
       zip = aZip;
    }

   public String format()
   {
     return name + "\n" + street + "\n" + city + ", " + state + " " + zip;
   }

   private String name;
   private String street;
   private String city;
   private String state;
   private String zip;
  }