Print 2 ArrayLists with specific format

问题

I am trying to format the output of my program, so it looks easily readable by the user. I am not that good at formatting text and I would really welcome your help.

I am trying to print/display(in my JTextArea). I already have a method to display there:

public void display(String... lines){
     for(String line:lines){
          System.out.println(line);
     }
}

Now, I have the 2 ArrayLists that contain some data which was added to them through the use of the program.

itemOrders = new ArrayList<CafeOrders>();
customers = new ArrayList<CafeCustomer>();

The constructors, respectively:

public CafeOrders(String orderID, String itemName, double price){
    super();
    this.orderID = orderID;
    this.itemName = itemName;
    this.price = price;

}

and

public CafeCustomer(int customerID, String customerName){
    super();
    this.customerID = customerID;
    this.customerName = customerName;
    this.orderNo = UUID.randomUUID().toString();

}

I made it in such a way, that orderNo = orderID.
First the customer name is asked, then when he selects from a list of items, each item is added to the CafeOrders ArrayList along with the customer's ID.

I want to create a method that prints those 2 ArrayLists in the specific format, or something similar:

customerName "with id" orderID "has purchased" itemName1    
                                               itemName2    
                                               itemName3
                                               etc...

Any help would be appreciated!

回答1:

EDITED FOR SPECIFIC FORMAT

Adding extra code to @Shiksha Verma to print the customer name and ID only once:

int x = 0;
for(CafeCustomer customer : customers ){
   for(CafeOrders order: itemOrders ){
       if(customer.getOrderNo.equals(order.getOrderId()) ){
           if(x == 0){
               System.out.println(customer.getCustomerName() +"with Id " + 
               customer.getCustomerId()+ "has purchased: "
               +order.getItemName());
               x = 1;
               continue;
           }  
           System.out.printf("%1$40s",order.getItemName());
       }           
   }
   x = 0;
}

回答2:

for(CafeCustomer customer : customers ){
       for(CafeOrders order: itemOrders ){
           if(customer.getOrderNo.equals(order.getOrderId()) ){
               System.out.println(customer.getCustomerName() +"with Id " + 
                customer.getCustomerId() + "has purchased " 
                +order.getItemName());
           }
       }
   }

回答3:

As long as your customer can have multiple orders I would suggest using

Map<CafeCustomer, List<CafeOrder>>

And then what you can do:

public void display(Map<CafeCustomer, List<CafeOrder>> map)
{
     map.forEach( (customer, orderList) -> {
         System.out.println(customer.getCustomerName() + " has purchased:");
         for(CafeOrder order : orderList)
             System.out.println(order.getItemName());
});
}

回答4:

While this code works:

public void displayOrders(){
    for(CafeCustomer customer : customers ){
        for(CafeOrders order: itemOrders ){
            if(customer.getOrderNo().equals(order.getOrderID()) ){
                display(customer.getCustomerID()+"."+customer.getCustomerName() +"with Order ID " + 
                customer.getOrderNo() + " has purchased a " 
                +order.getItemName());
            }
        }
    }
}

I want the customer ID,name and order ID to appear once and then on the right the list of the items. Like I showed in my initial post.
Is it possible? I can't seem to find a way to do it. Like this:

customerID"."customerName "with id" orderID "has purchased" itemName1    
                                                            itemName2    
                                                            itemName3
                                                            etc...

And it appears exactly like this.

回答5:

modify the code like this :

for(CafeCustomer customer : customers ){

 System.out.println(customer.getCustomerName() +"with Id " + 
            customer.getCustomerId()+ "has purchased ::");

   for(CafeOrders order: itemOrders ){
       if(customer.getOrderNo.equals(order.getOrderId()) ){
           System.out.println("\t\t\t\t\t\t\t"+ order.getItemName());
       }
   }

}

来源：https://stackoverflow.com/questions/47653351/print-2-arraylists-with-specific-format