从数据文件中读取来填充的ArrayList [英] Reading from data file to fill ArrayList

问题描述

我有一个抽象类，订单有三个不同的类实现它一切都在程序运行正常，当我硬codeD命令测试它的程序。

I have a program with an abstract class 'Orders' with three different classes implementing it everything in the program runs fine when I tested it with hard coded orders.

下面是抽象类：

public abstract class Order {
protected String location;
protected double price;

public Order(double price, String location){
    this.price = price;
    this.location = location;
}

public abstract double calculateBill();

public String getLocation() {
    return location;
}

public double getPrice() {
    return price;
}

public abstract String printOrder(String format);

}

在这里参考实施的一个类

And here is one of the implementing classes for reference

public class NonProfitOrder extends Order {

public NonProfitOrder(double price, String location) {
    super(price, location);
}

public double calculateBill() {
    return getPrice();
}

public String printOrder(String format){
    String Long = "Non-Profit Order" + "\nLocation: " + getLocation() +  "\nTotal Price: " + getPrice();
    String Short = "Non-Profit Order-Location: " + getLocation() + ", " + "Total Price: " + getPrice();
    if (format.equals("Long")){
        return Long;
    }
    else{
        return Short;
    }
}
}

这是我的测试，到目前为止，我知道这是错的，pretty凌乱，但处之泰然。 Iv'e一直乱搞努力得到的东西的工作，但没有运气。

This is what I have for a tester so far, I know it is wrong and pretty messy, but take it easy. Iv'e been messing around trying to get something to work, but no luck.

public static ArrayList<Order> readOrders (String fileName) throws FileNotFoundException{
    String type;
    Scanner s = new Scanner(new File("orders.txt"));
    ArrayList<Order> orders = new ArrayList<Order>();
    while (s.hasNext()){
        type = s.nextLine();
    }
    switch(type) {
        case 1: type = NonProfitOrder();
            break;
        case 2: type = RegularOrder();
            break;
        case 3: type = OverseasOrder();
    return orders;
}

}

数据文件，我需要从这个样子的阅读：

The data file I need to read from looks like this:

N 1000.0 NY
R 2000.0 CA 0.09
R 500.0 GA 0.07
N 2000.0 WY
O 3000.0 Japan 0.11 20.0
N 555.50 CA
O 3300.0 Ecuador 0.03 30.0
R 600.0 NC 0.06

首先我无法读取该文件，我知道我需要一个循环，将数据添加到ArrayList，但我不知道怎么样。什么是一个方法来读取和环路所有的最简单的方法？如果可能的话。

First off I am having trouble reading the file, I know i need a loop to add the data to the arrayList, but I'm not sure how . What would be the easiest way to read and loop all in one method? If possible.

我更新了几分添加一个switch语句，我有，不工作的。相反情况下，1,2,3，你会不会反而需要使用一些与N，O，R投其所好与文件
而我无法修复错误类型不匹配。

I updated to add the somewhat of a switch statement that I have, that doesn't work. Instead of case 1,2,3, would I instead need to use something with N, O, R to match up with the file and I'm having trouble fixing the error "type mismatch".

推荐答案

的扫描仪提供了一种简便的方式，通过文件来走。 。接下来（）.hasNext（）.nextLine（）.hasNextLine（）是你的情况是非常有用的方法。

Scanner provides an easy way to walk through the file. .next() .hasNext() .nextLine() .hasNextLine() are very useful methods in your case.

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