来自txt文件的ArrayList麻烦

Question

4 类：

1. Party - 一些生物的索引、名称、位置和列表（通过指向 Creature 类实例的链接访问）。
2. Creature - 索引、类型、名称、索引派对、移情值、恐惧值、宝藏清单、文物清单
3. Treasure - 索引、类型、生物按索引、权重、值
4. Artifact - 索引、类型、索引生物、其他字段

使用 ArrayList 类来保存上述类的实例。

测试数据（看起来像）：

p : 10003 : Conglomeration

c : 20001 : Woman   : Lucy   :10001 : 17 : 22 : 20

t : 30004 : Silver : 20005 : 120 : 1000

a : 40001 : Wand : 20007 : ElderWand

这是我到目前为止所写的：

import java.io.IOException;
import java.util.*;
import javax.swing.JFileChooser;
import java.util.Scanner;

public class SorcerersCave {

    public static void main(String[] args) {

        ArrayList<Party> partyList = new ArrayList<Party>();
        ArrayList<Creature> creatureList = new ArrayList<Creature>();
        ArrayList<Treasure> treasureList = new ArrayList<Treasure>();
        ArrayList<Artifact> artifactList = new ArrayList<Artifact>();


            // open and read file:
            try {
                Scanner scanner = new Scanner(chooser.getSelectedFile())
                        .useDelimiter("\\s*:\\s*");

                while (scanner.hasNextLine()) {

                    String line = scanner.nextLine();

                    int index;
                    String type;
                    String name;

                    char identifier = line.charAt(0);

                    if (identifier == 'p') {
                        index = scanner.nextInt();
                        name = scanner.next();
                        partyList.add(new Party(partyInfo(index, name)));

                    } else if (identifier == 'c') {
                        index = scanner.nextInt();
                        type = scanner.next();
                        name = scanner.next();
                        int partyC = scanner.nextInt();
                        int empathyC = scanner.nextInt();
                        double carryingCapacityC = scanner.nextDouble();
                        creatureList.add(new Creature(creatureInfo(index, type,
                                name, partyC, empathyC, carryingCapacityC)));

                    } else if (identifier == 't') {
                        index = scanner.nextInt();
                        type = scanner.next();
                        int creatureT = scanner.nextInt();
                        double weightT = scanner.nextDouble();
                        int valueT = scanner.nextInt();
                        treasureList.add(new Treasure(treasureInfo(index, type,
                                creatureT, weightT, valueT)));

                    } else if (identifier == 'a') {
                        index = scanner.nextInt();
                        type = scanner.next();
                        int creatureA = scanner.nextInt();
                        artifactList.add(new Artifact(artifactInfo(index, type,
                                creatureA)));

                    } else {
                        System.out.println("This is not a valid line of input");
                    }
                    System.out.println("Identifier: " + identifier);
                }

            } catch (IOException e) {
                e.printStackTrace();
            }
            System.out.println("party: " + partyList.toString());
        }
    }

    private class Creature {

    public Creature (int index, String type, String name,
            int partyC, int empathyC, double carryingCapacityC) {
        return;
    }
}
    private class Party {

        public Party(int index, String name) {
            return;
        }
    }

    private class Artifact {

        public Artifact(int index, String type, int creatureA) {
            return;
        }
}
        private class Treasure {
            public Treasure(int index, String type, int creatureT,
                    double weightT, int valueT) {
                return ;
            }

}

我知道我已经遇到了问题，因为当我尝试打印 partyList 数组的内容时。它是空的。我就是不明白为什么。

存在的错误：

Exception in thread "main" java.util.InputMismatchException
at java.util.Scanner.throwFor(Unknown Source)
at java.util.Scanner.next(Unknown Source)
at java.util.Scanner.nextInt(Unknown Source)
at java.util.Scanner.nextInt(Unknown Source)
at SorcerersCave.main(SorcerersCave.java:43)

想法** 我是否有可能拥有 if-else 循环和“查看”相应的类来查看要扫描的内容（而不是在循环中完成所有操作）？例如：如果第一个字母是“p”，就去派对班看看如何处理这条线。

Answer 1

我认为您的问题是您扫描了这些行中的所有输入：

           while (scanner.hasNext())
                    System.out.println(scanner.nextLine());

而且你的课看起来很不寻常。为什么使用static Object？
只需为每种类型构建常规类，例如：

private class Creature{
   // data fields

   public Creature(int index, String type, String name, int partyC, int empathyC, double carryingCapacityC){
      // set data field values
   }

   // accessors, mutators etc.
}

类似这样的： http://goo.gl/hM2Fo

Answer 2

我的建议是，你应该尝试使用调试模式。

PS。主要问题是你试图从无到有创建一个对象。

Answer 3

如果我没看错，你所有的对象都返回 null。然后，您尝试将空引用附加到 arrayList 并且它忽略它。尝试实际制作对象并查看结果。

来自关于 add() 的 Collections javadoc

Collections that support this operation may place limitations on what elements may be 
added to this collection. In particular, some collections will refuse to add null
elements, and others will impose restrictions on the type of elements that may be added.
Collection classes should clearly specify in their documentation any restrictions on what  
elements may be added.