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问Java编程项目
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Stack Overflow用户

提问于 2020-03-05 11:08:29

回答 1查看 179关注 0票数 0

我正在从事一个大学项目，任务是使用扫描仪读取多个数据文件的适当数据。该项目涉及一个超类和几个子类。到目前为止，下面的方法工作得很好，并读取与一个名为Tool的类及其所有字段相对应的数据。但是，我最近添加了一个子类ElectricTool，它扩展了类Tool，还引入了两个新字段，它们需要以与前面相同的方式读取，但使用下面所示的相同方法。我试过很多东西，但我似乎想不出来。有什么建议吗？最好是尽可能的干净/简单的代码，我认为它需要一个读的声明，但我正在挣扎。方法如下：

public void readToolData()

{
    Frame myFrame = null;
    FileDialog fileBox = new FileDialog(myFrame,"Open", FileDialog.LOAD);
    fileBox.setVisible(true);
    String directoryPath = fileBox.getDirectory();
    String fileName = fileBox.getFile();

    File dataFile = new File(fileName);
    System.out.println(fileName +"  "+ directoryPath);
    Scanner scanner = null;
    try
    {
        scanner = new Scanner(dataFile);
    }
    catch (FileNotFoundException e)
    {
        System.out.println(e);
    }

    while( scanner.hasNextLine() )
    {
        String lineOfText = scanner.nextLine().trim().replaceAll("\\s+","");
        if(!lineOfText.isEmpty() && !lineOfText.matches("^//.*") && !lineOfText.substring(0,1).equals("["))
        {
            System.out.println(lineOfText);      
        }
        else{
            continue;
        }

        Scanner scanner2 = new Scanner(lineOfText).useDelimiter("\\s*,\\s*");
        while(scanner2.hasNext())
        {
            Tool tool = new Tool();
            tool.readData(scanner2);


            storeToolList(tool);
        }

    }
    scanner.close();
}

电动工具类

工具类

数据文件

java

subclass

回答 1

Stack Overflow用户

回答已采纳

发布于 2020-03-05 11:52:59

  public void readToolData() {
    Frame myFrame = null
    FileDialog fileBox = new FileDialog(myFrame, "Open", FileDialog.LOAD);
    fileBox.setVisible(true);
    String directoryPath = fileBox.getDirectory();
    String fileName = fileBox.getFile();

    File dataFile = new File(directoryPath + fileName);
    System.out.println(fileName + "  " + directoryPath);
    Scanner scanner = null;
    try {
      scanner = new Scanner(dataFile);
    } catch (FileNotFoundException e) {
      System.out.println(e);
    }

    // Current tool type
    String toolType = null;
    while( scanner.hasNextLine() ) {
      String lineOfText = scanner.nextLine().trim();

      // Skip empty lines and commentaries
      if(lineOfText.isEmpty() || lineOfText.startsWith("//")) {
        continue;
      }

      if (lineOfText.startsWith("[")) {
        // Extract the tool type name
        String withoutBracket = lineOfText.substring(1);
        // Split by spaces and take the first word
        String[] words = withoutBracket.split(" ");
        toolType = words[0];
        System.out.println("Reading information about " + toolType);
        continue;
      }

      System.out.println(lineOfText);

      Scanner scanner2 = new Scanner(lineOfText).useDelimiter("\\s*,\\s*");
      Tool tool = null;
      if ("ElectricTool".equals(toolType)) {
        tool = new ElectricTool();
      }
      // In the future here will come more cases for different types, e.g.:
      // else if ("HandTool".equals(toolType)) {
      //    tool = new HandTool();
      // }
      if (tool != null) {
        tool.readData(scanner2);
        storeToolList(tool);
      }
    }
    scanner.close();
  }

删除scanner.skip行中的Tool.readData：

public class Tool {

  public void readData(Scanner scanner) {
   toolName = scanner.next(); 
   itemCode = scanner.next(); 
   timesBorrowed = scanner.nextInt(); 
   onLoan = scanner.nextBoolean(); 
   cost = scanner.nextInt(); 
   weight = scanner.nextInt(); 
   scanner.skip(".*");   // Remove this line  
  }

}

并在readTool中实现ElectricTool方法：

 @Override
 public void readData(Scanner scanner) {
   super.readData(scanner);
   rechargeable = scanner.nextBoolean();
   power = scanner.next(); // Or nextInt? what is the type of power field?
 }

若要打印有关应使用多态性的工具的信息，请执行以下操作。在printAllTools中修改Shop.java方法如下：

public void printAllTools() {
  System.out.println("Information");
  System.out.println("---------->");
  for (Tool t : toolList) {
    System.out.println("You have selected:\n");
    t.printDetails();
  }
}

现在，您在Tool.java中的方法Tool.java必须如下所示：

public void printDetails() {
  System.out.println("Tool name: " + toolName + "\n" +
    "Item code: " + itemCode + "\n" +
    "Times borrowed: " + timesBorrowed + "\n" +
    "On load: " + onLoan + "\n" + 
    "Cost: " + cost + "\n" +
    "Weight: " + weight + "g\n"
  );
}

在ElectricTool.java中：

public void printDetails() {
  super.printDetails();
  System.out.println("Rechargeable: " + rechargeable + "\n" +
   "Power: " + power + "\n"
  );
}

票数 1

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/60544007

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