Question

    String nameFromFile;
    String colorFromFile;
    int capacityFromFile;
    int currentCountFromFile;


    while(inputFile.hasNextLine()){
        nameFromFile = inputFile.next();
        colorFromFile = inputFile.next();
        capacityFromFile = inputFile.nextInt();
        currentCountFromFile = inputFile.nextInt();

        MarbleSackOwner owner1 = new MarbleSackOwner(nameFromFile, colorFromFile,
                                    capacityFromFile, currentCountFromFile);


        nameFromFile = inputFile.next();
        colorFromFile = inputFile.next();
        capacityFromFile = inputFile.nextInt();
        currentCountFromFile = inputFile.nextInt();

        MarbleSackOwner owner2 = new MarbleSackOwner(nameFromFile, colorFromFile,
                                    capacityFromFile, currentCountFromFile);

        nameFromFile = inputFile.next();
        colorFromFile = inputFile.next();
        capacityFromFile = inputFile.nextInt();
        currentCountFromFile = inputFile.nextInt();

        MarbleSackOwner owner3 = new MarbleSackOwner(nameFromFile, colorFromFile,
                                    capacityFromFile, currentCountFromFile);

        nameFromFile = inputFile.next();
        colorFromFile = inputFile.next();
        capacityFromFile = inputFile.nextInt();
        currentCountFromFile = inputFile.nextInt();

        MarbleSackOwner owner4 = new MarbleSackOwner(nameFromFile, colorFromFile,
                                    capacityFromFile, currentCountFromFile);

    }
    String output = "Owners after creaton based on file read \n";
    output += "Owner1: " + owner1 + "\n";
    output += "Owner2: " + owner2 + "\n";
    output += "Owner3: " + owner3 + "\n";
    output += "Owner4: " + owner4 + "\n";

    output += "owner1's name is " + owner1.getName() + "\n";
    output += "like I said, owner1 has " + owner1.howManyMarbles() + 
                " marbles in his sack.\n";
    output += "So lets take one away from him.\n";
    owner1.removeMarbles(1);
    output += "so now we see that he has " + owner1.howManyMarbles() +
                " in his sack.\n";
    output += "so lets give the darn thing back to him now.\n";
    owner1.addMarbles(1);
    output += "so now we see that he has " + owner1.howManyMarbles() +
                " in his sack.\n";

    //mess with owner4
    output += "so, maybe " + owner4.getName() +
                " has lost a marble or two, so lets give him back one.\n";
    owner4.addMarbles(1);
    output += "So now we see that he has " + owner4.howManyMarbles() + 
                " marbles in his sack.\n\n";

    //test class method
    output += "the owner with the most marbles is " +
                bigOwner(owner1, owner2, owner3, owner4);

    //results
    JOptionPane.showMessageDialog(null, output, TITLE_BAR, JOptionPane.INFORMATION_MESSAGE);

}//main

我在while循环之外的每个对所有者对象的调用中遇到错误，说＆＃34;所有者＃无法解析为变量＆＃34;。如果我在循环之前声明对象，我会在循环中创建的对象上出现重复的对象错误。我不太确定如何使这项工作。

Answer 1

您已在while循环内同时声明并初始化变量owner1，owner2，owner3。您可以做的是，首先在（外部）循环之前声明并初始化变量，并在while循环中创建所有者对象，如下所示：

csv.reader

同样对其他两个所有者变量执行此操作。阅读变量范围以便更好地理解。

http://www.java-made-easy.com/variable-scope.html

如果要创建多个所有者对象，则可以在while循环上方创建一个列表对象，并将所有者对象添加到该列表中，并在打印值时从列表中检索添加的对象。

Answer 2

如果要在while和while中访问这些变量，则需要在外部声明它们。在您的情况下，这些变量只在while内部知道，因为它们已经被声明。尝试阅读可变范围。

尝试这样的事情：

MarbleSackOwner owner1 = new MarbleSackOwner(string.Empty, string.Empty, 0, 0),
owner2 = new MarbleSackOwner(string.Empty, string.Empty, 0, 0),
owner3 = new MarbleSackOwner(string.Empty, string.Empty, 0, 0),
owner4 = new MarbleSackOwner(string.Empty, string.Empty, 0, 0);    

while(inputFile.hasNextLine()){
        nameFromFile = inputFile.next();
        colorFromFile = inputFile.next();
        capacityFromFile = inputFile.nextInt();
        currentCountFromFile = inputFile.nextInt();

        owner1 = new MarbleSackOwner(nameFromFile, colorFromFile,
                                    capacityFromFile, currentCountFromFile);


        nameFromFile = inputFile.next();
        colorFromFile = inputFile.next();
        capacityFromFile = inputFile.nextInt();
        currentCountFromFile = inputFile.nextInt();

        owner2 = new MarbleSackOwner(nameFromFile, colorFromFile,
                                    capacityFromFile, currentCountFromFile);

        nameFromFile = inputFile.next();
        colorFromFile = inputFile.next();
        capacityFromFile = inputFile.nextInt();
        currentCountFromFile = inputFile.nextInt();

        owner3 = new MarbleSackOwner(nameFromFile, colorFromFile,
                                    capacityFromFile, currentCountFromFile);

        nameFromFile = inputFile.next();
        colorFromFile = inputFile.next();
        capacityFromFile = inputFile.nextInt();
        currentCountFromFile = inputFile.nextInt();

        owner4 = new MarbleSackOwner(nameFromFile, colorFromFile,
                                    capacityFromFile, currentCountFromFile);

    }

Java无法识别循环外循环中创建的对象

2 个答案: