java - 在字符串上使用 line.split 时获取 ArrayIndexOutOfBound

Question

获取indexOutOfBound。文件保存成功后。我打开该文件来执行以下任务:查找每个项目的总 cost、totalCount 和总和。不知道为什么我会越界。错误指出

totalCost =+ Double.parseDouble(index[1].trim());

源代码:

 Scanner data = new Scanner(new File("registryCopy.txt"));

    while(data.hasNext()){
        String line = data.nextLine();
        System.out.println(line);

        String[] index = line.split("\\t");
        totalCost += Double.parseDouble(index[1].trim());
        totalCount += Integer.parseInt(index[2].trim());

        sum = totalCost/totalCount;

    }

错误

Error: "main" java.lang.ArrayIndexOutOfBoundsException: 1 

即:totalCost += Double.parseDouble(index[1].trim());

由于某些原因，它不会分割线。文本文件如下:

item1 15.00 3
item2 15 2
item3 14 3

文件之前已创建并提示用户输入该数据。来源:

while(userInput.charAt(0)!='n'){
        /**
         * Need only one PrintWriter out0 i.e, then I either use the userbased name OR fixed name creation i.e registryCopy.txt(true will
         * not overwrite the file but go to the next).
         */
        PrintWriter out0 = new PrintWriter(new BufferedWriter(new FileWriter("registryCopy.txt", true)));

    System.out.print("Enter item name: ");
    itemName = kybd.next();//user String
    out0.print(itemName + " ");

    System.out.print("Enter item price: $");
    price = kybd.next();
    out0.print(price + " ");

    System.out.print("Enter item quantity: ");
    quantity = kybd.next();
    out0.println(quantity);


    System.out.print("Do you have another item to scan? Yes(y) or No(n): ");
    userInput= kybd.next();
    out0.flush();
    }//end of whileLoop

更新1:你们太棒了，成功了。当你在芝加哥时请给我啤酒。谢谢

输出源代码:

sum = totalCost*totalCount;
    System.out.println("");
    System.out.println(totalCost);
    System.out.println(totalCount);
    System.out.println(sum);

标准操作流程:

项目1 15.00 3

项目2 15 2

项目3 14 3

项目5 10.00 3

第 5 项 12

bla 11 5

面包1 15

项目14 5 3

76.0

46

3496.0

Answer 1

您对 split 的调用会在选项卡上拆分；您的输入似乎有其他类型的空格分隔标记。

要分割任何类型的空白，请使用"\\s":

String[] index = line.split("\\s");

\s 是 regular expression代表以下任意一个:' '、'\t'、'\n'、'\x0B'、'\f'、'\r'。