Question

public class BookStore {

        /**************************************************
    Kim works in the school bookstore, selling pens, notebooks, etc.
    They have prices written in a notebook.  When prices change 
    they must cross out old prices - that's messy.  They want
    a computer program that stores and displays prices.
    Item names and prices are stored in PARALLEL ARRAYS.
     ***************************************************/

        String[] items = {
            "pencil", "pen", "sharpie", "notebook A", "notebook B",
                "eraser", "tippex", "usb stick", "glue", "tape"
        };

        float[] prices = {
            0.75f, 1.50f, 1.20f, 1.90f, 2.50f,
            0.50f, 1.75f, 5.00f, 1.25f, 2.00f
        };
        public static void main(String[] args) {
            String name = "";
            do {
                name = input("Type the name of an item");
                float price;
                price = getPrice(name);
                if (price > 0) {
                    output(name + " = " + price);
                } else {
                    output(name + " was not found");
                }
            } while (name.length() > 0); // type nothing to quit
        }

        float getPrice(String name) // search for name, return price
        { // the price is not case-sensitive
            for (int x = 0; x < prices.length; x = x + 1) {
                if (items[x].equalsIgnoreCase(name)) // not cases-sensitive
                {
                    return prices[x];
                }
            }
            return 0.00f;
        }

        static public String input(String prompt) {
            return javax.swing.JOptionPane.showInputDialog(null, prompt);
        }

        static public void output(String message) {
            javax.swing.JOptionPane.showMessageDialog(null, message);
        }
    }

所以我运行此代码并收到以下错误：

运行：

线程中的异常＆＃34; main＆＃34; java.lang.RuntimeException：无法编译的源代码


非静态方法getPrice（java.lang.String）无法从BookStore.main中的静态上下文引用（BookStore.java:26）


Java结果：1

建立成功（总时间：2秒）

这让我感到困惑，因为我试图仅仅强调静态＆＃39; getPrice（）前面的修饰符，但会产生一大堆其他错误。也许你们其中一个人可以帮助我..？任何帮助表示赞赏。

Answer 1

像这样：

public static void main(String[] args) {
        BookStore bs = new BookStore();

        String name = "";
        do {
            name = bs.input("Type the name of an item");
            float price;
            price = bs.getPrice(name);
            if (price > 0) {
                output(name + " = " + price);
            } else {
                output(name + " was not found");
            }
        } while (name.length() > 0); // type nothing to quit
    }

非静态方法不能从Java中的静态上下文中引用？

1 个答案: