Question

尝试通过try / catch块在我的计算器项目中添加除零异常：

private class Calculate implements ActionListener {

        public void actionPerformed(ActionEvent e) {
            try {
                if (operation.equals("/")) {
                    display.setText(Double.toString(getResult() / Double.parseDouble(display.getText())));
                    setResult(Double.parseDouble(display.getText()));
                }
                else if (operation.equals("*")) {
                        display.setText(Double.toString(getResult() * Double.parseDouble(display.getText())));
                        setResult(Double.parseDouble(display.getText()));
                }
                else if (operation.equals("-")) {
                    display.setText(Double.toString(getResult() - Double.parseDouble(display.getText())));
                        setResult(Double.parseDouble(display.getText()));
                }
                else if (operation.equals("+")) {
                        display.setText(Double.toString(getResult() + Double.parseDouble(display.getText())));
                        setResult(Double.parseDouble(display.getText()));
                }
                if (display.getText().endsWith(".0")) {
                    display.setText(display.getText().replace(".0", ""));
                }
                calculationMade = true;
                operation = "";
            }
            catch (IllegalArgumentException exc) {
                display.setText("You cannot divide by zero!");
            }
        }
    }

但是这样它仍然在文本字段中写了“Infinity”。有人可以建议我哪里错了吗？

Answer 1

使用double时，零分区返回Double.POSITIVE_INFINITY或Double.NEGATIVE_INFINITY（取决于操作数符号）

System.out.println(1.0d/0d);
System.out.println(-1.0d/0d);
System.out.println(1.0d/-0d);
System.out.println(-1.0d/-0d);

只有非小数运算才会在零除法时抛出异常。例外不是IllegalArgumentException，而是ArithmeticException。

例外处理麻烦

1 个答案: