我正在嘗試用 Java 制作一個計算器 GUI，但是我不知道如何將“7/7”轉(zhuǎn)換為雙精度數(shù)。我嘗試過將其直接轉(zhuǎn)換為雙精度數(shù)，但無法使其工作。private class handler implements ActionListener{ String answerString = ""; int answerDouble; public void actionPerformed(ActionEvent e) { if(e.getSource() == clear) { answerString = ""; result.setText(answerString); } if(e.getSource() == openBracket) { answerString = answerString + "("; result.setText(answerString); } if(e.getSource() == closeBracket) { answerString = answerString + ")"; result.setText(answerString); } if(e.getSource() == divide) { answerString = answerString + "/"; result.setText(answerString); } if(e.getSource() == seven) { answerString = answerString + "7"; result.setText(answerString); } if(e.getSource() == equal) { answerDouble = Integer.parseInt(answerString); answerString = Double.toString(answerDouble); result.setText(answerString); } }}它應(yīng)該顯示 1 代表 7/7，但在命令行上輸出錯誤。
1 回答
慕桂英4014372
TA貢獻1871條經(jīng)驗 獲得超13個贊
您可以使用JavaScript ScriptEngine來計算此類表達式：
String expression = "7/7";
ScriptEngine scriptEngine = new ScriptEngineManager().getEngineByName("JavaScript");
System.out.println(scriptEngine.eval(expression)); // you will have to handle ScriptException
輸出：
1
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