在我的程序中,我必须从给定的字母等级和数字等级计算GPA。 在第一个对话框但是,如果我点击取消它给了我numberFormatException空错误,如果我键入字符串,它会给我NumberFormatException输入字符串错误。 我必须在我的程序中使用try-catch,并且我已经尝试过它了。无论如何,我可以使用try-catch方法处理这两个异常。我还希望用户能够接受地为字母等级和数字等级选项键入1和2没有别的。Java,如何处理JOptionPane NumberFormatException输入字符串和NumberFormatException:空错误?
以下是节目的代码:
import javax.swing.JOptionPane;
class CalcGPA{
public static void main (String [] args){
String questionOfOptions = "What type of grade do you wish to enter?\n";
String letterGradeOption = "Press 1- for letter (A,C,etc)\n";
String numericGradeOption= "Press 2-for numeric(89,68,etc)";
String message= questionOfOptions
+letterGradeOption
+numericGradeOption;
String endingMessage = "The corresponding GPA is";
String calculatedGPA="0" ;
String randomString="kc;lc[ ams[xas";
String userResponseString="0";
int userResponseNumerical=0;
char characterValue='0';
do {
userResponseString=JOptionPane.showInputDialog
(null,
message,
"GPA Calculator",
JOptionPane.OK_CANCEL_OPTION);
try {
userResponseNumerical= Integer.parseInt(userResponseString);
} catch(NumberFormatException.forInputString ex) {
System.exit(0);
}
userContinuationOption= JOptionPane.showConfirmDialog
(null,
"Do You Want to Continue? ",
"GPA Calculator",
JOptionPane.YES_NO_OPTION);
if(userContinuationOption==JOptionPane.NO_OPTION) {
System.exit(JOptionPane.NO_OPTION);
}
switch(userResponseNumerical){
case 1:
String userGradeResponse = JOptionPane.showInputDialog
(null,
"Enter a Grade.",
"GPA Calculator",
JOptionPane.INFORMATION_MESSAGE);
if (userGradeResponse.equals("A")) {
calculatedGPA ="4.";
} else if (userGradeResponse.equals("B")) {
calculatedGPA=" 3.";
} else if (userGradeResponse.equals("C")) {
calculatedGPA=" 2.";
} else if (userGradeResponse.equals("D")) {
calculatedGPA=" 1.";
} else if(userGradeResponse.equals("F")) {
calculatedGPA=" 0.";
} else {
JOptionPane.showMessageDialog
(null,
"Improper input ",
"Error",
JOptionPane.ERROR_MESSAGE);
break;
}
JOptionPane.showMessageDialog
(null,
endingMessage+" "+calculatedGPA,
"GPA Calculator",
JOptionPane.INFORMATION_MESSAGE);
break;
case 2:
String userNumericString= JOptionPane.showInputDialog
(null,
"Enter a Numeric Grade.",
"GPA Calculator",
JOptionPane.INFORMATION_MESSAGE);
int userNumericGradeResponse=0;
Integer.parseInt(userNumericString);
if(userNumericGradeResponse>=80) {
calculatedGPA=" 4.";
} else if (userNumericGradeResponse>70) {
calculatedGPA=" 3.";
} else if (userNumericGradeResponse>60) {
calculatedGPA=" 2.";
} else if (userNumericGradeResponse>50) {
calculatedGPA=" 1.";
} else if(userNumericGradeResponse>=0 &&
userNumericGradeResponse<50) {
calculatedGPA=" 0.";
}
break;
default:
JOptionPane.showMessageDialog
(null,
"Improper input",
"Error",
JOptionPane.INFORMATION_MESSAGE);
break;
}
int userContinuationOption = JOptionPane.showConfirmDialog
(null,
"Do You Want to Continue? ",
"GPA Calculator",
JOptionPane.YES_NO_OPTION);
if(userContinuationOption==JOptionPane.NO_OPTION) {
System.exit(JOptionPane.NO_OPTION);}
}
while(true);
}
}
在另一个catch块中做同样的事情?虽然系统出口似乎有点苛刻。接受性?这是一个强大的方法! –