java - 我收到如下错误消息 : Exception in thread "main" java. lang.StringIndexOutOfBoundsException: String index out of range: 0

Question

我收到如下错误消息:线程“main”中出现异常

java.lang.StringIndexOutOfBoundsException: String index out of range: 0
    at java.lang.String.charAt(Unknown Source)
    at emp.MainClass.main(MainClass.java:52)

使用下面的代码，如何缓解这个问题？

public class MainClass {
        //main class
public static void main(String[] args){
       // variable

    String input;


    boolean salaryError = true;
    boolean dependentError = true;
    boolean nameError = true;
    boolean charError = true;

    Employee emp1 = new Employee();
    displayDivider("EMPLOYEE INFORMATION");


    do{
    input = getInput(" First Name");
    nameError = nameValidate(input);
    if(!nameError){
        JOptionPane.showMessageDialog(null,"Incorrect Input. Please Try Again!");
    }
    }while(!nameError);
    emp1.setfirstName(input);
    do{
    input = getInput(" Last Name");
    nameError =nameValidate(input);
    if(!nameError){
        JOptionPane.showMessageDialog(null,"Incorrect Input. Please Try Again!");
    }
    }while(!nameError);
    emp1.setlastName(input);
    do{

    input = getInput(" Gender: M or F");

    charError = characterChecker(input.charAt(0));
    if(!charError){
        JOptionPane.showMessageDialog(null,"Incorrect Input. Please Try Again!");
    }
    }while(!charError);

    char g = input.charAt(0);
    emp1.setgender(g);// validates use of M or F for gender

    do{
    input = getInput(" number of dependents");
    dependentError = integerChecker(input);
    if(!dependentError){
        JOptionPane.showMessageDialog(null,"Incorrect Input. Please Try Again!");
    }
    }while(!dependentError);
    emp1.setdependents(Integer.parseInt(input));

    do{ 
    input = getInput(" annual salary");
    salaryError = doubleChecker(input);
    if(!salaryError){
        JOptionPane.showMessageDialog(null,"Incorrect Input. Please Try Again!");
    }
    } while(!salaryError);
    emp1.setannualSalary(Double.parseDouble(input));

    emp1.displayEmployee();//displays data for emp1

    Employee emp2 = new Employee("Speed","Racer",'M',1,500000.00);
    displayDivider("EMPLOYEE INFORMATION");
    emp2.displayEmployee();// displays data for emp2

    terminateApplication(); //terminates application

    System.exit(0);//exits program

}//end of main

    // gets Input information
 public static String getInput(String data)
  {
      String input = "";
      input = javax.swing.JOptionPane.showInputDialog(null,"Enter your " + data);
      return input;
  }// end getInput information

    // The display divider between employees
 public static void displayDivider(String outputLab)
  {
      System.out.println("********" + outputLab + "********"); 
}// end display divider

    // Terminates the application
 public static void terminateApplication()
  {   javax.swing.JOptionPane.showMessageDialog(null,"Thanks for the input!"); 

  }// end terminateApplication 
 public static boolean doubleChecker(String inStr){
     boolean outBool = true;
     double tmpDbl = 0.0;
     try{
         tmpDbl = Double.parseDouble(inStr);
         if(tmpDbl <= 0)
             throw new IllegalArgumentException();
     }
     catch (Exception e){

         outBool = false;
     }
     return outBool;
 }

 public static boolean integerChecker(String intStr){
     boolean outBool = true;
     int tmpInt = 0;
     try{
         tmpInt = Integer.parseInt(intStr);
         if(tmpInt <= 0)
             throw new IllegalArgumentException();
     }
     catch (Exception e){

         outBool = false;
     }
     return outBool;
 }

 public static boolean nameValidate(String str){
        for(char ch : str.toCharArray()){
            if(!Character.isDigit(ch)){
                return true;
            }
        }
        return false;
    }
 public static boolean characterChecker(char gen){
     boolean outBool = true;

     try{

         if(!( gen ==( 'M') || gen ==('F')))
             throw new IllegalArgumentException();
     }
     catch (Exception e){

         outBool = false;
     }
     return outBool;
 }
}//end of Main Class

Answer 1

您的字符串长度为 0。在访问其元素之前，请确保 string.length() > 0。问题出在异常表明问题所在的行。