如何解决字符串索引越界问题？

Question

家庭作业要求我使用单个输入字符串并创建4个不同的变量，并允许用户继续输入更多数据。 一切正常但我收到以下错误。

线程“main”中的异常java.lang.StringIndexOutOfBoundsException：begin 1，end 0，length 0 at
java.base / java.lang.String.checkBoundsBeginEnd（String.java:3410）位于EmployeeData.main的java.base / java.lang.String.substring（String.java:1883）（EmployeeData.java:24）

我有谷歌和搜索几个线程，我无法找到任何有用的东西。 我只是不确定从哪里开始。

import java.util.Scanner; 

public class EmployeeData 
{

    public static void main(String[] args)
    {
    Scanner scanner=new Scanner(System.in);

        String custInp;
        String fName = "";
        String lName = "";
    int empID;
    double wage;
    //initation loop    
    int newInput=1;
    while(newInput==1)
        {
        //input in single string
        System.out.println("Please enter First name, last name, emp ID
        and wage.  (include space inbetween each)");
        custInp = scanner.nextLine();      
        //cut string into variables
        fName = splitNext(custInp, ' ');
        custInp = custInp.substring(fName.length() + 1,
        custInp.length());
        lName = splitNext(custInp, ' ');
        custInp = custInp.substring(lName.length() + 1,
        custInp.length());
        String temp = splitNext(custInp, ' ');
        empID = Integer.parseInt(temp);
        custInp = custInp.substring(custInp.indexOf(' ') + 1,
        custInp.length());
        wage = Double.parseDouble(custInp);
        //set data
        Employee emp = new Employee(fName, lName, empID, wage);
        //get data
        System.out.println(fName + " " + lName + " " + empID + " " +
        wage);
        System.out.println("Employee Name: " + emp.getFirstName() + "
        " + emp.getLastName());
        System.out.println("Employee ID:   " + emp.getEmpID());
        System.out.println("Employee Wage: " + emp.getWage());
        System.out.println("");
        //decide to continue or not
        System.out.println("Do you want to add more? 1=Yes or 2=no");
        newInput = scanner.nextInt();
        //THIS IS WHERE the issue happens
        }
    }


  public static String splitNext(String s, char delim)
  {
    //location of first space character in s  
    int delimIndex = s.indexOf(delim); 

    //require that next is at least 1 char long
    if(delimIndex > 0)
    {
      //set next to all chars in s preceding first space found
      String next = s.substring(0, delimIndex);

      //truncate beginning of s so that s.find(' ') can reach second              
      s = s.substring(delimIndex + 1, s.length());

      return next;
    }

    return "";
  }
}

循环应允许您输入新输入并再次显示信息。

任何帮助都会非常感谢。

Answer 1

您的问题是使用Scanner.nextLine()和Scanner.nextInt() 。 在一起使用时应该小心，因为它们可能会导致意外行为。 您可以阅读Scanner类的JavaDocs以获取更多详细信息。 而不是newInput = scanner.nextInt() ，尝试使用newInput = Integer.parseInt(scanner.nextLine())读取字符串并将其转换为整数。