Question

我是Java的新手，我无法弄清楚如何解决这个问题：线程＆＃34; main＆＃34;中的例外情况java.lang.StringIndexOutOfBoundsException：字符串索引超出范围：1

以下是整个代码：

ascii

非常感谢任何帮助。

Answer 1

问题在于，char ch = input.next().charAt(0);会读取两个字符，但不会＆＃34;消费＆＃34;用户按Enter键时生成的换行符。

然后调用input.nextLine()，将使用换行符（但现在这两个字符已被next()消耗，因此生成的字符串为空）。在空字符串上调用.charAt(1)会生成异常，因为空字符串中没有位置(1)（它的长度为0）。

相反，我建议你使用这样的东西：

//Step 2: Ask user to enter two characters
System.out.println("\nPlease enter two characters (1st character represents   the major and 2nd character represents the classification): ");

String majorAndClassification = "";
while( majorAndClassification.length() != 2 )
    majorAndClassification = input.nextLine();

char ch = majorAndClassification.charAt(0);
char ch1 = majorAndClassification.charAt(1);

这将确保用户输入两个字符 - 如果他没有，他将不得不再次尝试，直到他这样做。一个稍微好一点的选择当然是每次都打印出提示，如下：

//Step 2: Ask user to enter two characters  
String majorAndClassification = "";
while( majorAndClassification.length() != 2 ){
    System.out.println("\nPlease enter two characters (1st character represents   the major and 2nd character represents the classification): ");
    majorAndClassification = input.nextLine();
}

Answer 2

如果输入第二个输入的字符，由于charAt(1)，它会超出范围。只需将其更改为charAt(0)，因为您总是只读取输入的第一个字符：

char ch = input.next().charAt(0);
char ch1 = input.next().charAt(0);

它适用于两个输入：

i
3

还有i 3

Answer 3

致电

final char ch1 = input.nextLine().charAt(1);

期望读取整行，并获得第二个字母。但

char ch = input.next().charAt(0);

已经消耗了第一个字符。

所以你应该一次性阅读整个输入，然后（做更多检查，然后）获取你的字符。

//Step 2: Ask user to enter two characters
System.out.println("\nPlease enter two characters (1st character represents   the major and 2nd character represents the classification): ");
final String reply = input.nextLine();
final char ch = reply.charAt(0);
final char ch1 = reply.charAt(1);


//Step 3:  Print statement

Answer 4

尝试更改代码，使其在引用String的索引之前首先检查输入的长度。如下所示：

 //Step 2: Ask user to enter two characters
System.out.println("\nPlease enter two characters (1st character represents   the major and 2nd character represents the classification): ");
String inputNext = input.next();
String inputNextLine;
if(inputNext.length>0 && inputNextLine.length>0){
char ch = inputNext;
char ch1 = inputNextLine;


//Step 3:  Print statement 
switch(ch) 
{
    case 'i': major = "Information Technology";
    break;
    case 'c': major = "Computer Science";
    break;
    case 'm': major = "Mathematics";
    break;
    case 'p': major = "Physics";
    break;    
    case 'b': major = "Biology";
    break;
    case 'e': major = "Engineering";
    break;
    case 'h': major = "History";
    break; 
    case 'j': major = "Journalism";
    break;
    case 'a': major = "Art and Design";
    break;
    case 'l': major = "Literature";
    break;
    case 's': major = "Sport Medicine";
    break;

    default: System.out.println("\nInvalid Major Code");
    System.out.println("Please enter a character followed by an integer!");
    break;

}//end of switch

//Step 3:  Print statement 
switch(ch1)
{
    case '1': classification = "Freshman";
    break;
    case '2': classification = "Sophmore";
    break;
    case '3': classification = "Junior";
    break;
    case '4': classification = "Senior";
    break;    
    case '5': classification = "Graduate";
    break;
}
}

Answer 5

从char ch1 = input.nextLine().charAt(1);更改您的代码这个char ch1 = input.next().charAt(0);

您可以查看this，了解有关next（）和nextLine（）之间差异的详细信息

Java：如何处理字符串索引超出范围错误？

5 个答案: