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我有下面的代碼從文件讀取數據並將其存儲在一個字符串變量，現在當我運行它，它給了我一個字符串越界異常。我該如何解決這個錯誤？爲什麼我得到一個字符串越界異常
運行命令和錯誤：
Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 1882
at java.lang.String.charAt(String.java:694)
at IfCounter2.main(IfCounter2.java:92)
代碼：
import java.io.*;
public class IfCounter2
{
// method to check if there is a single-line comment
public static boolean lineAComment(String line)
{
if (line.contains("//"))
return true;
return false;
}
// method to check if there is a multi-line comment start
public static boolean multiLineCommentStart(String line)
{
if (line.contains("/*"))
return true;
return false;
}
// method to check if there is a multi-line comment end
public static boolean multiLineCommentEnd(String line)
{
if (line.contains("*/"))
return true;
return false;
}
public static void main(String[] args) throws IOException
{
// variable to keep track of ifs
int ifCount = 0;
// check how many arguments are passed
int numArgs = args.length;
// look at all the arguments
// they don't want to count ifs in comments ************************************ --nocomment was entered
if (args[0].equals("--nocomments"))
{
// create a new BufferReader for the file that will be at args 1
BufferedReader reader = new BufferedReader(new FileReader (args[1]));
String line = null;
StringBuilder stringBuilder = new StringBuilder();
String ls = System.getProperty("line.separator");
// read from the text file
boolean multiLineComment = true;
// ignore comments as we store data in a String variable
while ((line = reader.readLine()) != null)
{
if (!multiLineCommentStart(line))
{
multiLineComment = true;
} // end if
if (multiLineComment)
{
if (!multiLineCommentEnd(line))
{
multiLineComment = false;
} // end if
} // end if
if (!lineAComment(line) && !multiLineComment)
{
stringBuilder.append(line);
stringBuilder.append(ls);
} // end if
} // end while
// create a new string with stringBuilder data
String tempString = stringBuilder.toString();
System.out.println(tempString);
// create one last string to look for our valid if(s) in,
// with ALL whitespace removed
String compareString = tempString.replaceAll("\\s","");
//System.out.println(compareString);
for (int i = 0; i < compareString.length(); i++)
{
if (compareString.charAt(i) == ';' || compareString.charAt(i) == '}' || compareString.charAt(i) == '{' || compareString.charAt(i) == '\n')
{
i++;
if (compareString.charAt(i) == 'i')
{
i++;
if (compareString.charAt(i) == 'f')
{
i++;
if (compareString.charAt(i) == '(')
ifCount++;
} // end if
} // end if
} // end if
} // end for
} // end if (comments option)
// else ******************************************************** count ifs as usual
/*else
{
for (int c = 0; c <= numArgs; c++)
{
// create a new BufferReader
BufferedReader reader2 = new BufferedReader(new FileReader (args[c]));
String line2 = null;
StringBuilder stringBuilder2 = new StringBuilder();
String ls2 = System.getProperty("line.separator");
// read from the text file
while ((line2 = reader2.readLine()) != null)
{
stringBuilder2.append(line2);
stringBuilder2.append(ls2);
}
// create a new string with stringBuilder data
String tempString2 = stringBuilder2.toString();
// create one last string to look for our valid if(s) in
// with ALL whitespace removed
String compareString2 = tempString2.replaceAll("\\s","");
// check for valid if(s)
for (int i = 0; i < compareString2.length(); i++)
{
if (compareString2.charAt(i) == ';' || compareString2.charAt(i) == '}' || compareString2.charAt(i) == '{') // added opening "{" for nested ifs :)
{
i++;
if (compareString2.charAt(i) == 'i')
{
i++;
if (compareString2.charAt(i) == 'f')
{
i++;
if (compareString2.charAt(i) == '(')
ifCount++;
} // end if
} // end if
} // end if
} // end for
} // end if (else option)
} // end for
*/
// print the number of valid "if(s) with a new line after"
System.out.println(ifCount + "\n");
}
}
您是否嘗試過使用調試器並在第92行設置斷點？從那裏，你可以檢查變量並精確確定爲什麼傳遞給'charAt'的索引是無效的。 –
什麼行代碼在92行？ –
我不確定這段代碼的目的是什麼，但顯然是不正確的。如果它應該解析Java代碼..所以你不能識別是（true）; （假）;在一行中作爲兩個ifs;）你將只計算一個。 –