java.lang.StringIndexOutOfBoundsException

Question

这是一个将十六进制转换为字符串的代码，但在字符串大小不超过 62 个字符之前它可以正常工作？

public static String hexToString(String hex)
        {       
           StringBuilder output = new StringBuilder();
           for (int i = 0; i < hex.length(); i+=2)
           {
            String str = hex.substring(i, i+2);
            output.append((char)Integer.parseInt(str, 16));
           }
           return(output.toString());
        }

java.lang.StringIndexOutOfBoundsException: String index out of range: 62 at java.lang.String.substring(Unknown Source) at HEX.hexToString(HEX.java:36) at HEX.main(HEX.java:56)

Answer 1

i+2在String str = hex.substring(i, i+2);是问题所在。即使i < hex.length() , i+2如果 hex.length() 太大很奇怪。