将HexaDecimal字符串转换为普通字符串

In one of my application i have converted a string to hexadecimal value and i have stored the hexadecimal value in a file. later i am retrieving the values from the file as it is in hexadecimal value can you suggest me how to make it to a normal string so that i can have the application more easy to builtIn one of my application i have converted a str