Hex ASCII间的转换
public class StringToHex{

public String convertStringToHex(String str){

char[] chars = str.toCharArray();

StringBuffer hex = new StringBuffer();
for(int i = 0; i < chars.length; i++){
hex.append(Integer.toHexString((int)chars[i]));
}

return hex.toString();
}

public String convertHexToString(String hex){

StringBuilder sb = new StringBuilder();
StringBuilder temp = new StringBuilder();

//49204c6f7665204a617661 split into two characters 49, 20, 4c...
for( int i=0; i<hex.length()-1; i+=2 ){

//grab the hex in pairs
String output = hex.substring(i, (i + 2));
//convert hex to decimal
int decimal = Integer.parseInt(output, 16);
//convert the decimal to character
sb.append((char)decimal);

temp.append(decimal);
}
System.out.println("Decimal : " + temp.toString());

return sb.toString();
}

public static void main(String[] args) {

StringToHex strToHex = new StringToHex();
System.out.println("\n***** Convert ASCII to Hex *****");
String str = "I Love Java!";
System.out.println("Original input : " + str);

String hex = strToHex.convertStringToHex(str);

System.out.println("Hex : " + hex);

System.out.println("\n***** Convert Hex to ASCII *****");
System.out.println("Hex : " + hex);
System.out.println("ASCII : " + strToHex.convertHexToString(hex));
}
}