Code39中的校验和（Check Sum）实现

 

private int getCharIndex(char c) throws InvalidAtributeException{
		if( c >= '0' && c <= '9' ){
			return c - 48;
		} else if( c >= 'A' && c <= 'Z' ){
			return c - 55;
		} else if( c == '-' ){
			return 36;
		} else if( c == '.' ){
			return 37;
		} else if( c == ' ' ){
			return 38;
		} else if( c == '$' ){
			return 39;
		} else if( c == '/' ){
			return 40;
		} else if( c == '+' ){
			return 41;
		} else if( c == '%' ){
			return 42;
		} else {
			throw new InvalidAtributeException("[Code39] The text contains unsuported chars.");
		}
	}

 

private int getChar(int c) throws InvalidAtributeException{
        if( c >= 0 && c <= 9 ){
            return c + 48;
        } else if( c >= 10 && c <=  35){
            return c + 55;
        } else if( c == 36 ){
            return 45;
        } else if( c == 37 ){
            return 46;
        } else if( c == 38 ){
            return 32;
        } else if( c == 39 ){
            return 36;
        } else if( c == 40 ){
            return 47;
        } else if( c == 41 ){
            return 43;
        } else if( c == 42 ){
            return 37;
        } else {
            throw new InvalidAtributeException("[Code39] The text contains unsuported chars.");
        }
    }

 

public String computeCheckSum(String texto) throws InvalidAtributeException {
		int check = 0;
		for( int i = 0; i < texto.length(); i++ ){
			check += getCharIndex(texto.charAt(i));
		}
		return (Character.valueOf((char)getChar(check%43)).toString());
	}

 

@Test
	public void testComputeCheckSum() throws InvalidAtributeException {
		String code = "TEXT";
		System.out.println(computeCheckSum(code));
	}