1.浮点格式示例

IEEE.png

2.上代码

public class Main {

static StringBuilder endValue;

public static void main(String[] args) {

    String data = "B8D1B717";

    //String data = "42987C32";

     //String data = "461C4000";

    endValue = new StringBuilder();

    StringBuffer buffer = new StringBuffer();

    char[] chars = data.toCharArray();

    for (int i = 0; i < data.length(); i++) {

        buffer.append(hexToBin(chars[i]));

    }

    System.out.println(buffer);

    getIEEEFloatValue(buffer);

}

public static void getIEEEFloatValue(StringBuffer buffer) {

    if (buffer.substring(0, 1).equals("0")) {

//为正

    } else {

 //为负

        endValue.append("-");

    }

    String E = buffer.substring(1, 9);

    String M = buffer.substring(9, buffer.length());

    Integer EDec = Integer.parseInt(E, 2);

    System.out.println("E:" + EDec);

    Integer MDec = Integer.parseInt(M, 2);

    System.out.println("M:" + MDec);

//        指数

//        System.out.println("指数:" + (float)(2 >> (14)));

    System.out.println("指数:" + Math.pow(2, EDec - 127));

    System.out.println("尾数:" + (1.00 + (float) MDec / 8388608.00));

    System.out.println("结果:" + (Math.pow(2, EDec - 127)) * (1.00 + (float) MDec / 8388608.00));

    endValue.append(String.format("%.2f", (Math.pow(2, EDec - 127)) * (1.00 + (float) MDec / 8388608.00)));

    System.out.println("最终结果:" + endValue);

}

private static String hexToBin(char charAt) {

    // TODO Auto-generated method stub

    switch (charAt) {

        case '0':

            return "0000";

        case '1':

            return "0001";

        case '2':

            return "0010";

        case '3':

            return "0011";

        case '4':

            return "0100";

        case '5':

            return "0101";

        case '6':

            return "0110";

        case '7':

            return "0111";

        case '8':

            return "1000";

        case '9':

            return "1001";

        case 'A':

        case 'a':

            return "1010";

        case 'B':

        case 'b':

            return "1011";

        case 'C':

        case 'c':

            return "1100";

        case 'D':

        case 'd':

            return "1101";

        case 'E':

        case 'e':

            return "1110";

        case 'F':

        case 'f':

            return "1111";

    }

    return null;

}

}