Java十六进制与IEEE754浮点数互相转换，支持单双精度

Java十六进制与IEEE754浮点数互相转换，支持单双精度

本文连接：https://www.cnblogs.com/muphy/p/15250939.html

IEEE754Utils.javapackage com.moefon.power.spri

import java.math.BigDecimal; import java.math.BigInteger; /*** * IEE754 浮点数转换工具 * 单精度校验：47218100 = 41345.0、 47849A0D = 67892.1016 * 双精度校验：4721810047849A0D = 45442749783852262460186723560194048 * * @author: 若非 * @date: 2021/9/10 8:58 */ @Remind("校验：47218100 = 41345.0、 47849A0D = 67892.1016") public class IEEE754Utils {

    /** * 字节数组转IEEE 754 * * @param bytes 长度4或者8 * @author: 若非 * @date: 2021/9/10 16:57 */
    public static BigDecimal bytesToSingle(byte[] bytes) { if (bytes.length > 8) { throw new ArrayIndexOutOfBoundsException("转化失败，字节超出整型大小！"); } String hex = new BigInteger(bytes).toString(16); return hexToSingle(hex, bytes.length * 8); } /** * 字节数组转IEEE 754 * * @param hex * @param bitLen 32或者64 * @author: 若非 * @date: 2021/9/10 16:57 */
    private static BigDecimal hexToSingle(String hex, int bitLen) { if (StringUtils.isEmpty(hex)) { return BigDecimal.valueOf(0); } if (bitLen == 32) { int i = Integer.parseInt(hex, 16); float v = Float.intBitsToFloat(i); return new BigDecimal(v); } if (bitLen == 64) { long l = Long.parseLong(hex, 16); double d = Double.longBitsToDouble(l); return new BigDecimal(d); } return BigDecimal.valueOf(0); } /** * IEEE 754字符串转十六进制字符串 * * @param f * @author: 若非 * @date: 2021/9/10 16:57 */
    public static String singleToHex(float f) { int i = Float.floatToIntBits(f); String hex = Integer.toHexString(i); return hex; } /** * IEEE 754字符串转十六进制字符串 * * @param d * @author: 若非 * @date: 2021/9/10 16:57 */
    public static String singleToHex(double d) { long l = Double.doubleToRawLongBits(d); String hex = Long.toHexString(l); return hex; } //下面测方法是方便c++等没有类似功能的时候做参考

    /** * 十六进制字符串转IEEE 754 * * @author: 若非 * @date: 2021/9/10 16:57 */
    /*public static BigDecimal hexToSingle(String hex, int bitLen) { if (StringUtils.isEmpty(hex) || bitLen != 32 && bitLen != 64) { return BigDecimal.valueOf(0); } String binaryString = StringUtils.fillString(new BigInteger(hex, 16).toString(2), "0", bitLen, true); //String binaryString = String.format("%32s", new BigInteger(hex, 16).toString(2)).replace(' ', '0'); int exponentBitLength = hex.length() == 8 ? 8 : 11; int mantissaBitLength = (hex.length() * 4) - exponentBitLength - 1; char s = binaryString.charAt(0);//符号位 String e = binaryString.substring(1, exponentBitLength + 1); String m = binaryString.substring(exponentBitLength + 1); Double bias = Math.pow(2, exponentBitLength - 1) - 1; int exponent = Integer.valueOf(e, 2) - bias.intValue(); long mantissa = Long.valueOf(m, 2); //BigDecimal bigDecimal = (new BigDecimal(1).add(new BigDecimal(mantissa).multiply(new BigDecimal(Math.pow(2, -mantissaBits))))).multiply(new BigDecimal(Math.pow(2, exponent))); Double res = (1 + (mantissa * Math.pow(2, -mantissaBitLength))) * Math.pow(2, exponent); BigDecimal bigDecimal = new BigDecimal(res); if (s == '1') { return new BigDecimal(0).subtract(bigDecimal); } return bigDecimal; }*/

    /** * IEEE 754转十六进制字符串 * * @author: 若非 * @date: 2021/9/10 16:57 */
    /*public static String singleToHex(float fv) { String negative = "0"; if (fv < 0) { negative = "1"; fv = fv * -1; } int thirty; int integer = Float.valueOf(fv).intValue(); float decimal = fv - integer; String rear; //0-22位存放的值 String medim = "";//23位到29位 String integerBinaryString = Integer.toBinaryString(integer); String decimalBinaryString = ConvertUtils.unsignedDecimalToBinary(decimal); if (integerBinaryString.length() > 1) { //左移 30为存1 thirty = 1; int exponent = integerBinaryString.length() - 2; rear = integerBinaryString.substring(1) + decimalBinaryString; if (rear.length() > 23) { rear = rear.substring(0, 23); } else { for (int i = rear.length(); i <= 22; i++) { rear += "0"; } } medim = Integer.toBinaryString(exponent); medim = StringUtils.fillString(medim, "0", 7, true); } else if ("1".equals(integerBinaryString)) { //不需要移动位数 30位0 剩下的补1 指数部分 23-29位 //127-指数 23-29位正好七位最大值127 thirty = 0; rear = integerBinaryString.substring(1) + decimalBinaryString; if (rear.length() > 23) { rear = rear.substring(0, 23); } else { rear = StringUtils.fillString(medim, "0", 22, true); } medim = "1111111"; } else {//0 0 1111101 100 1100 1100 1100 1100 1100 //右移 30位存0 thirty = 0; int index = decimalBinaryString.indexOf("1");//找到第一个为1的位置索引 右移动的位数 int exponent = 127 - (index + 1); rear = decimalBinaryString.substring(index + 1); if (rear.length() > 23) { rear = rear.substring(0, 23); } else { rear = StringUtils.fillString(medim, "0", 22, true); } medim = Integer.toBinaryString(exponent); medim = StringUtils.fillString(medim, "0", 7, true); } String res = "" + negative + thirty + medim + rear; StringBuilder sb = new StringBuilder(); if (res.length() == 32) { for (int i = 0; i < 8; i++) { String binary = res.substring(4 * i, 4 * i + 4); sb.append(Constants.BIN_HEX_TABLE.get(binary)); } } return sb.toString(); }*/ }

 

StringUtils.java

public static String fillString(String src, String c, int len, boolean left) {
    if (StringUtils.isEmpty(src) || len <= src.length()) {
        return src;
    }
    int l = src.length();
    for (int i = 0; i < len - l; i++) {
        if (left) {
            src = c + src;
        } else {
            src += c;
        }
    }
    return src;
}

public static boolean isEmpty(Object content) {
    return content == null || "".equals(content);
}