关于Java中double精度丢失原因详情

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	// 定义数组长度
    private static final int LEN = 64;

    public static void paddingString(double n, StringBuilder sb, int len) {
        if (len < 0) {
            return;
        }
        if (n > 1) {
            n = n - 1;
            paddingString(n, sb, len);
        } else if (n < 1) {
            n *= 2;
        }

        if (n > 1) {
            sb.append(1);
            paddingString(n, sb, --len);
            return;
        } else if (n < 1) {
            sb.append(0);
            paddingString(n, sb, --len);
            return;
        } else {
            sb.append(1);
            return;
        }
    }

    private static byte[] setBitArray(String s) {
        byte[] arr = new byte[LEN];
        int temp;
        for (int i = LEN; i > 0; i--) {
            temp = s.charAt(i - 1) - 48;
            arr[i - 1] = (byte) temp;
        }

        return arr;
    }

    public static double binaryToDouble(byte[] s) {
        BigDecimal two = new BigDecimal(2);
        BigDecimal bigDecimal = new BigDecimal(0);
        BigDecimal temp = BigDecimal.ONE;
        BigDecimal temp1;
        for (int i = 0; i < s.length; i++) {

            temp = temp.divide(two);
            if (s[i] > 0) {
                int a = s[i];
                temp1 = new BigDecimal(a);
                bigDecimal = bigDecimal.add(temp.multiply(temp1));
            }
        }
        return bigDecimal.doubleValue();
    }

    public static String doubleToBinary(double n) {
        StringBuilder stringBuffer = new StringBuilder(LEN);
        // 填充并得到二进制结果
        paddingString(n, stringBuffer, LEN);
        int len;
        if ((len = stringBuffer.length()) > LEN + 1) {
            return stringBuffer.toString().substring(0, LEN + 1);
        } else {
            return stringBuffer.toString().substring(0, len);
        }
    }

    public static byte[] bytesAdd(byte[] a, byte[] b) {
        byte[] arr = new byte[LEN];
        for (int i = LEN - 1; i > 0; i--) {
            arr[i] = (byte) (arr[i] + a[i] + b[i]);
            if (arr[i] > 1) {
                arr[i] -= 2;
                arr[i - 1] = 1;
            }
        }
        return arr;
    }

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	public static void main(String[] args) {
        String s = doubleToBinary(.1); // 转成二进制字符串
        byte[] bytes = setBitArray(s); // 转成二进制数组 (一)
        double d = binaryToDouble(bytes); // 在转double, 反向验证结果的准确性
        System.out.println("十进制: " + d);

        System.out.println("========下面同理=========");
        
        String s1 = doubleToBinary(.2);
        byte[] bytes1 = setBitArray(s1); // (二)
        double d1 = binaryToDouble(bytes1);
        System.out.println("十进制: " + d1);
		
        byte[] add = bytesAdd(bytes, bytes1); // 二进制数组累加 (三)
        System.out.println("result: " + binaryToDouble(add)); // 将数组转换为小数
    }