用于将IEEE 754 double转换为字符串的纯Java代码

public class DoubleToStringConverter {
    public static String doubleToString(double value) {
        StringBuilder sb = new StringBuilder();
        if (value < 0) {
            sb.append("-");
            value = -value;
        }
        int exponent = 0;
        while (value >= 10) {
            value /= 10;
            exponent++;
        }
        while (value < 1) {
            value *= 10;
            exponent--;
        }
        sb.append((int) value);
        if (exponent != 0) {
            sb.append("E");
            sb.append(exponent);
        }
        return sb.toString();
    }
}