Custom UDF function: Double numeric conversion to high precision bigdecimal__udf function

Import Java.math.BigDecimal;
Import Org.apache.hadoop.hive.ql.exec.UDF;
 * * This method returns the corresponding value of the BigDecimal type of a numeric value of type Double, where the style returned is a string type/public
class udfcastdouble  extends UDF
{public
    String evaluate (double number)
    {  
    	//doublevalue () is the original value for the double, because number is the encapsulated class object of double, is not a value
        BigDecimal db = new BigDecimal (Number.doublevalue ());
        The Toplainstring () method is the string
        Stringnumber = db.toplainstring ()
        , which returns the value of the BigDecimal without the digit segment. return stringnumber;
       
    }
    Use the main method to test public
    static void Main (string[] args) throws Exception
    {
        udfcastdouble o = new Udfcastdouble ();

        System.out.println (O.evaluate (2.001));
        System.out.println (O.evaluate (2.00));
    }
Test results:
2.000999999999999889865875957184471189975738525390625
2