从Java JDBC调用oracle函数

Question

We have a Oracle function we are trying to call from JDBC. It takes 3 inputs (String, Number and Date) and returns 1 Number:

create or replace function     mww_avgcost
(in_prd_lvl_number prdmstee.prd_lvl_number%type,
in_org_lvl_number orgmstee.org_lvl_number%type,
in_sales_date     prcmstee.prc_from_date%type)
RETURN NUMBER
AS
begin   

Using Java JDBC code as follows:

        String call = "{ ? = call PMM.MWW_AVGCOST(?, ?, ?) }";
        CallableStatement cstmt = conn.prepareCall(call);
        cstmt.registerOutParameter(1, java.sql.Types.INTEGER);
        cstmt.setString(2, productNumber);
        cstmt.setInt(3, storeNumber);

        // convert XML input to SQL date
        java.sql.Date sqlDate = new java.sql.Date(saleDate.toGregorianCalendar().getTimeInMillis());

        cstmt.setDate(4, sqlDate);
        cstmt.execute();
        BigDecimal resultFromFunction = cstmt.getBigDecimal(1);
        log.info("resultFromFunction:" + resultFromFunction);

The result always returns 1 though and not the proper number. We have run it fine from SQL Developer with the same parameters and it looks fine. Is this is proper way to call a SQL function from JDBC?

Answer 1

Looks like your have a type mismatch. You're setting the out parameter to an sql integer but then getting it as a BigDecimal.
If the sql function returns an integer then use: callableStatement.getInt(1)

If the sql function returns a floating point number, then use callableStatement.registerOutParameter(1, java.sql.Types.DOUBLE) and callableStatement.getDouble(1)

The mapping for java and oracle types can be found here: https://docs.oracle.com/javase/1.5.0/docs/guide/jdbc/getstart/mapping.html

If you really do need BigDecimal because of rounding problems or something, then your sql function should return DECIMAL or NUMERIC. And you should set your out parameter and getBigDecimal() as you're doing now.