How to dynamically set the PreparedStatement in java?

Question

I was trying to build a preparedStatement here is the example:

StringBuffer sqlStatement = new StringBuffer("Select * From APPLES where price =?");
 if (request.getPackagedDate() != null) {
                sqlStatement.append(" AND packaged_dt_tm >= ?");
           }
 if(request.getExpiredDate() != null) {
                sqlStatement.append(" AND expired_dt_tm <= ?");
           }
 if (request.getAppleType() != null) {
                sqlStatement.append(" AND TYPE LIKE ?");
           }}
 PreparedStatement retrieveAppleStatement = connection.getPreparedStatement(sqlStatement.toString());

so the three "if" statement is where it getting tricky, after the prepare statement built, I don't know how many variable I should set, the only way I'm doing right now is something like this:

retrieveAppleStatement.setString(1, request .getId());
if (hasPackagedTime && hasExpiredTime && hasType ) {
    statement .setLong(2, packagedTime );
    statement .setLong(3, expiredTime);
    statement .setString(4, (type+"%")); 
 }
else if (hasPackagedTime && ! hasExpiredTime && !hasType ) {
    statement .setLong(2, packagedTime));
 }
else if (hasPackagedTime && ! hasExpiredTime && hasType ) {
    statement .setLong(2, packagedTime);
    statement .setString(3, (type+"%")); 
 }
else if (hasPackagedTime && hasExpiredTime && !hasType ) {
    statement .setLong(2, packagedTime);
    statement .setLong(3, expiredTime);
 }
else if (!hasPackagedTime && hasExpiredTime && hasType ) {
    statement .setLong(2, expiredTime);
    statement .setString(3, (type + "%" ));
 }
else if (!hasPackagedTime && ! hasExpiredTime && hasType ) {
    statement .setString(2, (type + "%" )); 
 }
else if (!hasPackagedTime && hasExpiredTime && !hasType ) {
    statement .setLong(2, expiredTime);
 }

I have to listed all the combinations (not for all null because I don't need to set anything), it feels a little bit lame... Is there any better way doing this? Any way that we can set the value dynamically while creating the prepared statement?

Answer 1

Your solution looks fine to me but if you are using a lot of parameters then I would suggest to use NamedParameterStatement class. Syntax will remain same, just instead of parameter numbers you will be using parameter names.

Connection con=getConnection();
String query="select * from User where first_name=:firstname or last_name=:lastname";
NamedParameterStatement p=new NamedParameterStatement(con, query);
p.setString("firstname", "John");
p.setString("lastname", "Doe");
ResultSet rs=p.executeQuery();