Hello Florian,
Thank you for reply. With genius tip from my friend java-developer, the final solution is the follow:
var search = $.request.parameters.get('query');
var arrSearch = [];
var i;
var conn = $.db.getConnection();
query = "SELECT C1, C2 FROM T1 "
if(filterRegion.length>0){
query += "WHERE C2 IN (";
arrSearch = search.split(",");
for (i = 0; i< arrSearch.length-1; i++){
query += "?,";
}
query += "?) ";
pstmt = conn.prepareStatement(query);
for(i=0; i < arrSearch.length; i++){
pstmt.setString(i+1, arrSearch[i]);
}