Help using Java to retrieve XMLType returned from PL/SQL stored object

Question

Hi,
Please bear with me if this is a trivial question. I'm brand new to Java, JDBC, and XML DB. I've been spinning my wheels on this for a few hours now.
I have a table:
XMLDB_USER@xmldb64> desc my_test_table
Name                                      Null?    Type
ID                                                 NUMBER(9)
DOC                                                SYS.XMLTYPE(XMLSchema "http:
                                                    //www.myproquest.com/Global_
                                                    Schema_v3.0.xsd" Element "RE
                                                    CORD") STORAGE BINARYI've written a trivially simple PL/SQL function to retrieve the DOC column, based on the ID passed to it.
create or replace function get_doc(goid in number) return xmltype is
  doc_content xmltype;
begin
  select doc into doc_content from my_test_table where id = goid;
  return doc_content;
end;
/Up to here, everything works fine. I wrote a small anonymous PL/SQL block, and proved that I can call the PL/SQL function successfully.
Now, I want to implement in Java. This is where I get confused.
Currently my code looks like this:
import java.sql.*;
import oracle.jdbc.*;
import oracle.jdbc.OracleTypes;
import oracle.jdbc.pool.OracleDataSource;
import oracle.xdb.*;
import java.io.*;
import java.lang.StringBuilder;
import java.sql.Clob;
class MyJava
  public static void main(String args[]) throws SQLException, IOException
    Clob xml = null;
    System.out.print("Connecting to the database...");
    System.out.flush();
    OracleDataSource ods = new OracleDataSource();
    String URL = "jdbc:oracle:thin:@//pqhdb201.aa1.pqe:1522/xmldb64";
    ods.setURL(URL);
    ods.setUser("xmldb_user");
    ods.setPassword("xmldb_user");
    Connection conn = ods.getConnection();
    System.out.println("connected.");
    System.out.println("GOID to be retrieved is " + args[0]);
    CallableStatement cs1 = null;
try {
    cs1 = conn.prepareCall( "{? = call get_doc (?)}" );
    cs1.registerOutParameter(1,OracleTypes.OPAQUE,"XMLType");
    cs1.setString(2,args[0]);
    cs1.execute();
//    xml = XMLType.createXML(cs1.getOPAQUE(1));
    xml = (Clob) cs1.getObject(1);
//    System.out.println(((XMLType)xml).getStringVal());
//    System.out.println(xml.getClobVal());
    System.out.println(xml.getCharacterStream());
  finally {
     if(cs1!=null) cs1.close();
     if(conn!=null) conn.close();
}This compiles, but when I run, I get:
pqhdb201:[xmldb64]:(/home/oracle/xmldb_scripts):$java MyJava 91455713
Connecting to the database...connected.
GOID to be retrieved is 91455713
Exception in thread "main" java.sql.SQLException: invalid name pattern: XMLDB_USER.XMLType
        at oracle.jdbc.oracore.OracleTypeADT.initMetadata(OracleTypeADT.java:553)
        at oracle.jdbc.oracore.OracleTypeADT.init(OracleTypeADT.java:469)
        at oracle.sql.OpaqueDescriptor.initPickler(OpaqueDescriptor.java:237)
        at oracle.sql.OpaqueDescriptor.<init>(OpaqueDescriptor.java:104)
        at oracle.sql.OpaqueDescriptor.createDescriptor(OpaqueDescriptor.java:220)
        at oracle.sql.OpaqueDescriptor.createDescriptor(OpaqueDescriptor.java:181)
        at oracle.jdbc.driver.NamedTypeAccessor.otypeFromName(NamedTypeAccessor.java:83)
        at oracle.jdbc.driver.TypeAccessor.initMetadata(TypeAccessor.java:89)
        at oracle.jdbc.driver.T4CCallableStatement.allocateAccessor(T4CCallableStatement.java:689)
        at oracle.jdbc.driver.OracleCallableStatement.registerOutParameterInternal(OracleCallableStatement.java:157)
        at oracle.jdbc.driver.OracleCallableStatement.registerOutParameter(OracleCallableStatement.java:202)
        at oracle.jdbc.driver.OracleCallableStatementWrapper.registerOutParameter(OracleCallableStatementWrapper.java:1356)
        at MyJava.main(MyJava.java:29)As you can see from the commented lines, I've tried several different approaches, based on various examples from Oracle documentation and various samples found on the net. My problem, I think, is that I have a fundamental disconnect somewhere. Objects? Types? Different methods? getClobVal? getStringVal? getCharacterStream? I'm still trying to get up to speed on all the lingo and terminology, and, as a result, I suspect I'm asking the wrong questions, and getting wrong results.
Based on the simple example above, my table and PL/SQL function definitions, can someone help me fill in the gaps of what I'm missing in terms of the Java code?
Thanks!
-Mark

Answer 1

Hi, I´ve been working on an application that return an XMLTYPE from an schema package, the XML is generated in a query, not read it in a table, and use that variable in a JSP.
The DDL of the package function is this:
CREATE OR REPLACE
PACKAGE BODY pkg_modulos
IS
    FUNCTION obtenerModulos (pAnio IN NUMBER DEFAULT 2011)
        RETURN XMLTYPE
    IS
        x    XMLTYPE;
    BEGIN
        SELECT  XMLELEMENT ("tree", XMLAttributes (0 AS "id"),
                    (SELECT  DBMS_XMLGEN.getxmltype(DBMS_XMLGEN.newcontextfromhierarchy('SELECT level,
                                          XMLElement("item",
                                                                      XMLAttributes(
                                                                m.idmodulo as "id",
                                                                m.nombre AS "text"))
                            FROM            modulos m
             WHERE m.anio = 2011
CONNECT BY   PRIOR m.idmodulo = m.padre
START WITH   m.padre IS NULL'))
                        FROM     DUAL))
                        arbolXML
          INTO  x
          FROM  DUAL;
        RETURN x;
    END;                                                                         
END;   as far as I see there shouldn´t be any problems with this code
The problem is on the JSP code
this is my code:
<?xml version="1.0" encoding="UTF-8"?>
<%@ page contentType="text/xml; charset=UTF-8" import="java.io.*,java.lang.*,java.sql.*,java.util.*,oracle.jdbc.*,oracle.xdb.*, oracle.jdbc.OracleTypes,oracle.jdbc.pool.OracleDataSource"%>
<%
  Connection dbconn;
  OracleDataSource ods = new OracleDataSource();
  OracleCallableStatement stmt;
    try
         String hostname="localhost";
         String dbname="xe";
         String usr="seguridad";
         String pass="seguridad";
         String URL = "jdbc:oracle:thin:@"+hostname+":1521:"+dbname;
         ods.setURL(URL);
        ods.setUser(usr);
        ods.setPassword(pass);
         dbconn = ods.getConnection();
          String st=request.getParameter("st").toString();
          int np=Integer.parseInt(request.getParameter("np").toString());     
          stmt = (OracleCallableStatement)dbconn.prepareCall( "begin ? := "+st+"; end;" );
          stmt.registerOutParameter(1,OracleTypes.OPAQUE,"SYS.XMLTYPE");          
          stmt.execute();
          XMLType xml = null;
          xml = (XMLType) stmt.getObject(1);
          System.out.println(xml.getStringVal());
          stmt.close();
          dbconn.close();
    catch (SQLException s)
      out.println("SQL Error: " + s.toString());
       System.out.println("SQL Error: " + s.toString());
%>I´m getting te error:
SQL Error: java.sql.SQLException: inconsistent java and sql object types: SYS.XMLTYPE
Making a debbuging I identified that the exception is been raised in this line:
xml = (XMLType) stmt.getObject(1);I´ve been checking a lot of online documentation but I´ve not been able to make it work
If anyone could help me please, I don´t know what else to do
Thanks... sorry for the english