Author is Mr. Ramanjaneyulu Dayinaboyina  you can reach at   d_ramu2002@yahoo.com

 

Tomcat screens

 

 

 

 

 

 

location: class HelloWorld

        public void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException

  ^ 6 errors

In the above servlet-api.jar  is not recgonised so where your servlet-api.jar file exist to set path to that and now compile it

Setting classpath for the servlet-api.jar

***e:\apache-tomcat-6.0.14\webapps\Myservlets\WEB-INF>set classpath=%classpath%;e:\apache-tomcat-6.0.14\lib\servlet-api.jar

now compile

E:\apache-tomcat-6.0.14\webapps\Myservlets\WEB-INF>javac HelloWorld.java

E:\apache-tomcat-6.0.14\webapps\Myservlets\WEB-INF>dir

02/15/2011  12:55 AM    <DIR>          classes

02/15/2011  02:28 AM               803 HelloWorld.class

02/15/2011  02:15 AM               464 HelloWorld.java

02/15/2011  12:20 AM    <DIR>          lib

02/15/2011  02:10 AM               246 web.xml

               3 File(s)          1,513 bytes     4 Dir(s) 

import java.io.*;    Mr.D.Ramanjaneyulu you can reach me at d_ramu2002@yahoo.com  program-2

import java.sql.*;

public class ramuexce

{

                public static void main(String s[])  throws Exception

                {

try

{

                                   //general method-1

                                Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

                                Connection con=DriverManager.getConnection("Jdbc:Odbc:oradsn","ramu","ram");

                                  //method-2

 

                                  Statement st=con.createStatement();

                                ResultSet rs=st.executeQuery("select * from student");

/*for(int i=1;i<=3;i++) //the index must start from the 1 only generally people are facing trouble by putting the value for index '0'

                                                {

                                                                Object o=rs.getObject(i);

                                                                System.out.println("result:"+o);}*/

// 2nd method this is the polished way of writing CODE to retrive  the data from the database

while(rs.next())

                                {

System.out.println(rs.getInt(1));// if we put beyond the existing column we will get an error which will totally stop the program even no partial execuation

System.out.println(rs.getString(2));

System.out.println(rs.getInt(3));// here i am mentaioning INT datatype insted of Float datatype now you will get the warning which allows you partial execuation

System.out.print("\n");

                                }

//implementing the SQLEXCEPTION  class for knowing the EXCEPTION for knowing  details

//implementing SQLWARNING  CLASS for knowing SQLWARNINGS AT COMPILETIME

SQLWarning w= rs.getWarnings();

 

System.out.println("now you are in warnings blockTHE FIRST WARNING IS ");

System.out.println("THE MESSAGE IS"+w.getMessage());

System.out.println("THE STATE IS "+w.getSQLState());

System.out.println("THE ERROR NUMBER IS "+w.getErrorCode());

w.getNextWarning();

System.out.println("THE NEXT WARNING IS ");

System.out.println("THE MESSAGE IS"+w.getMessage());

System.out.println("THE STATE IS "+w.getSQLState());

System.out.println("THE ERROR NUMBER IS "+w.getErrorCode());

                                                               

rs.close();

st.close();                              

con.close();

}//end of try

catch(SQLException e)

{

System.out.println("THE EXCPTIONS ARE  "+e.getMessage());

}// end of exception

}// end of main method

}//end of main class

 

import java.io.*;

import java.sql.*;

class ramuorcl{

public static void main(String s[])  //throws Exception{

try

{             //general method-1

                                Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

                                Connection con=DriverManager.getConnection("Jdbc:Odbc:oradsn","ramu","ram");

                                  //method-2   Statement st=con.createStatement();

                                ResultSet rs=st.executeQuery("select * from student");

/*for(int i=1;i<=3;i++) //the index must start from the 1 only generally people are facing trouble by putting the value for index '0'

                                                {

                                                                Object o=rs.getObject(i);

                                                                System.out.println("result:"+o);

 

                                                }*/

//implementing the DATABASEMETADATA class for knowing the database details

DatabaseMetaData dbmd=con.getMetaData();

System.out.println("THE PRODUCTNAME IS "+dbmd.getDatabaseProductName());

System.out.println("URL IS"+dbmd.getURL());

System.out.println("THE USERNAME IS "+dbmd.getUserName());

System.out.println("THE DRIVER NAME IS "+dbmd.getDriverName());

System.out.println("THE VERSION NAME IS "+dbmd.getDriverVersion());

System.out.println("----------------------------------------------------");                  

// to know about these total details we must put the array and retrive with help of  a while loop until return the null by the loop

//implementing the RESULTSETMETADATA class for knowing the TABLE SCHEMA details

ResultSetMetaData rsmd=rs.getMetaData();

System.out.println("URL IS"+rsmd.getColumnName(1));

System.out.println("THE USERNAME IS "+rsmd.getColumnTypeName(1));

System.out.println("THE COLUMN COUNT IS "+rsmd.getColumnCount());

System.out.println("----------------------------------------------------");  

}

//implementing the SQLEXCEPTION  class for knowing the EXCEPTION for knowing  details

//implementing SQLWARNING  CLASS for knowing SQLWARNINGS AT COMPILETIME

SQLWarning w= rs.getWarnings();

while(w !=null)

{

System.out.println("THE MESSAGE IS"+w.getMessage());

System.out.println("THE STATE IS "+w.getSQLState());

System.out.println("THE ERROR NUMBER IS "+w.getErrorCode());

w.getNextWarning();

}

//this willnot work because it has been defined in ORACLE       

// 2nd method this is the polished way of writing CODE to retrive  the data from the database

System.out.println(rs.getInt(1)); System.out.println(rs.getString(2)); System.out.println(rs.getFloat(3));

System.out.print("\n");

                                }                                                              

rs.close();  st.close();   con.close();

}}

catch(SQLException e)

{

System.out.println("THE EXCPTIONS ARE  "+e.getMessage());}}