Java connection Simple instance of Oracle database

package cn.com.login.dao;import java.sql.connection;import java.sql.drivermanager;import  java.sql.preparedstatement;import java.sql.resultset;public class logindao {     public string getusername (String usercode) {    connection  con = null;    preparedstatement pre = null;     ResultSet result = null;    String userName =  "";     try {class.forname ("Oracle.jdbc.driver.OracleDriver");  // Load the Oracle driver System.out.println ("Start trying to connect to the database!") "); string url =  "jdbc:oracle:"  +  "thin:@10.10.19.19:1521:db123"; string user =  "System"; string password =  "scc123456"; Con = drivermanager.getconnection (url, user,  password); SYSTEM.OUT.PRINTLN ("Connection succeeded"); string sql =  "select username  from web01_test where usercode = ? "; Pre = con.preparestatement (SQL);p re.setstring (1, usercode); Result = pre.executequery ( );while  (Result.next ())  {username = result.getstring ("UserName");}}  catch  (exception e)  {e.printstacktrace ();}  finally {    try {    if  (result !=  NULL)  {    result.close ();    }    if  ( Pre != null)  {    pre.close ();    }     if  (Con != null)  {    con.close ();     }}  catch  (Exception e2)  {e2.printstacktrace ();}     }    return username;    }}

Java connection Simple instance of Oracle database