[JAVA100 example]053, loading JDBC Driver

Import java.sql.*;


/**


* <P>TITLE:JDBC Connection Database </p>


* <p>description: This example demonstrates how to use JDBC to connect to an Oracle database and to demonstrate adding data and querying data. </p>


* <p>copyright:copyright (c) 2003</p>


* <p>Filename:JDBCConn.java</p>


* @version 1.0


*/


public class jdbcconn{


private String url= "";


private String username= "";


private String password= "";


/**


*<br> Method Description: Obtain data connection


*<br> input Parameters:


*<br> return Type: Connection Connection object


*/


public Connection Conn () {


try {


//load JDBC driver


class.forname ("Oracle.jdbc.driver.OracleDriver");


//CREATE DATABASE connection


Connection con = drivermanager.getconnection ("JDBC:ORACLE:THIN:@127.0.0.1:1521:ORCL", "Test", "test");


return con;


}catch (classnotfoundexception cnf) {


System.out.println ("Driver not find:" +cnf);


return null;


}catch (SQLException sqle) {


System.out.println ("Can´t Connection db:" +sqle);


return null;


} catch (Exception e) {


System.out.println ("Failed to load Jdbc/odbc driver.");


return null;


　　 }


　}


/**


*<br> Method Description: Execute query SQL statement


*<br> input parameters: Connection Con database connection


*<br> input parameter: String SQL SQL statement to execute


*<br> return type:


*/


public void query (Connection con, String sql) {


try{


if (con==null) {


throw new Exception ("Database connection can´t use!");


　　 }


if (sql==null) throw new Exception ("Check your parameter:´sql´! Don´t input null! ");


//Declaration Statements


Statement stmt = Con.createstatement ();


//Execute Query


ResultSet rs = stmt.executequery (SQL);


ResultSetMetaData Rmeta = Rs.getmetadata ();


//Get the number of data fields


int numcolumns = Rmeta.getcolumncount ();


while (Rs.next ())


　{


for (int i = 0;i< numcolumns;i++)


　　{


String stemp = rs.getstring (i+1);


System.out.print (stemp+ "");


　　}


System.out.println ("");


　}


}catch (Exception e) {


System.out.println ("Query error:" +e);


　　}


　}


/**


*<br> Method Description: Perform inserts, updates, deletes, and so on without returning a result set of SQL statements


*<br> input parameters: Connection Con database connection


*<br> input parameter: String SQL SQL statement to execute


*<br> return type:


*/


public void execute (Connection con, String sql) {


try{


if (con==null) return;


Statement stmt = Con.createstatement ();


stmt.executeupdate (SQL);


}catch (Exception e) {


System.out.println ("Execute error:sql =" +sql);


System.out.println (e);


　　}


　}


/**


*<br> Method Description: Example Demo


*<br> input Parameters:


*<br> return type:


*/


public void Demo () {


try{


jdbcconn oc = new Jdbcconn ();


Connection conn = Oc.conn ();


String sql = "INSERT into Tbl_user (Id,name,password) VALUES (Seq_user.nextval,´switch´,´haorenpingan´)";


Oc.execute (Conn,sql);


sql = "SELECT * from Tbl_user";


oc.query (Conn,sql);


Conn.close ();


}catch (SQLException se) {


System.out.println (SE);


}catch (Exception e) {


System.out.println (e);


　　}





　}


/**


*<br> Method Description: Main method


*<br> input Parameters:


*<br> return type:


*/


public static void Main (string[] arg) {


if (arg.length!=3) {


System.out.println ("Use:java jdbcconn URL username password");


return;


　　}


jdbcconn oc = new Jdbcconn ();


oc.url = arg[0];


Oc.username=arg[1];


OC.PASSWORD=ARG[2];


Oc.demo ();


　}


}