// -----------------------------------------------------------------------------
// ConnectionExample.java
// -----------------------------------------------------------------------------
/*
* =============================================================================
* Copyright (c) 1998-2009 Jeffrey M. Hunter. All rights reserved.
*
* All source code and material located at the Internet address of
* http://www.idevelopment.info is the copyright of Jeffrey M. Hunter and
* is protected under copyright laws of the United States. This source code may
* not be hosted on any other site without my express, prior, written
* permission. Application to host any of the material elsewhere can be made by
* contacting me at [email protected].
*
* I have made every effort and taken great care in making sure that the source
* code and other content included on my web site is technically accurate, but I
* disclaim any and all responsibility for any loss, damage or destruction of
* data or any other property which may arise from relying on it. I will in no
* case be liable for any monetary damages arising from such loss, damage or
* destruction.
*
* As with any code, ensure to test this code in a development environment
* before attempting to run it in production.
* =============================================================================
*/
import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;
/**
* -----------------------------------------------------------------------------
* The following class provides an example of using JDBC to connect to an
* Oracle database. The one phase of JDBC that is the most difficult and
* hard to achieve portability, is when connecting. This phase requires
* that the Java database application specify driver-specific information that
* JDBC requires in the form of a database URL.
*
* If you run into problems while trying to simply make a connection, check
* if they match any of the following:
*
* Connection fails with the message "Class no found"
* --------------------------------------------------
* This message usually results from not having the JDBC driver in your
* CLASSPATH. Ensure that if you are including *.zip and *.jar in your
* CLASSPATH, that your enter them explicity. If you put all of your *.class
* files and the ojdbc14.jar file containing the Oracle-JDBC driver into
* /u02/lib, your CLASSPATH should read /u02/lib:/u02/lib/ojdbc14.jar.
*
* Connection fails with the message "Driver no found"
* ---------------------------------------------------
* In this case, you did not register the JDBC driver with the DriverManager
* class. This example application describes several ways to register a
* JDBC driver. Sometimes developers using the Class.forName() method of
* registering a JDBC driver encounter an inconsistency between the JDBC
* specification and some JVM implementations. You should thus use the
* Class.forName().netInstance() method as a workaround.
*
* When attempting to make a database connection, your application must first
* request a java.sql.Connection implementation from the DriverManager. You will
* also use a database URL and whatever properties your JDBC driver requires
* (generally a user ID and password). The DriverManager in turn will search
* through all of the known java.sql.Driver implementations for the one that
* connects with the URL you provided. If it exhausts all the implementations
* without finding a match, it throws an exception back to your application.
*
* Once a Driver recognizes your URL, it creates a database connection using
* the properties you specified. It then provides the DriverManager with a
* java.sql.Connection implementation representing that database connection. The
* DriverManager then passes that Connection object back to the application.
*
* At this point, you may be wondering how the JDBC DriverManager learns about
* a new driver implementation. The DriverManager actually keeps a list of
* classes that implement that java.sql.Driver interface. Something needs to
* register the Driver implementation for any potential database drivers it
* might require with the DriverManager. JDBC requires a Driver class to
* register itself with the DriverManager when it is initiated. The act of
* instantiating a Driver class thus enters it in the DriverManager's list.
*
* This class (ConnectionExample) provides three ways to register a driver.
* -----------------------------------------------------------------------------
* @version 1.0
* @author Jeffrey M. Hunter ([email protected])
* @author http://www.idevelopment.info
* -----------------------------------------------------------------------------
*/
public class ConnectionExample {
final String driverClass = "oracle.jdbc.driver.OracleDriver";
final String connectionURLThin = "jdbc:oracle:thin:@jeffreyh3:1521:CUSTDB";
final String connectionURLOCI = "jdbc:oracle:oci8:@CUSTDB_JEFFREYH3";
final String userID = "scott";
final String userPassword = "tiger";
final String queryString = "SELECT" +
" user " +
" , TO_CHAR(sysdate, 'DD-MON-YYYY HH24:MI:SS') " +
"FROM dual";
/**
* The following method provides an example of how to connect to a database
* by registering the JDBC driver using the DriverManager class. This method
* requires you to hardcode the loading of a Driver implementation in
* your application. this alternative is the least desirable since it
* requires a rewrite and recompile if your database or database driver
* changes.
*/
public void driverManager() {
Connection con = null;
Statement stmt = null;
ResultSet rset = null;
try {
System.out.print("\n");
System.out.print("+-------------------------------+\n");
System.out.print("| USING DriverManager CLASS |\n");
System.out.print("+-------------------------------+\n");
System.out.print("\n");
System.out.print(" Loading JDBC Driver -> " + driverClass + "\n");
DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());
System.out.print(" Connecting to -> " + connectionURLThin + "\n");
con = DriverManager.getConnection(connectionURLThin, userID, userPassword);
System.out.print(" Connected as -> " + userID + "\n");
System.out.print(" Creating Statement...\n");
stmt = con.createStatement ();
System.out.print(" Opening ResultsSet...\n");
rset = stmt.executeQuery(queryString);
while (rset.next()) {
System.out.println(" Results...");
System.out.println(" User -> " + rset.getString(1));
System.out.println(" Sysdate -> " + rset.getString(2));
}
System.out.print(" Closing ResultSet...\n");
rset.close();
System.out.print(" Closing Statement...\n");
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
if (con != null) {
try {
con.rollback();
} catch (SQLException e1) {
e1.printStackTrace();
}
}
} finally {
if (con != null) {
try {
System.out.print(" Closing down all connections...\n\n");
con.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
/**
* The following method provides an example of how to connect to a database
* by registering the JDBC driver using the jdbc.drivers property. The
* DriverManager will load all classes listed in this property
* automatically. This alternative works well for applications with a
* command-line interface, but might not be so useful in GUI applications
* and applets. This is because you can specify properties at the command
* line.
*/
public void jdbcDriversProperty() {
Connection con = null;
Statement stmt = null;
ResultSet rset = null;
try {
System.out.print("\n");
System.out.print("+-------------------------------+\n");
System.out.print("| USING jdbc.drivers PROPERTY |\n");
System.out.print("+-------------------------------+\n");
System.out.print("\n");
System.out.print(" Loading JDBC Driver -> " + driverClass + "\n");
System.setProperty("jdbc.drivers", driverClass);
System.out.print(" Connecting to -> " + connectionURLThin + "\n");
con = DriverManager.getConnection(connectionURLThin, userID, userPassword);
System.out.print(" Connected as -> " + userID + "\n");
System.out.print(" Creating Statement...\n");
stmt = con.createStatement ();
System.out.print(" Opening ResultsSet...\n");
rset = stmt.executeQuery(queryString);
while (rset.next()) {
System.out.println(" Results...");
System.out.println(" User -> " + rset.getString(1));
System.out.println(" Sysdate -> " + rset.getString(2));
}
System.out.print(" Closing ResultSet...\n");
rset.close();
System.out.print(" Closing Statement...\n");
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
if (con != null) {
try {
con.rollback();
} catch (SQLException e1) {
e1.printStackTrace();
}
}
} finally {
if (con != null) {
try {
System.out.print(" Closing down all connections...\n\n");
con.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
/**
* The following method provides an example of how to connect to a database
* by registering the JDBC driver using the Class.forName() method. This
* complex expression is a tool for dynamically creating an instance of
* a class when you have some variable representing the class name. Because
* a JDBC driver is required to register itself whenever its static
* initializer is called, this expression has the net effect of registering
* your driver for you.
*
* NOTE: When using Class.forName("classname"), the JVM is supposed to
* be sufficient. Unfortunately, some Java virtual machines do
* not actuall call the static intitializer until an instance of
* a class is created. As a result, newInstance() should be
* called to guarantee that the static initializer is run for
* all virtual machines.
*
* This method is by far the BEST in that it does not require hardcoded
* class names and it runs well in all Java environments. In real-world
* applications, you should use this method along with a properties file
* from which you load the name of the driver.
*
*/
public void classForName() {
Connection con = null;
Statement stmt = null;
ResultSet rset = null;
try {
System.out.print("\n");
System.out.print("+-------------------------------+\n");
System.out.print("| USING Class.forName() |\n");
System.out.print("+-------------------------------+\n");
System.out.print("\n");
System.out.print(" Loading JDBC Driver -> " + driverClass + "\n");
Class.forName(driverClass).newInstance();
System.out.print(" Connecting to -> " + connectionURLThin + "\n");
con = DriverManager.getConnection(connectionURLThin, userID, userPassword);
System.out.print(" Connected as -> " + userID + "\n");
System.out.print(" Creating Statement...\n");
stmt = con.createStatement ();
System.out.print(" Opening ResultsSet...\n");
rset = stmt.executeQuery(queryString);
while (rset.next()) {
System.out.println(" Results...");
System.out.println(" User -> " + rset.getString(1));
System.out.println(" Sysdate -> " + rset.getString(2));
}
System.out.print(" Closing ResultSet...\n");
rset.close();
System.out.print(" Closing Statement...\n");
stmt.close();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
if (con != null) {
try {
con.rollback();
} catch (SQLException e1) {
e1.printStackTrace();
}
}
} finally {
if (con != null) {
try {
System.out.print(" Closing down all connections...\n\n");
con.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
/**
* The following method provides an example of how to connect to a database
* using the OCI JDBC Driver.
*
*/
public void jdbcOCIDriver() {
Connection con = null;
Statement stmt = null;
ResultSet rset = null;
try {
System.out.print("\n");
System.out.print("+-------------------------------+\n");
System.out.print("| USING OCI Driver |\n");
System.out.print("+-------------------------------+\n");
System.out.print("\n");
System.out.print(" Loading JDBC Driver -> " + driverClass + "\n");
Class.forName(driverClass).newInstance();
System.out.print(" Connecting to -> " + connectionURLOCI + "\n");
con = DriverManager.getConnection(connectionURLOCI, userID, userPassword);
System.out.print(" Connected as -> " + userID + "\n");
System.out.print(" Creating Statement...\n");
stmt = con.createStatement ();
System.out.print(" Opening ResultsSet...\n");
rset = stmt.executeQuery(queryString);
while (rset.next()) {
System.out.println(" Results...");
System.out.println(" User -> " + rset.getString(1));
System.out.println(" Sysdate -> " + rset.getString(2));
}
System.out.print(" Closing ResultSet...\n");
rset.close();
System.out.print(" Closing Statement...\n");
stmt.close();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
if (con != null) {
try {
con.rollback();
} catch (SQLException e1) {
e1.printStackTrace();
}
}
} finally {
if (con != null) {
try {
System.out.print(" Closing down all connections...\n\n");
con.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
/**
* Sole entry point to the class and application.
* @param args Array of String arguments.
* @exception java.lang.InterruptedException
* Thrown from the Thread class.
*/
public static void main(String[] args)
throws java.lang.InterruptedException {
ConnectionExample conExample = new ConnectionExample();
conExample.classForName();
Thread.sleep(5000);
conExample.jdbcDriversProperty();
Thread.sleep(5000);
conExample.driverManager();
Thread.sleep(5000);
conExample.jdbcOCIDriver();
}
}
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