Oracle Database Connection in Java Example

Details: Written by; Last Updated on 11 March 2020 | Print Email

This JDBC tutorial helps you write Java code to establish database connection with an Oracle database server – the first step to have Java applications working with one of the most popular database systems. Suppose you already had a version of Oracle database installed, such as Oracle Database Express Edition.

Table of content:

1. Download JDBC driver library for Oracle database
2. JDBC database URL for Oracle database
3. Register Oracle JDBC driver
4. Establish connection to Oracle database
5. Java Connect to Oracle Database Example program

1. Download JDBC driver library for Oracle database

To make a Java program talks with Oracle database, we need to have the Oracle JDBC driver (OJDBC) present in the classpath. Click here to visit Oracle's JDBC driver download page. Then select the JDBC driver version that matches Oracle database sever and JDK installed on your computer. Currently there are two main versions of OJDBC:

- OJDBC 8: certified with JDK 8, for Oracle database 11g and 12c.

- OJDBC 10: certified with JDK 10, for Oracle database 18c and 19c.

NOTE: Oracle requires users to have an Oracle account for downloading, so you may have to register an account if you don't have one.

Extract the downloaded archive, and place the ojdbc10.jar file under your project's classpath as usual as using any jar file.

If you use Maven, add the following dependency to the pom.xml file:

<dependency>     <groupId>com.oracle</groupId>     <artifactId>ojdbc8</artifactId>     <version>1.0</version>     <scope>system</scope>     <systemPath>d:/Path/To/Oracle/JDBC/ojdbc8.jar</systemPath> </dependency>

2. JDBC database URL for Oracle database

The syntax of database URL for Oracle database is as follows:

jdbc:oracle:<drivertype>:@<database>

jdbc:oracle:<drivertype>:<user>/<password>@<database>

Where:

drivertype can be thin, oci or kprb .
database can be in the form of hostname:port:SID or a TNSNAMES entry listed in the file tnsnames.ora reside on the client computer. The default port is 1521.

Oracle categorizes their JDBC driver into four different types, as described in the following table:

Driver type	Usage	drivertype
Thin Driver	For client-side use without an Oracle installation	thin
OCI Driver	For client-side use with an Oracle installation	oci
Server-Side Thin Driver	Same as Thin Driver, but runs inside an Oracle server to access a remote server	thin
Server-Side Internal Driver	Runs inside the target server	kprb

According to Oracle, if your JDBC client and Oracle database server are running on the same machine, you should use the OCI Driver because it is much faster than the Thin Driver (The OCI Driver can use Inter Process Communication – IPC, whereas the Thin Driver can use only network connection).

For example, if you want to connect user tiger with password scott to an Oracle database with SID productDB through default port on host dbHost using the Thin Driver, you can construct the URL as follows:

String url = "jdbc:oracle:thin:tiger/[email protected]:1521:productDB"

If using the OCI Driver:

String url = "jdbc:oracle:oci:tiger/[email protected]:1521:productDB" String url = "jdbc:oracle:oci:tiger/[email protected]:1521:productDB"

If you have a TNSNAMES entry productionDB in the tnsnames.ora file, you can construct the URL as follows:

String url = "jdbc:oracle:oci:@productionDB"

For the Server-Side Thin Driver, use the same URL as the Thin Driver.

For the Server-Side Internal Driver, use the following URLs:

String url = "jdbc:oracle:kprb:" String url = "jdbc:default:connection:"

Because in that environment, the driver actually runs within a default session, and the client is always connected so the connection should never be closed.

3. Register Oracle JDBC driver

The Oracle JDBC driver class name is oracle.jdbc.OracleDriver . You can register this driver as follows:

DriverManager.registerDriver(new oracle.jdbc.OracleDriver());

or:

Class.forName("oracle.jdbc.OracleDriver");

NOTE: Since Java 6 (JDBC 4.0), registering the driver explicitly as above becomes optional. As long as we put the ojdbc10.jar file in the classpath, JDBC driver manager can detect and load the driver automatically.

4. Establish connection to Oracle database

With JDBC, we can establish a database connection by calling the method getConnection() of the DriverManager class. There are three versions of this method:

- static Connection getConnection(String url)
- static Connection getConnection(String url, Properties info)
- static Connection getConnection(String url, String user, String password)

So we can have three ways for making a connection as follows:

Using only database URL for everything

In this method, we specify all connection properties in a single URL string, for example:

String dbURL = "jdbc:oracle:thin:tiger/[email protected]:1521:productDB"; Connection conn = DriverManager.getConnection(dbURL); if (conn != null) {     System.out.println("Connected"); }

That uses the Thin Driver to connect the user tiger with password scott to the database SID productDB running on the same machine through the default port 1521.

Using database URL, username and password

In this method, we pass the username and password as additional arguments to the method getConnetion(), for example:

String dbURL = "jdbc:oracle:thin:@localhost:1521:productDB"; String username = "tiger"; String password = "scott"; Connection conn = DriverManager.getConnection(dbURL, username, password);

Using database URL and Properties object

In this method, we use a java.util.Properties object to hold username, password and other additional properties. For example:

String dbURL = "jdbc:oracle:oci:@ProductDB"; Properties properties = new Properties(); properties.put("user", "scott"); properties.put("password", "tiger"); properties.put("defaultRowPrefetch", "20");  Connection conn = DriverManager.getConnection(dbURL, properties);

In this example, we are using the OCI Driver with a TNSNAMES entry ProductDB, and specifying an additional property defaultRowPrefetch which is the number of rows to prefetch from the server.

5. Java Connect to Oracle Database Example program

To demonstrate, we create a small example program below that establishes three different connections in 3 ways mentioned above, and finally close all the connections:

package net.codejava.jdbc;  import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.util.Properties;  /**  * This program demonstrates how to make database connection with Oracle  * database server.  * @author www.codejava.net  *  */ public class JdbcOracleConnection {      public static void main(String[] args) {          Connection conn1 = null;         Connection conn2 = null;         Connection conn3 = null;          try {             // registers Oracle JDBC driver - though this is no longer required             // since JDBC 4.0, but added here for backward compatibility             Class.forName("oracle.jdbc.OracleDriver");              // METHOD #1             String dbURL1 = "jdbc:oracle:thin:tiger/[email protected]:1521:productDB";             conn1 = DriverManager.getConnection(dbURL1);             if (conn1 != null) {                 System.out.println("Connected with connection #1");             }              // METHOD #2             String dbURL2 = "jdbc:oracle:thin:@localhost:1521:productDB";             String username = "tiger";             String password = "scott";             conn2 = DriverManager.getConnection(dbURL2, username, password);             if (conn2 != null) {                 System.out.println("Connected with connection #2");             }              // METHOD #3             String dbURL3 = "jdbc:oracle:oci:@ProductDB";             Properties properties = new Properties();             properties.put("user", "tiger");             properties.put("password", "scott");             properties.put("defaultRowPrefetch", "20");             conn3 = DriverManager.getConnection(dbURL3, properties);              if (conn3 != null) {                 System.out.println("Connected with connection #3");             }         } catch (ClassNotFoundException ex) {             ex.printStackTrace();         } catch (SQLException ex) {             ex.printStackTrace();         } finally {             try {                 if (conn1 != null && !conn1.isClosed()) {                     conn1.close();                 }                 if (conn2 != null && !conn2.isClosed()) {                     conn2.close();                 }                 if (conn3 != null && !conn3.isClosed()) {                     conn3.close();                 }             } catch (SQLException ex) {                 ex.printStackTrace();             }         }     } }

That's Java code example for making connection to Oracle database server. For visual howtos, watch the following video:

JDBC API References:

DriverManager Class Javadoc
Connection Interface Javadoc

About the Author:

Nam Ha Minh is certified Java programmer (SCJP and SCWCD). He started programming with Java in the time of Java 1.4 and has been falling in love with Java since then. Make friend with him on Facebook and watch his Java videos you YouTube.

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Oracle Database Connection in Java Example

Source: https://www.codejava.net/java-se/jdbc/connect-to-oracle-database-via-jdbc

Bruton Beirsinglat