Build a Java application

This topic describes how to build a Java application with OceanBase Database and OceanBase Connector/J.

Prerequisites

• A basic database development environment is deployed.

• The Java environment on your computer is Java JDK 8.

• You have obtained the installation package of OceanBase Connector/J. If not, obtain it from OceanBase Download Center.

Procedure

Step 1: Obtain a database connection string

Obtain a database connection string from a database deployment engineer or administrator. For example:

obclient  -h100.88.xx.xx -usys@oracle -p****** -P2883

The database connection string contains parameters required for accessing OceanBase Database. Before you create an application, you can log in to OceanBase Database by using the database connection string to verify that the parameters are correct.

The parameters are described as follows:

• -h: the IP address for connecting to OceanBase Database, which is sometimes the IP address of an OceanBase Database Proxy (ODP).

• -u: the username for connecting to a tenant, in the format of username@tenant name#cluster name. In Oracle-compatible mode, the default username of the administrator is sys. The cluster name is not required when you directly connect to OceanBase Database, but is required when you connect to OceanBase Database through an ODP.

• -p: the user password.

• -P: the port for connecting to OceanBase Database, which is also the listening port of the ODP.

Step 2: Install the OceanBase Connector/J driver

Decompress the JAR package of OceanBase Connector/J, place it in the local /usr/share/java path, and set the temporary environment variables.

mv ./oceanbase-client-{version}.jar /usr/share/java
export CLASSPATH=/usr/share/java/oceanbase-client-{version}.jar:$CLASSPATH

Step 3: Write an application

Write the Java sample file Test.java as follows:

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.ResultSet;
import java.sql.Statement;

public class Test {
    public static void main(String[] args) {
        try {

            Class.forName("com.oceanbase.jdbc.Driver");
            Connection connection = DriverManager.getConnection("jdbc:oceanbase://172.30.xx.xx:2881/?pool=false&user=s**@oracle&password=******");
            System.out.println(connection.getAutoCommit());
            Statement sm = connection.createStatement();
            //Create a table named t_meta_form
            sm.executeUpdate("CREATE TABLE t_meta_form (name varchar(36) , id int)");
            //Insert data
            sm.executeUpdate("insert into t_meta_form values ('an','1')");
            //Query data and output the results
            ResultSet rs = sm.executeQuery("select * from t_meta_form");
            while (rs.next()) {
                String name = rs.getString("name");
                String id = rs.getString("id");
                System.out.println(name + ','+ id);
            }
            //Drop the table
            sm.executeUpdate("drop table t_meta_form");
        }catch (SQLException ex) {
            System.out.println("error!");
            ex.printStackTrace() ;
        }catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
}

Modify the database connection parameters in the code. The parameters are as follows, and the values are from the database connection string obtained in Step 1.

• url: The value is obtained from the -h and -P parameters, in the format of jdbc:oceanbase://IP:port/?pool=false. This specifies the IP address for connecting to OceanBase Database, which is usually an ODP address, and the port number for access.

• user: The value is obtained from the -u parameter. The username for connecting to a tenant, in the format of username@tenant name#cluster name. In Oracle-compatible mode, the default username of the administrator is sys. The cluster name is not required when you directly connect to OceanBase Database, but is required when you connect through an ODP.

• password: The value is obtained from the -p parameter. The user password.

Step 4: Run the application

After you edit the code, run the following command to compile:

javac Test.java

After the compilation is completed, execute the application. If the following results are returned, you have connected to OceanBase Database successfully, and the sample script is correctly executed:

java Test

true
an,1

More information

For a detailed example of connecting to OceanBase Database through OceanBase Connector/J, see Connect to OceanBase Database by using OceanBase Connector/J.