Detailed explanation of the technical principles of the J2EE connector architecture in the Java class library
J2EE (Java 2 Platform, Enterprise Edition) connector architecture is a technical specification for developing enterprise applications.It provides a standard method that enables Java applications to communicate with the enterprise information system (EIS), such as databases, message queues and corporate resource plans (ERP) systems.The connector architecture defines a set of APIs and protocols for reliable, secure, and efficient communication between Java applications and EIS.
The core of the connector architecture is connector, which is a middleware. By providing a standardized communication interface, the Java application can access and operate EIS.The connector is responsible for processing the communication details with EIS, such as establishing connection, sending requests and receiving response.
The connector architecture is based on the following key concepts and technical principles:
1. Connector specifications (Connector Specification): The connector specifies the behavior and functions of the connector, including the configuration, deployment and operation requirements of the connector.It also defines the interface protocol between the connector and the Java application, as well as support for affairs and security.
2. Connection Points: The connection point is an interface that communicates between the connector and the Java application.The Java application sends a request to the connector through the connection point and receives the response returned by the connector.The connection point can be local (in the same Java virtual machine) or remote (between different Java virtual machines or servers).
3. Connection Factory: Connect the factory is an API provided by the connector to create and manage the connection point.By connecting the factory, the Java application can get the connection point instance and set the configuration parameter of the connector.Connecting the factory also handle the life cycle management of the connection point, including the creation, destroying and reusing.
The following is a simple example to demonstrate how to use the connecter architecture to communicate with the database:
import javax.resource.cci.Connection;
import javax.resource.cci.ConnectionFactory;
import javax.resource.cci.ConnectionSpec;
import javax.resource.cci.Record;
import javax.resource.cci.ResourceAdapter;
import javax.resource.cci.ResultSet;
public class J2EEConnectorExample {
public static void main(String[] args) {
// Get the connection factory
ConnectionFactory connectionFactory = getConnectionFactory();
// Create a connection point
Connection connection = connectionFactory.getConnection();
// Create SQL query statements
String query = "SELECT * FROM users";
// Execute the query and get the result set
ResultSet resultSet = connection.execute(query);
// Traversing results set and printing data
while (resultSet.next()) {
String username = resultSet.getString("username");
String email = resultSet.getString("email");
System.out.println("Username: " + username + ", Email: " + email);
}
// Turn off the connection
connection.close();
}
private static ConnectionFactory getConnectionFactory() {
// Get the implementation class connected to the factory
ResourceAdapter resourceAdapter = getResourceAdapter();
// Create a connection factory
ConnectionFactory connectionFactory = resourceAdapter.getConnectionFactory();
// Set connection parameters
ConnectionSpec connectionSpec = getConnectionSpec();
connectionFactory.setConnectionSpec(connectionSpec);
return connectionFactory;
}
private static ResourceAdapter getResourceAdapter() {
// Create and configure the resource adapter
ResourceAdapter resourceAdapter = new MyDatabaseResourceAdapter();
// ... Configure the relevant attributes of the resource adapter
return resourceAdapter;
}
private static ConnectionSpec getConnectionSpec() {
// Create and configure connection parameters
ConnectionSpec connectionSpec = new MyDatabaseConnectionSpec();
// ... Configure the related attributes of the connection parameter
return connectionSpec;
}
}
class MyDatabaseResourceAdapter implements ResourceAdapter {
public ConnectionFactory getConnectionFactory() {
// Return to connect to the factory instance
return new MyDatabaseConnectionFactory();
}
// ... Implement other interface methods
}
class MyDatabaseConnectionFactory implements ConnectionFactory {
public Connection getConnection() {
// Return to the connection point instance
return new MyDatabaseConnection();
}
// ... Implement other interface methods
}
class MyDatabaseConnection implements Connection {
public ResultSet execute(String query) {
// Execute the query and return the result set
// ... the actual database query operation
}
// ... Implement other interface methods
}
class MyDatabaseConnectionSpec implements ConnectionSpec {
// ... Configure the related attributes of the connection parameter
}
In the above example, we created a Java application based on the connecter architecture to communicate with the database through the connector.First, we obtain instances connecting the factory and set the connection parameters.Then, get the connection point by connecting to the factory, execute the database query, and obtain the results set.Finally, we traversed the results set and print the data to the console.In this example, `MyDataBaseReSourceAdapter`, MyDataBaseConnectionFactory` and` MyDataBaseConnection` are custom connectors components.
In short, the J2EE connector architecture provides a standardized method that enables Java applications to communicate reliable, secure and efficiently with the corporate information system.With the help of the connector architecture, developers can easily integrate various EISs and realize data interaction with them.
