Introduction to the technical principle of the "Phantom" framework in the Java class library
The phantom framework is a Java class library that supports the mapping relationship between the code and the database by providing a set of technical principles.It is automated by mapping the database table structure to the Java class and provided CRUD (Create, Read, Update, Delete) operation.
The technical principles of the phantom frame mainly include the following aspects:
1. Object -relationship mapping (ORM): The phantom framework defines the mapping relationship between the Java class and the database table by annotating or configuration files.It automatically generates the physical class corresponding to the database table based on these mapping relationships.
2. Database connection pool: Phantom frame uses a database connection pool to manage the connection with the database.A certain number of database connections are maintained in the connection pool to improve system performance by reusing these connections.
3. Lazy loading: The Phantom Frame supports the lazy loading mechanism, that is, you can query the database only when the data object is needed.This can avoid unnecessary database queries and improve system performance and response speed.
4. Affairs management: The phantom framework provides a simple and powerful transaction management mechanism through encapsulating JDBC's transaction management function.It can ensure that multiple operations in one transaction are either successful or all fails to ensure the consistency and integrity of the data.
The following is a simple example that shows how to use the phantom framework for database operations:
First, define a Java class, such as user:
public class User {
private int id;
private String name;
// Eliminate the constructor, Getter, and Setter method
@Override
public String toString() {
return "User{" +
"id=" + id +
", name='" + name + '\'' +
'}';
}
}
Then, use the phantom framework for CRUD operation:
import org.jooq.DSLContext;
import org.jooq.impl.DSL;
import java.sql.Connection;
import java.sql.DriverManager;
import static jooq.tables.Users.USERS;
public class Main {
public static void main(String[] args) {
// Create a database connection
String url = "jdbc:mysql://localhost:3306/mydb";
String username = "root";
String password = "password";
try (Connection connection = DriverManager.getConnection(url, username, password)) {
// Create DSLContext objects
DSLContext create = DSL.using(connection);
// Insert data
User user = new User(1, "John");
create.insertInto(USERS, USERS.ID, USERS.NAME)
.values(user.getId(), user.getName())
.execute();
// Query data
User result = create.select()
.from(USERS)
.where(USERS.ID.eq(user.getId()))
.fetchOneInto(User.class);
System.out.println(result);
// update data
user.setName("Jack");
create.update(USERS)
.set(USERS.NAME, user.getName())
.where(USERS.ID.eq(user.getId()))
.execute();
// delete data
create.deleteFrom(USERS)
.where(USERS.ID.eq(user.getId()))
.execute();
} catch (Exception e) {
e.printStackTrace();
}
}
}
Through the phantom frame, it can simplify the operation of the database, reduce the workload of manual writing SQL statements, and improve development efficiency and code maintenance.
