Understand the core function and use of the Gerald Jorm framework in the Java class library
The Gerald Jorm framework is a framework that provides core functions in the Java class library. It is mainly used for the Object-Relational Mapping (ORM) and database operations.This article will introduce the core function of the Gerald Jorm framework and its purpose.
1. Object relationship mapping (ORM)
Object relationship mapping (ORM) is a technology that stores data in the way the method of the object model that stores the data in a relationship database and the object -oriented language -oriented programming language.The Gerald Jorm framework provides a set of simple and easy -to -use APIs, enabling developers to map the Java objects to the tables in the relational database, thereby achieving seamless integration between objects and databases.
The following is an example code that uses the Gerald Jorm framework for ORM:
// Create a POJO (PLAIN OLD JAVA OBJECT) class
public class User {
private int id;
private String name;
// omit other attributes and methods
// Use the mapping relationship between the annotation definition and the database table
@Column("user_id")
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
@Column("user_name")
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
// Use the Gerald Jorm framework in the application for the mapping of the object and the database table
public class Main {
public static void main(String[] args) {
// Create a Gerald Jorm session factory
SessionFactory sessionFactory = new SessionFactory();
// Get a session object
Session session = sessionFactory.openSession();
// Get a DAO object corresponding to a database table
UserDao userDao = session.getDao(UserDao.class);
// Create a new user object
User user = new User();
user.setId(1);
user.setName("John");
// Insert the user object into the database
userDao.insert(user);
// Find all user objects from the database
List<User> userList = userDao.selectAll();
// Print the query results
for (User u : userList) {
System.out.println(u.getId() + " - " + u.getName());
}
}
}
2. Database operation
In addition to the ORM function, the Gerald Jorm framework also provides a series of APIs for database operations to perform common addition, deletion, and investigation operations, and transaction management.Developers can easily use these APIs to easily interact with relational databases.
The following is an example code that uses the Gerald Jorm framework for database operations:
public class Main {
public static void main(String[] args) {
// Create a Gerald Jorm session factory
SessionFactory sessionFactory = new SessionFactory();
// Get a session object
Session session = sessionFactory.openSession();
// Execute the SQL statement
session.execute("CREATE TABLE IF NOT EXISTS user (id INT PRIMARY KEY, name VARCHAR(50))");
// Insert a record
session.execute("INSERT INTO user (id, name) VALUES (1, 'John')");
// update record
session.execute("UPDATE user SET name = 'Tom' WHERE id = 1");
// Delete Record
session.execute("DELETE FROM user WHERE id = 1");
// Execute transactions
session.beginTransaction();
try {
// Execute a series of database operations
session.execute("INSERT INTO user (id, name) VALUES (2, 'Alice')");
session.execute("INSERT INTO user (id, name) VALUES (3, 'Bob')");
// Submit a transaction
session.commit();
} catch (Exception e) {
// Roll back the transaction when it is abnormal
session.rollback();
e.printStackTrace();
}
}
}
Summary: Gerald Jorm framework is a Java class library that provides object -relationship mapping (ORM) and database operation functions.It helps developers to easily map the Java objects to the tables in the relational database, and provide a series of simple and easy -to -use APIs to perform common database operations.By using the Gerald Jorm framework, developers can perform database operations more efficiently to improve development efficiency and code quality.