The application and practice of the Gerald Jorm framework in the Java library
The application and practice of the Gerald Jorm framework in the Java library
Introduction:
Gerald Jorm (Java Object Relation Mapping) is an open source Java framework for mapping between database and Java objects.It provides a simple and easy -to -use way to handle the database's persistence operation, enabling developers to operate the database more easily, and reduce development complexity and maintenance costs.
Application and practice:
1. Object persistence: Gerald Jorm can persist Java objects into the database.By using annotations or xml configuration files, developers can define the mapping relationship between objects and database tables.The following is an example:
@JormEntity(table = "students")
public class Student {
@JormId(column = "id")
private int id;
@JormColumn(column = "name")
private String name;
// omit other attributes and methods
}
// Use in the application
Student student = new Student();
student.setId(1);
student.setName("Tom");
JormSession session = JormSessionFactory.openSession();
session.save(student);
2. Query data: Use Gerald Jorm to easily perform the database query operation.Developers can use the object query language (OQL) to write query statements without writing SQL statements directly.The following is an example:
JormSession session = JormSessionFactory.openSession();
List<Student> students = session.createQuery("SELECT s FROM Student s WHERE s.name = 'Tom'").getResultList();
for (Student student : students) {
System.out.println(student.getName());
}
3. Update and delete data: With Gerald Jorm, developers can easily perform update and delete operations.By setting a new value on the object, and then calling the `update` and` delete` method of Session to complete the corresponding operation of the database.The following is an example:
JormSession session = JormSessionFactory.openSession();
Student student = session.get(Student.class, 1);
student.setName("Jerry");
session.update(student);
// delete data
session.delete(student);
4. Affairs management: Gerald Jorm also provides the ability of transaction management.Developers can achieve transaction management by using the `@jormtransaction` annotation or manually call the session 'begintraction` and` Committransactions' to achieve transaction management.The following is an example:
@JormTransaction
public void updateStudentName(int id, String name) {
JormSession session = JormSessionFactory.openSession();
Student student = session.get(Student.class, id);
student.setName(name);
session.update(student);
}
Summarize:
The Gerald Jorm framework is widely used in the Java library. By simplifying the mapping relationship between database operations and Java objects, developers can operate databases more efficiently.It provides the function of convenient object persistence, query, update, and deleting data, and supports transaction management.Through this powerful framework, developers can save a lot of development time and energy, and improve the maintenance of code.
