UJO ORM framework and its technical principles in the Java class library analysis

UJO ORM framework and its technical principles in the Java class library analysis In Java application development, ORM (object relationship mapping) is a common technology. It combines relational databases with object -oriented programming language, so that developers can operate databases in an object -oriented manner.The UJO ORM framework is an important Java class library that provides a powerful ORM function. This article will analyze the technical principles of the UJO ORM framework. 1. Overview of UJO ORM Framework The UJO ORM framework is an ORM tool based on the Java reflection mechanism and annotation. It is encapsulated on the basis of the JDBC (Java database connection) to simplify the interactive operation with the database.The UJO ORM framework provides easy -to -use APIs, allowing developers to quickly perform database operations while maintaining good maintenance and scalability. Second, the core principle of the UJO ORM framework 1. The mapping of the physical class The UJO ORM framework maps the Java entity class and the table in the database by annotation.Developers can use @Entity annotations to identify a class as a physical class, and use the @Table annotation to specify the corresponding relationship between the physical class and the database table.In addition, @Column annotations can be used to specify the mapping relationship between the attributes in the physical class and the field in the database table. The example code is as follows: @Entity @Table(name = "user") public class User { @Id @Column(name = "id") private int id; @Column(name = "username") private String username; // getter and setter methods } 2. Database operation installation The UJO ORM framework encapsulates common database operations, such as adding, deletion, modification, etc., so that developers can call database operations through simple APIs.Developers can use the EntityManager class to manage the physical class. Through this method, they can create, update, delete physical objects, and perform query operations. The example code is as follows: // Create EntityManager object EntityManager entityManager = new EntityManager(); // Create physical objects User user = new User(); user.setId(1); user.setUsername("John"); // Insert the entity object entityManager.persist(user); // Update the physical object user.setUsername("John Smith"); entityManager.update(user); // Delete the physical object entityManager.remove(user); // Query physical object User retrievedUser = entityManager.find(User.class, 1); 3. Affairs management The UJO ORM framework also provides the function of transaction management. Developers can use annotations to identify methods that need to be managed.By adding @transactional annotations to the method, the UJO ORM framework will automatically manage this method to ensure the consistency and integrity of the data. The example code is as follows: @Transactional public void updateUser(User user) { // Update user information entityManager.update(user); // Update other related operations // ... } Third, the advantage of the UJO ORM framework 1. Simplify database operation: The UJO ORM framework encapsulates common database operations, simplifies the interaction with the database, and developers do not need to write tedious SQL statements. 2. Improve development efficiency: The UJO ORM framework provides easy -to -use APIs. Developers can quickly perform database operations to improve development efficiency. 3. Provide transaction management: UJO ORM framework supports transaction management, ensuring the consistency and integrity of data. 4. Strong expansion: The UJO ORM framework is based on the Java reflection mechanism and annotation. It has good expansion. Developers can customize the annotation and expansion framework function. In summary, the UJO ORM framework is a powerful Java class library that provides simplified database operation and reliable transaction management functions, enabling developers to develop database development more efficiently.