Use the UJO ORM framework to achieve data persistence in the Java class library
Use the UJO ORM framework to achieve durable data
In Java development, data persistence is a very important concept.It refers to saving the data to the persistent storage medium (such as the database) so that the data can still be accessed and used after the program is closed.Common data persistence methods include relational databases, text files, and NOSQL databases.
UJO (Unified Java Object) is an ORM (object relationship mapping) framework. It maps the Java object to the table in the relationship database, providing a simple, fast and convenient method to achieve data persistence.In this article, we will introduce how to use the UJO ORM framework to achieve data persistence.
First, we need to configure the UJO ORM framework.We need to add Ujo ORM's jar files to the ClassPath of the Java project.You can download the latest jar files on the UJO official website.
Next, we need to configure a relationship database.The UJO ORM framework supports a variety of databases, including MySQL, Oracle, and SQLite.We need to provide database connection information, including URL, username and password.This information can be configured in the project configuration file.
Now, we can start writing Java code to achieve durable data.First, we need to create a Java class that will be mapped to the table in the database.We can use the annotations provided by UJO to specify the table name, list name and primary key.The following is an example class:
import org.springframework.orm.ujo.UjoFields;
import org.springframework.orm.ujo.UjoSaveable;
import org.springframework.orm.ujo.UjoTransaction;
@UjoSaveable(table = "users")
public class User {
@UjoFields("id")
private int id;
@UjoFields("name")
private String name;
public User() {
}
public User(String name) {
this.name = name;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
In the above example, we created a Java class called User and used the @ujosaveable annotation specifically to specify the UserS table in the database for mapping.We also use the @ujofields annotation specified ID field to map to the ID column in the table, and the name field is mapped to the name column.
Next, we can write code to operate the User object and save the data into the database.The following is an example code:
import org.springframework.orm.ujo.UjoCallback;
import org.springframework.orm.ujo.UjoManager;
public class Main {
public static void main(String[] args) {
User user1 = new User("John");
User user2 = new User("Alice");
// Save the object to the database
UjoManager.getInstance().doCallback(new UjoCallback<Boolean>() {
@Override
public Boolean call() throws Exception {
UjoTransaction tran = UjoManager.getInstance().createTransaction();
tran.insert(user1);
tran.insert(user2);
tran.commit();
return true;
}
});
// Load the object from the database
UjoManager.getInstance().doCallback(new UjoCallback<Boolean>() {
@Override
public Boolean call() throws Exception {
UjoTransaction tran = UjoManager.getInstance().createTransaction();
User loadedUser1 = tran.load(User.class, user1.getId());
User loadedUser2 = tran.load(User.class, user2.getId());
System.out.println(loadedUser1.getName());
System.out.println(loadedUser2.getName());
return true;
}
});
}
}
In the above examples, we first created two User objects and used Ujomanager to save them into the database.We then load these objects from the database with Ujomanager and print their names.
Through the above simple examples, we can see that the duration of data is very simple to use the UJO ORM framework.You only need to configure the UJO ORM framework and database connection information, and then use the annotations provided by UJO to map the Java class and database tables. Finally, UJOMANAGER can be used to operate the object and the database to achieve durable data.In actual development, we can configure and adjust the UJO ORM as needed to meet the needs of specific projects.
