Application of squeryl framework in Java Library: Getting Started Guide
Squeryl is a lightweight ORM (object relationship mapping) framework for the Java library, which provides a simple and powerful way to handle database operations.This article will provide you with an entry guide for the Squeryl framework, including a complete programming code and related configuration description.
1. Pre -requirements
Before starting to use squeryl, make sure you have completed the following preparations:
-Co Java JDK (Version 1.8 or higher)
-The database installation and configuration (this tutorial uses MySQL as an example)
2. Import squeryl dependencies
To use Squryl in the project, you need to add the following dependencies in the configuration file of the Maven or Gradle project:
// Maven dependence configuration
<dependency>
<groupId>org.squeryl</groupId>
<artifactId>squeryl_2.13</artifactId>
<version>0.9.10</version>
</dependency>
// Gradle dependency configuration
implementation 'org.squeryl:squeryl_2.13:0.9.10'
3. Create a database table
Before using Squeryl, you first need to create a database table for operation.In MySQL, you can use the following SQL statements to create a table called "Users":
sql
CREATE TABLE users (
id INT PRIMARY KEY AUTO_INCREMENT,
name VARCHAR(50),
age INT
);
4. Create a physical class
Next, you need to create a physical class that represents the "users" table.In this example, we will create a class called "User", which contains ID, name, and Age attributes, which correspond to columns corresponding to database tables.
import org.squeryl.annotations.Column;
public class User {
@Column("id")
private int id;
@Column("name")
private String name;
@Column("age")
private int age;
// Construct function, Getter, and Setter method omitted
}
Please note that we use squeryl's `@column` annotations to map the attributes and columns in the table.
5. Configure database connection
Before starting to use Squeryl, you need to configure database connections.In this example, we will use mysql database as an example.You can add the following configuration to the configuration file of the project:
import org.squeryl.Session;
import org.squeryl.SessionFactory;
import org.squeryl.adapters.H2Adapter;
public class DatabaseConfig {
private static final String DATABASE_DRIVER = "com.mysql.jdbc.Driver";
private static final String DATABASE_URL = "jdbc:mysql://localhost:3306/mydb";
private static final String DATABASE_USERNAME = "root";
private static final String DATABASE_PASSWORD = "password";
public static void configure() {
SessionFactory sessionFactory = new SessionFactoryBuilder()
.setAdapter(new MySQLAdapter())
.setUrl(DATABASE_URL)
.setUser(DATABASE_USERNAME)
.setPassword(DATABASE_PASSWORD)
.createSessionFactory();
SessionFactory.concreteFactory = sessionFactory;
}
}
In the above code, we use Squryl's sessionFactory to configure the database connection.Make sure that the URL, user name and password are replaced with the corresponding value.
6. Execute the database operation
Now, you are ready to use squeryl for database operations.Here are some common database operation examples:
import org.squeryl.Session;
import org.squeryl.SessionFactory;
import org.squeryl.Table;
import org.squeryl.adapters.H2Adapter;
import java.util.List;
public class Main {
public static void main(String[] args) {
// Configure database connection
DatabaseConfig.configure();
// Get the database meeting
Session session = SessionFactory.getSession();
// Get the USERS table
Table<User> users = session.table("users", User.class);
// Insert data
User user1 = new User("John Doe", 25);
users.insert(user1);
// Query data
List<User> userList = users.toList();
for (User user : userList) {
System.out.println(user.getName() + ", " + user.getAge());
}
// update data
User user2 = users.where(u -> u.getId() == 1).single();
user2.setAge(30);
users.update(user2);
// delete data
User user3 = users.where(u -> u.getId() == 1).single();
users.delete(user3);
// Close the database meeting
session.close();
}
}
In the above example, we first configured the database connection and then obtained the database.We can then use the table method to obtain the table object, and then insert, query, update, and delete operations.
Please note that after the database operation, we must close the session to release resources.
This is an entry guide for database operations using the Squeryl framework.Through the above steps, you should be able to start using Squryl for more complex database operations.Hope this article will help you!
