Detailed the technical principles of the structure framework in the Java library
The structural framework in the Java library is a technology that is often used in Java programming languages.It allows developers to quickly build complex applications by creating and configuration objects.This article will detail the technical principles of the structure framework in the Java library and explain it through the Java code example.
The core principle of the structure framework technology is to connect a variety of different components and objects by using the decorative mode.These components can be pre -defined in the class library, or the developer is customized.By combining these components, we can create flexible and highly configurable applications.
The structural framework in the Java class library is usually composed of the following key components:
1. Abstract class or interface: The structure frame usually defines an abstract base class or interface, which contains abstract methods for each step in the constructive process.These steps may include the creation, initialization, configuration and destruction of the object.
2. Specific implementation class: In order to use the structure framework, developers need to provide one or more specific implementation classes to implement the method defined in abstract classes or interfaces.These implementation classes are usually designed as insertable to facilitate extension and custom.
3. Configuration file: The structure framework usually uses a configuration file to describe the creation and configuration details of the object.This configuration file can be based on XML or other formats, and can contain the attributes, dependency relationships, and other necessary information of the object.Through this configuration file, developers can easily define the relationship between and organizational objects in the application.
4. Reflex: Constructing framework usually uses Java's reflection mechanism to achieve the creation and configuration of objects.By reflection, we can dynamically create objects at runtime, and call the object's method to set attributes and configurations.
The following is a simple example to illustrate the technical principles of the structure framework in the Java class library.Suppose we are building a simple application, which contains a CAR class and an Engine class.We hope to create and configure these objects through the structure framework.
First, we create an abstract class or interface to define the steps in the constructor.In this example, we create an abstract base class called Construction, which contains two abstract methods `create () and` Configure () `:
abstract class Constructible {
public abstract void create();
public abstract void configure();
}
Then, we create a specific implementation class CAR and Engine, which inherit the abstract class Constructure and implement the method:
class Car extends Constructible {
@Override
public void create() {
System.out.println("Creating car...");
}
@Override
public void configure() {
System.out.println("Configuring car...");
}
}
class Engine extends Constructible {
@Override
public void create() {
System.out.println("Creating engine...");
}
@Override
public void configure() {
System.out.println("Configuring engine...");
}
}
Next, we create a configuration file to describe the creation and configuration details of the object.In this example, we use the configuration file in the xml format `config.xml`:
<config>
<car>
<engine>
<create>Engine.create</create>
<configure>Engine.configure</configure>
</engine>
<create>Car.create</create>
<configure>Car.configure</configure>
</car>
</config>
Finally, we use the reflection mechanism to read the configuration file and create and configure the object:
public class Main {
public static void main(String[] args) {
// Read the configuration file
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse(new File("config.xml"));
// Create and configure objects
Node carNode = document.getElementsByTagName("car").item(0);
Constructible car = (Constructible) Class.forName(
carNode.getElementsByTagName("create").item(0).getTextContent())
.newInstance();
car.create();
NodeList engineNodes = carNode.getElementsByTagName("engine");
for (int i = 0; i < engineNodes.getLength(); i++) {
Constructible engine = (Constructible) Class.forName(
engineNodes.item(i).getElementsByTagName("create").item(0).getTextContent())
.newInstance();
engine.create();
car.configure();
engine.configure();
}
}
}
By running the above code, we can see the following output results:
Creating car...
Creating engine...
Configuring car...
Configuring engine...
Through this simple example, we can see the basic principles of constructing framework technology.By defining an abstract class or interface, and using specific implementation classes, configuration files, and reflection mechanisms, we can easily create and configure complex objects and components.The design pattern of this structure frame makes our applications more flexible and maintained.
