Use Apache Velocity Engine to implement the template rendering in the Java class library

Apache Velocity Engine is an open source Java template engine that helps developers to easily generate template rendering.The engine is very popular and is widely used in template processing of various Java applications. It is very simple to implement template rendering in Java, just follow the following steps: 1. Import the dependency item of Apache Velocity Engine: First of all, you need to add the dependencies of the Apache-Velocity engine to the project dependency item so that the relevant class and methods can be used.You can import the following code to the Maven Pom.xml file to import the dependency item: <dependency> <groupId>org.apache.velocity</groupId> <artifactId>velocity-engine-core</artifactId> <version>2.2.1</version> </dependency> 2. Create the Velocity engine object: Create a Velocity engine object in the code, you can use the following code to create: import org.apache.velocity.app.VelocityEngine; import org.apache.velocity.Template; import org.apache.velocity.VelocityContext; VelocityEngine velocityEngine = new VelocityEngine(); velocityEngine.init(); 3. Load template: Load the template file with the Velocity engine object.The template can be a file or a string.The following code demonstrates how to load the template in the file: Template template = velocityEngine.getTemplate("path/to/template.vm"); 4. Create and fill in the context: Create Velocity context objects and fill in the required data, which will be used during the template rendering process.For example, the following code demonstrates how to add a variable called "name" to the context: VelocityContext context = new VelocityContext(); context.put ("name", "Zhang San"); 5. Rendering template: Use the filled context object for template rendering.The following code demonstrates how to render templates and print the results to the standard output: StringWriter writer = new StringWriter(); template.merge(context, writer); System.out.println(writer.toString()); This is the basic step of using Apache Velocity Engine to implement the template rendering in the Java class library.Developers can customize more complicated templates according to their needs and easily generate corresponding outputs through the Velocity engine.