Know the how to use the Apache Groovy script in the Java library
Apache Groovy is a dynamic script language based on the Java platform. It is closely integrated with Java and can be used directly in the Java code.This article discusses how to use the Apache Groovy script in the Java class library and provide the corresponding Java code example.
First, make sure that Apache Groovy's dependence has been introduced in the project.You can use Maven or Gradle and other construction tools to add the following dependencies to the configuration file of the project:
<!-Maven dependence->
<dependency>
<groupId>org.codehaus.groovy</groupId>
<artifactId>groovy-all</artifactId>
<version>3.0.7</version>
</dependency>
groovy
// Gradle dependencies
implementation 'org.codehaus.groovy:groovy-all:3.0.7'
Next, let's see a simple example to demonstrate the use of the Groovy script in the Java library.Suppose we have a Java library, which contains a class called Mathutils, which has a static method called ADD to add two numbers.
First of all, create a Groovy script file in the project, named "Calculation. Groovy", and write the following Groovy code:
groovy
class Calculation {
static int multiply(int a, int b) {
return a * b
}
}
Then, the Multiply method of the Groovy script is called in the mathutils class in the Java library. The example is as follows:
import groovy.lang.GroovyClassLoader;
import groovy.lang.GroovyObject;
import groovy.lang.GroovyRuntimeException;
public class MathUtils {
public static void main(String[] args) {
GroovyClassLoader groovyClassLoader = new GroovyClassLoader();
try {
Class<?> groovyClass = groovyClassLoader.parseClass(new File("Calculation.groovy"));
GroovyObject groovyObject = (GroovyObject) groovyClass.getDeclaredConstructor().newInstance();
int result = (int) groovyObject.invokeMethod("multiply", 5, 10);
System.out.println("Multiply result: " + result);
} catch (IllegalAccessException | InstantiationException |
NoSuchMethodException | InvocationTargetException |
GroovyRuntimeException | IOException e) {
e.printStackTrace();
}
}
public static int add(int a, int b) {
return a + b;
}
}
In the above example, we created a GroovyClassLoader object, and then used it to load and parse the Groovy script file.Next, by calling the InvokeMethod method, we can call the Multiply method of the Groovy script in Java to pass the parameters and get the return value.
In addition, we also provide a Java static method called ADD in the Mathutils class to demonstrate the mixed use of Java and Groovy code.
In summary, this article discusses the basic method of using Apache Groovy scripts in the Java class library and provides an example.Through in -depth understanding of Groovy's flexibility and close integration with Java, we can better use the Groovy script to expand and enhance the functions of Java applications.
