CODEWITHSUNDEEP
javaspringurlclassloader
samitgaur
samitgaur

Reputation: 5661

How can I make Spring load classes from a given URL (for bean instantiation)?

Is there a way to tell Spring to load classes from a given URL while instantiating the beans? I need to load classes from a location that is not in the classpath. If I were using pure Java, I could use URLClassLoader but how can I achieve this in Spring? I am using Spring 3.0

Upvotes: 4

Views: 4109

Answers (2)

KeineSorgen
KeineSorgen

Reputation: 51

public class Main {

    public static void main(String[] args) throws Exception {  
        AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(AutodeployConfiguration.class);

        URL[] files = {
            new File("C:\\module1.jar").toURL(),
            new File("C:\\propertiesdirectory\\").toURL()
        };

        URLClassLoader plugin = new URLClassLoader(files, Main.class.getClassLoader());
        Thread.currentThread().setContextClassLoader(plugin);

        Class startclass = plugin.loadClass("de.module1.YourModule");
        ExternalModule start = (ExternalModule) startclass.newInstance();
        AnnotationConfigApplicationContext ivr = start.onDeploy(plugin, ctx);
    }
}


public class YourModule implements ExternalModule {

    @Override
    public AnnotationConfigApplicationContext onDeploy(ClassLoader classloader, GenericApplicationContext parent) {      
        AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext();
        applicationContext.setClassLoader(classloader);
        applicationContext.setParent(parent);
        applicationContext.register(ModuleConcreteConfiguration.class);
        applicationContext.refresh();


        // other code

        return applicationContext;
    }
}

Upvotes: 0

Dev
Dev

Reputation: 12206

All Spring classes that extend DefaultResourceLoader can have an explicit ClassLoader reference set (via DefaultResourceLoader.setClassLoader(ClassLoader).

AbstractApplicationContext happens to be one of those classes. So all ApplicationContext implementations that extend it (like ClassPathXmlApplicationContext and FileSystemXmlApplicationContext) can use an injected ClassLoader reference.

Upvotes: 6

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