cdi java,CDI是否适用于常规Java应用程序？

I have simple maven project with three classes. In my META-INF I have my empty beans.xml. Everytime I run my Main.java I get a NullPointerException.

Exception in thread "main" java.lang.NullPointerException

at hom.World.helloWorld(World.java:12)

at hom.Main.main(Main.java:6)

Is what I'm trying to accomplish is way out of scope of what CDI is suppose to do?

Hello.java

package hom;

import javax.enterprise.inject.Default;

@Default

public class Hello {

public String hello() {

return "Hello ";

}

}

World.java

package hom;

import javax.enterprise.inject.Default;

import javax.inject.Inject;

@Default

public class World {

@Inject

Hello hello;

public String helloWorld() {

return hello.hello() + "World!";

}

}

Main.java

package hom;

public class Main {

public static void main(String[] args) {

World helloWorld = new World();

System.out.println(helloWord.helloWorld());

}

}

解决方案

It is possible to use CDI in a standalone application.

Weld weld = new Weld();

WeldContainer container = weld.initialize();

World helloWorld = container.instance().select(World.class).get();

System.out.println(helloWorld.helloWorld());

weld.shutdown();

You will also need the weld-se dependency.

org.jboss.weld.se

weld-se-core

2.2.4.Final

See also Weld documentation on the subject.