CDI是否适用于常规Java应用程序？ [英] Does CDI work for regular Java application?

问题描述

我有三个类的简单maven项目。在我的 META-INF 中，我有空的 beans.xml 。每次我运行我的 Main.java 我得到一个 NullPointerException 。

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)

我想要完成的是超出范围CDI应该做什么？

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

Hello.java

Hello.java

package hom;
import javax.enterprise.inject.Default;

@Default
public class Hello {
   public String hello() {
      return "Hello ";
   }
}

World.java

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

Main.java

package hom;
public class Main {
   public static void main(String[] args) {
      World helloWorld = new World();
      System.out.println(helloWord.helloWorld());
   }
}

推荐答案

它可以在独立应用程序中使用CDI。

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();

您还需要焊接依赖。

<dependency>
    <groupId>org.jboss.weld.se</groupId>
    <artifactId>weld-se-core</artifactId>
    <version>2.2.4.Final</version>
</dependency>

参见焊接文档。

这篇关于CDI是否适用于常规Java应用程序？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！