CDI不工作

Question

它有一个servlet和一个JAX-RS资源POJO，两者都运行良好。接下来，我在与servlet和JAX-RS POJO相同的包中创建了一个类：

package com.example.test;

import java.util.logging.Logger;

import javax.enterprise.context.ApplicationScoped;
import javax.enterprise.inject.Produces;

@ApplicationScoped
public class Bean {

  @Produces @ApplicationScoped
  public static Bean produce () {
    return new Bean();
  }

  public Bean () {
    Logger.getGlobal().info("Bean()");
  }

}

package com.example.test;

import javax.annotation.Resource;
import javax.inject.Inject;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;

@Resource(name = "foo", type = Rest.class)
@Path("/rest")
public class Rest {

  @Inject Bean b;

  @GET
  @Produces("text/html")
  public String f () {
    return "<h1>rest</h1>";
  }
}

当我访问POJO的rest路径时，我在Glassfish日志中得到消息：

WARNING: StandardWrapperValve[com.younum.web.test.App]: Servlet.service() for servlet com.example.test.App threw exception
org.glassfish.hk2.api.UnsatisfiedDependencyException: There was no object available for injection at Injectee(requiredType=Bean,parent=Rest,qualifiers={}),position=-1,optional=false,self=false,unqualified=null,1573724652)

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.younum.web</groupId>
  <artifactId>test</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>
</project>

Answer 1

您需要将beans.xml文件放在META-INF文件夹中。默认情况下，部署项目时不启用或激活CDI。所以要激活它，我们需要beans.xml文件，它应该驻留在meta-inf文件夹下。

下面是beans.xml示例

<beans xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/beans_1_0.xsd">
</beans>