Question

跟进this SO thread，我的问题是我是否在做一些根本性的错误：

使用GlassFish 4.1，我正在尝试编写一个具有如下构造函数的MessageBodyReader：

package com.acme;

import javax.ws.rs.core.Context;
import javax.ws.rs.ext.Provider;
import javax.ws.rs.ext.Providers;
import javax.ws.rs.Consumes;

@Provider
@Consumes( "application/xml" )
public class MyMessageBodyReader implements MessageBodyReader<Object> {
   public MyMessageBodyReader(@Context Providers ps) {
      // try to do something with ps here
      // e.g. pass to a superclass constructor,
      // as required by the solution in the other thread
   }

   [...] // implemented interface methods
}

但无论我做什么周围的配置，我总是得到一系列这些例外：

2016-06-07T17:19:28.484+0200|WARN: The following warnings have been detected: WARNING: Unknown HK2 failure detected:
MultiException stack 1 of 1
org.jboss.weld.exceptions.CreationException: WELD-001530: Cannot produce an instance of class com.acme.MyMessageBodyReader.
    at org.jboss.weld.injection.producer.NonProducibleInjectionTarget.produce(NonProducibleInjectionTarget.java:55)
    at org.glassfish.jersey.gf.cdi.internal.CdiComponentProvider$CdiFactory$2.getInstance(CdiComponentProvider.java:242)
    at org.glassfish.jersey.gf.cdi.internal.CdiComponentProvider$CdiFactory.provide(CdiComponentProvider.java:189)
    [...]

接着是

WARNING: Unknown HK2 failure detected:
MultiException stack 1 of 2
org.jboss.weld.exceptions.CreationException: WELD-001530: Cannot produce an instance of class com.acme.MyMessageBodyReader.
    at org.jboss.weld.injection.producer.NonProducibleInjectionTarget.produce(NonProducibleInjectionTarget.java:55)
    at org.glassfish.jersey.gf.cdi.internal.CdiComponentProvider$CdiFactory$2.getInstance(CdiComponentProvider.java:242)
    at org.glassfish.jersey.gf.cdi.internal.CdiComponentProvider$CdiFactory.provide(CdiComponentProvider.java:189)
    [...]
MultiException stack 2 of 2
java.lang.IllegalStateException: Unable to perform operation: create on org.glassfish.jersey.message.internal.MessageBodyFactory
    at org.jvnet.hk2.internal.ClazzCreator.create(ClazzCreator.java:389)
    at org.jvnet.hk2.internal.SystemDescriptor.create(SystemDescriptor.java:461)
    at org.jvnet.hk2.internal.SingletonContext$1.compute(SingletonContext.java:114)
    [...]

我发现了几个将Providers注入构造函数的例子，而不是玻璃文件4.1附带的XmlRootElementJaxbProvider子类中的最小例子 - 毕竟，我想重用它们的类层次结构，因为它是在链接的线程中完成的。

提前感谢任何建议。

Answer 1

我无法解释异常的根本原因，但我遇到了同样的问题，当时并没有感觉像是钻研泽西源而已经比我已经拥有的更多了。

我最终懒得加载我的自定义MessageBodyReader / Writers，所以我可以将Providers注入包装器。它不漂亮但它有效。

有些事情：

@Provider
@Consumes( "application/xml" )
public class MyLazyMessageBodyReader implements MessageBodyReader<Object> {
  @Context
  private Providers ps;

  private MessageBodyReader<Object> reader;

  @Override
  public final Object readFrom(
          Class<Object> type,
          Type type1,
          Annotation[] antns,
          MediaType mt,
          MultivaluedMap<String, String> mm,
          InputStream in)
          throws IOException, WebApplicationException
  {
    return this.getLazyReader().readFrom(type, type1, antns, mt, mm, in);
  }

  private MessageBodyReader<Object> getLazyReader() {
    if (this.reader == null) {
      this.reader = new MyMessageBodyReader(this.ps);
    }
    return this.reader;
  }
}

public class MyMessageBodyReader implements MessageBodyReader<Object> {
   public MyMessageBodyReader(Providers ps) {
      // try to do something with ps here
      // e.g. pass to a superclass constructor,
      // as required by the solution in the other thread
   }

   [...] // implemented interface methods
}

使用@Context的Jersey构造函数注入不起作用

1 个答案: