java - JBoss7 : loader constraint violation with ReastEasy and httpclient with custom HttpRequestInterceptor

Question

我在带有 JBoss-7.1.1-Final 的 @Named @ViewScoped Bean 中使用 RestEasy 客户端框架，通过自定义 HttpRequestInterceptor 从 REST 服务检索数据>:

RegisterBuiltin.register(ResteasyProviderFactory.getInstance());

DefaultHttpClient httpClient = new DefaultHttpClient();
httpClient.addRequestInterceptor(new PreemptiveAuthInterceptor("test","test"), 0);

ClientExecutor clientExecutor = new ApacheHttpClient4Executor(httpClient); //<---

//The error occurs above, the code below is only for completeness
MyRest rest = ProxyFactory.create(MyRest.class,
                                    "http://localhost:8080/rest",clientExecutor);

这在独立的客户端应用程序中工作正常(当我删除 ClientExecutor 时也可以，但我需要它来验证 REST 服务)。该 bean 位于 EAR 内的 WAR 模块中，resteasy 的依赖层次结构解析为以下内容:

WAR 或EAR 中没有httpclient 或httpcore。在 Bean 内部，我得到以下异常:

java.lang.NoClassDefFoundError: org/apache/http/HttpRequestInterceptor

似乎很简单(尽管我对 resteasy 包装感到疑惑)并且我添加了 org.apache.httpcomponents:httpclient 和 compile 范围:

不，我得到他以下异常:

java.lang.LinkageError: loader constraint violation: when resolving method   
  "org.jboss.resteasy.client.core.executors.ApacheHttpClient4Executor.<init>    
  (Lorg/apache/http/client/HttpClient;)V"
  the class loader (instance of org/jboss/modules/ModuleClassLoader)
      of the current class, my/TestBean, and
  the class loader (instance of org/jboss/modules/ModuleClassLoader)
      for resolved class, 
  org/jboss/resteasy/client/core/executors/ApacheHttpClient4Executor,
  have different Class objects for the type org/apache/http/client/HttpClient
  used in the signature my.TestBean.init(TestBean.java:65)

更新 要重现此问题，您不需要 REST 接口(interface)，错误发生在实例化 ApacheHttpClient4Executor 时，但您可能需要自定义 PreemptiveAuthInterceptor:

public class PreemptiveAuthInterceptor implements HttpRequestInterceptor
{
  private String username;
  private String password;

  public PreemptiveAuthInterceptor(String username, String password)
  {
    this.username=username;
    this.password=password;
  }

  @Override
  public void process(org.apache.http.HttpRequest request, HttpContext context) throws HttpException, IOException
  {
    AuthState authState = (AuthState) context.getAttribute(ClientContext.TARGET_AUTH_STATE);

    authState.setAuthScope(org.apache.http.auth.AuthScope.ANY);
    authState.setCredentials(new UsernamePasswordCredentials(username,password));
    authState.setAuthScheme(new BasicScheme());

  }
}

Answer 1

为避免在 JBoss 上部署应用程序时出现链接错误，请在 JBoss 安装的模块文件夹中配置模块 org.apache.httpcomponents，但避免包含 JAR来自 HttpComponents 和你的应用程序:

1. 将来自 HttpComponents 的所需 JAR 放在 modules/org/apache/httpcomponents/main 中。
2. 在此目录的 module.xml 中列出这些 JAR。
3. 将 Dependencies: org.apache.httpcomponents 添加到组件的 MANIFEST.MF。

请注意，步骤 1 和 2 中引用的模块已经存在。但是，您可能希望包括其他 JARS(例如 httpclient-cache-x.y.z.jar)或不同版本。

在您的开发环境中解析类是另一回事。