如何从同一服务器上的另一个应用程序调用 EJB？

Question

我有 java SE 示例客户端，在桌面上运行（代码如下）。但是我已经访问了WebSphere，被称为EJB 部署。如何重写以下代码以在 WebSphere 上工作？（当我离开这段代码就像它是程序工作时一样，但我认为这可以做得更简单和清晰）

主要方法：

WSConn connection = new WSConn();
final Plan plan = connection.getPlanBean();
com.ibm.websphere.security.auth.WSSubject.doAs(connection.getSubject(), new java.security.PrivilegedAction<Object>() {
public Object run() {
try {
    // App logic
} catch (Throwable t) {
    System.err.println("PrivilegedAction - Error calling EJB: " + t);
t.printStackTrace();
   }
     return null;
  }
}); // end doAs

WSConn class:

public class WSConn {
    private static final String INITIAL_CONTEXT_FACTORY = "com.ibm.websphere.naming.WsnInitialContextFactory";
    private static final String JAAS_MODULE = "WSLogin";
    private static final String MODEL_EJB_NAME_LONG = "ejb/com/ibm/ModelHome";
    private static final String PLAN_EJB_NAME_LONG = "ejb/com/ibm/PlanHome";
    private Subject subject;
    private InitialContext initialContext;
    private String serverName;
    private String serverPort;
    private String uid;
    private String pwd;
    private String remoteServerName;
    private Model modelBean;
    private Plan planBean;
    public WSConn() {
        Properties props = new Properties();
        try {
            props.load(WSConn.class.getClassLoader().getResourceAsStream("WSConn.properties"));
        } catch (IOException e) {
            e.printStackTrace();
        }

        serverName = props.getProperty("WSConn.serverName");
        serverPort = props.getProperty("WSConn.serverPort");
        uid = props.getProperty("WSConn.userID");
        pwd = props.getProperty("WSConn.password");
        remoteServerName = props.getProperty("WSConn.remoteServerName");
    }

    private void init() {
        if (subject == null || initialContext == null) {
            subject = login();
        }
    }

    private Subject login() {

        Subject subject = null;
        try {
            LoginContext lc = null;

            // CRATE LOGIN CONTEXT
            Hashtable<String, String> env = new Hashtable<String, String>();
            env.put(Context.INITIAL_CONTEXT_FACTORY, INITIAL_CONTEXT_FACTORY);
            env.put(Context.PROVIDER_URL, "corbaloc:iiop:" + serverName + ":" + serverPort);

            initialContext = new InitialContext(env);

            // Just to test the connection
            initialContext.lookup("");

            lc = new LoginContext(JAAS_MODULE, new WSCallbackHandlerImpl(uid, pwd));
            lc.login();

            subject = lc.getSubject();


        } catch (javax.naming.NoPermissionException exc) {
            System.err.println("[WSConn] - Login Error: " + exc);

        } catch (Exception exc) {
            System.err.println("[WSConn] - Error: " + exc);
        }
        return subject;
    }

    public wModel getModelBean() {
        if (modelBean == null) {
            init();
            modelBean = (wModel) com.ibm.websphere.security.auth.WSSubject.doAs(subject,
                    new java.security.PrivilegedAction<wModel>() {
                        public wModel run() {
                            wModel session = null;
                            try {
                                Object o = initialContext.lookup(MODEL_EJB_NAME_LONG);
                                wModelHome home = (wModelHome) PortableRemoteObject.narrow(o, wModelHome.class);

                                if (home != null) {
                                    session = home.create(remoteServerName);
                                }

                            } catch (Exception exc) {
                                System.err.println("Error getting model bean: " + exc);
                            }
                            return session;
                        }
                    }); // end doAs
        }

        return modelBean;
    }

    public wPlan getPlanBean() {
        if (planBean == null) {
            init();
            planBean = (wPlan) com.ibm.websphere.security.auth.WSSubject.doAs(subject,
                    new java.security.PrivilegedAction<wPlan>() {
                        public wPlan run() {
                            wPlan session = null;
                            try {
                                Object o = initialContext.lookup(PLAN_EJB_NAME_LONG);
                                wPlanHome home = (wPlanHome) PortableRemoteObject.narrow(o, wPlanHome.class);

                                if (home != null) {
                                    session = home.create(remoteServerName);
                                }

                            } catch (Exception exc) {
                                System.err.println("Error getting plan bean: " + exc);
                            }
                            return session;
                        }
                    }); // end doAs
        }

        return planBean;
    }

    public Subject getSubject() {
        if (subject == null) {
            init();
        }

        return subject;
    }
}

Answer 1

如果您尝试从 POJO class 访问 EJB，那么没有什么比 lookup+narrow 更简单的了。但是，如果 POJO 包含在应用程序（EAR 或 WAR）中，那么您可以声明并查找 EJB 引用 (java:comp/ejb/myEJB)，然后容器将执行 narrow 而不是您的代码。如果您将代码更改为托管 class，如 servlet、另一个 EJB 或 CDI bean，那么您可以使用 @EJB 注入，然后您甚至不需要查找。

Answer 2

如另一个答案所示，classic 机制是查找和缩小主界面。

获取初始上下文

final InitialContext initialContext = new InitialContext();

通过 jndi 名称查找主页，指定完整的 jndi 名称

Object obj = initialContext.lookup("ejb/com/ibm/tws/conn/plan/ConnPlanHome");

或者您可以在 WAR 中创建引用并使用 java:comp/env/您的姓名

然后把首页缩小到首页界面class

ConnPlanHome planHome = (ConnPlanHome)PortableRemoteObject.narrow(obj, ConnPlanHome.class);

然后创建 EJB 远程接口

ConnPlan plan = planHome.create();

about 调用应该适用于分布式 IBM Workload Scheduler。对于 IBM Workload Scheduler z/OS，JNDI 名称和 class 名称不同：

final InitialContext initialContext = new InitialContext();
String engineName = "XXXX";
Object obj = initialContext.lookup("ejb/com/ibm/tws/zconn/plan/ZConnPlanHome");
ZConnPlanHome planHome = (ZConnPlanHome)PortableRemoteObject.narrow(obj, ZConnPlanHome.class);
ZConnPlan plan = planHome.create(engineName);

用户凭据从客户端传播到引擎，客户端需要进行身份验证，否则引擎将拒绝请求。

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