Question

我有一个简单的EJB，当我通过我的独立客户端运行它时，每件事情都运行良好，但是一旦我添加了一个拦截器，EJB中的@PostConstruct就会停止工作：

包拦截器;

public class LogInterceptor {

@PostConstruct
public void init(InvocationContext context) {
    System.out.println(new Date().toString() +" Entered interceptor");
}

@PreDestroy
public void aboutToBeRemoved(InvocationContext context) {
    System.out.println(new Date().toString() + " Leaving interceptor");
}

@AroundInvoke
public Object gettingToBusiness(InvocationContext context) {

    String methodName = context.getMethod().getName();
    System.out.println("The method name is: " +methodName);

    if (methodName.equals("add")) {

    }
    try {
        return context.proceed();
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}


}

我的测试客户：

public class Test {

public static void main(String[] args){
    InitialContext ctx=getInitialContext();
    ListRemote stub=null;
    try {
        stub = (ListRemote)ctx.lookup("ejb:/Lab12/ListEJB!interceptor.ListRemote?stateful");
    } catch (NamingException e) {
        System.out.println("Lookup Failed");
        e.printStackTrace();
    }
    System.out.println("Adding data");
    stub.add("Hello");
    stub.add("-");
    stub.add("World");
    stub.add("!!!");
    System.out.println("Getting data :");
    for(Object o:stub.getAll()){
        System.out.print(o+" ");
    }
    System.out.println("Removing '-' element");
    stub.remove(1);
    System.out.println("Getting data again:");
    for(Object o:stub.getAll()){
        System.out.print(o+" ");
    }
    stub.destroy();
}

public static InitialContext getInitialContext(){
    Properties properties = new Properties();
    properties.put(Context.URL_PKG_PREFIXES , "org.jboss.ejb.client.naming");
            try {
        return new InitialContext(properties);
    } catch (NamingException e) {
        System.out.println("Cannot generate InitialContext");
        e.printStackTrace();
    }
    return null;
}
}

我的EJB：

@Stateful(name="ListEJB")
@Interceptors({LogInterceptor.class})
public class ListBean implements ListRemote{
private ArrayList<Serializable> list;

@PostConstruct
public void init(){
    System.out.println("In it init ---------------------------------------------------");
    list=new ArrayList<Serializable>();
}
public void add(Serializable object){
    System.out.println("Currently in the list is: " +list);

    System.out.println("The object is: " +object);
    list.add(object);
    System.out.println("Added");
}
public Serializable get(int index){
    return list.get(index);
}
public void remove(int index){
    list.remove(index);
}
public Object[] getAll(){
    return list.toArray();
}
@Remove
public void destroy(){
    list=null;
}

}

为什么它会禁用我的EJB @PostConstruct？

Answer 1

在此代码中：

@PostConstruct
public void init(InvocationContext context) {
    System.out.println(new Date().toString() +" Entered interceptor");
}

您正在拦截原始EJB的PostConstruct并且不允许它通过。如果要将其传递给目标EJB，则需要调用proceed：

@PostConstruct
public void init(InvocationContext context) {
    System.out.println(new Date().toString() +" Entered interceptor");
    context.proceed();
}

同样适用于PreDestroy。基本上它适用于所有截获的方法。请参阅EJB3 specification，第12.5节（第287页）：

拦截器方法必须始终调用InvocationContext.proceed（）或否后续的拦截器方法或bean业务方法或生命周期将调用回调方法。

为什么@PostConstruct不起作用？

1 个答案: