我的事件属性中有一个元素可以为null的列表。我想创建一个ldap字符串来匹配空元素。
考虑以下工作示例：

private final BundleContext context = FrameworkUtil.getBundle(LdapTest.class).getBundleContext();
private final EventAdmin eventAdmin = this.context.getService(this.context.getServiceReference(EventAdmin.class));

@Test
public void test() throws Exception {
    final String value = "test";

    // register a listener

    final Dictionary<String, Object> serviceProperties = new Hashtable<>();
    serviceProperties.put(EventConstants.EVENT_TOPIC, new String[] { "myTopic" });
    serviceProperties.put(EventConstants.EVENT_FILTER, "(myProperty=" + value + ")");

    final boolean[] called = { false };
    final ServiceRegistration<EventHandler> listener = this.context.
            registerService(EventHandler.class, e -> called[0] = true, serviceProperties);

    // fire event

    Assert.assertFalse(called[0]);
    final Map<String, Object> eventProperties = new HashMap<>();
    eventProperties.put("myProperty", Arrays.asList(value));

    this.eventAdmin.sendEvent(new Event("myTopic", eventProperties));
    Assert.assertTrue(called[0]);

    listener.unregister();
}

现在如果我开始 value = null ，什么是 EVENT_FILTER 要让考试重新开始吗？
“我试过了” (!myProperty=*) “和” (!(myProperty=*)) ，但它不起作用。