onlyrac报错

请教下，Flink里面把流注册为表: tableEnv.registerDataStream("mytable", mystream ....) 这里的流 mystream 貌似必须是append only流，不能是retraction流。这是为什么？如果是retraction流，报错Table is not an append-only table. Use the toRetractStream() in order to handle add and retract messages.

Myeclipse中java web.xml报错cvc-complex-type.2.3: Element 'web-app' cannot have character [children], because the type's content type is element- only.