今天同事问我说，如何处理RECEIVE、VISIBLE的JMS消息？有点懵，之前从没有关注过消息的状态。Weblogic81中，我们是不能看到destination中的消息的，只能看到当前destination中，有多少message, 有多少pending的message。而92中，我们监控destination的时候，可以看到具体的message，而且message后面会跟一个state string。标题中说的RECEIVE、VISIBLE就是这个state string，其实state有很多，常见的也就是RECEIVE、VISIBLE。下面我们看看所有这些STATE在代码（MessageInfo.java）中的解释，

VISIBLE：Indicates that the message is visible on the destination.消息已经入列，等待被消费。

ORDERED：Indicates that the message belongs to a Unit of Order. 消息处于某个unit中。

DELAYED：Indicates that the message exists on the destination but is classified as pending because it has a scheduled delivery time or is delayed. 消息已经入列，但因为TimeToDeliver还没有到，直到TimeToDeliver，该消息才会变成VISIBLE。

RECEIVE：Indicates that the message exists on the destination but is classified as pending because it has been received but not acknowledged. The actual state may also include STATE_TRANSACTION if the receive operation was performed as part of a transaction.消息已经入列，且已经被DELIVER到某个CONSUMER，但CONSUMER的ACKNOWLEDGE还没有收到。可能是网络问题或客户端设为CLIENT_ACK模式。

SEND：Indicates that the message exists on the destination but is classified as pending because it is part of a send operation that is in progress. The actual state may also include STATE_TRANSACTION if the send operation was perfromed as part of a transaction.消息已经入列，且正在被DELIVER到CONSUMER端。

TRANSACTION：Indicates that the message exists on the destination but is classified as pending because it is part of a send or receive operation that is being performed as part of a global transaction.

PAUSED：Indicates that the message exists on the destination but is being held in a pending state because of a pause operation. 消息因为PAUSE被PENDING在DEST中。

REDELIVERY_COUNT_EXCEEDED：Indicates that the message has exceeded the redelivery count set for the destination and is no longer available for consumption. 消息反复REDELIVERY的上限已经到达，这样的消息不会被重发。

根据消息的状态，我们基本可以断定JMS消息相关问题的位置，从而调查可以做到有的放矢。[@more@]