Oscache Error error while trying to flush writer

Struts2.3 + spring3 + hibernate3 Development
Now I want to use Oscache to improve the performance and find problems in use.
For example, use the struts2 tag
<Cache: cache time = "60" Scope = "session">
<S: Action name = "ztree. Action" executeresult = "false"/>
</Cache: cache>
The action function reads data from the database and reports an error.
Warn [http-8080-Processor5] actioncomponent: 122- Error while trying to flush writer
Java. Io. ioexception: Illegal to flush within a custom tag
At javax. servlet. jsp. tagext. bodycontent. Flush (bodycontent. Java: 79)
At com. opensymphony. webwork. components. actioncomponent. End (actioncomponent. Java: 120)
At com. opensymphony. webwork. Views. jsp. componenttagsupport. doendtag (componenttagsupport. Java: 21)
At org. Apache. JSPs. oscachedemo_jsp. _ jspx_meth_ww_action_0 (Org. Apache. jsp. oscachedemo_jsp: 232)
At org. Apache. jsp. oscachedemo_jsp. _ jspx_meth_cache_cache_0 (Org. Apache. jsp. oscachedemo_jsp: 178)

However, data can be retrieved from the same table.
Refresh the cache portion of the page within one minute.
Set flush = "false" to false.

<Cache: cache time = "60" Scope = "session">
<S: Action name = "ztree. Action" executeresult = "false" Flush = "false"/>
</Cache: cache>

Oscache Error error while trying to flush writer