Logic: equal, logic: present usage

Logic: equal, logic: present usage

1.

<Logic: equal value = "A" name = "documentcontent"> display </logic: equal>

 

<Logic: equal name = "deliverproveform" property = "useraction" value = "CREATE">

If the value of the attribute useraction in deliverproveform is equal to create, execute this operation.

</Logic: equal>

2. <logic: present name = "tipmsg"> If tipmsg is set in your action, it will be executed here. For example, request. setattribute ("tipmsg", "prompt message") or session. setattribute ("tipmsg", "prompt message") <Bean: write name = "tipmsg"/> </logic: Present>

 

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Use of label <logic: Present>

Request. getsession (). setattribute ("pagebean", pagebean );

Request. setattribute ("result", pagebean. getobjlist ());

 

In JSP:

<Logic: present name = "result">

<Logic: iterate id = "book" name = "result">

<Logic: present name = "book">

<Tr>

<TD> <Bean: write name = "book" property = "name"/> </TD>

<TD> <Bean: write name = "book" property = "author"/> </TD>

<TD> <Bean: write name = "book" property = "price"/> </TD>

</Tr>

</Logic: Present>

</Logic: iterate>

</Logic: Present>

<Logic: present name = "result" Scope = "session">

Here there is a scope attribute that may be request, session, etc. name refers to an object, which may be a JavaBean or a collection object. The whole meaning is in the scope (Session, query whether the name (an object) exists in the request range, which is equivalent to an IF () statement.