JSP study Note 1

1.

<% --... -- %> Hide comments

<! --... --> Dynamic annotation, displayed in the document, and the JSP expression can be interpreted inside the comment;

2.

% Tomcat_home %/CONF/server. xml

<Context Path = "/book"

Docbase = "webapps/book">

</Context>

3.

Declaration <%! Declaration (s) %> has class, object scope

Expression <% = expression %> has a method scope. (An expression cannot end with a; sign)

The script applet <% scriptlet %> can also declare a variable here, and the variable has a method scope.

Considering the thread-safe relationship, local variables are declared first in the expression, and the declaration is usually used to declare Read-Only variables (final)

4.

Synchronize variables in JSP declarations or use a page command to set the isthreadsafe attribute to false

<% Synchronized (this ){

If (..){}

}

%>

5.

The difference between servletrequest. getrequestdispatcher andServletContext.getRequestDispatcher(java.lang.String)Is that this method can take a relative path.

6.

Getmoduleconfig (). findforwardconfig (string)

Response. senderror (httpservletresponse. SC _bad_request, getinternal (). getmessage ("noauthorized, mapping. getpath ()));

There are two ways to switch between sub-application modules. 1. Global or local <forward> element 2. Switchaction