Servlet中ServletContext方法getNamedDispatcher() an...

獲取RequestDispatcher有三中方法

1.RequestDispatcher dispatch = request.getRequestDispatcher(arg);這裏的參數能夠是一個相對路徑或者是一個不定的資源(sp, servlet)

2.RequestDispatcher dispatch = getServletContext.getRequestDispatcher(arg)這裏的參數必須是一個絕對路徑RUL(已/開始),有效的servlet或者jsp.這裏的URL是在web.xml文件裏定義的,必須以/開始

3.RequestDispatcher dispatch = getServletContext.getNamedDispatcher("string"); 這裏的參數必須是一個servlet的名字.在web.xml定義

Example

1 NamedDispatcher

Returns a RequestDispatcher object that acts as a wrapper for the named servlet.

getNamedDispatcher(String) method takes the name of the Servlet as parameter which is declared via Deployment descriptor. Example: Deployment Descriptor

<servlet>
    <servlet-name>FirstServlet</servlet-name>
    <servlet-class>com.example.ServletExample</servlet-class>
</servlet>

RequestDispatcher dispatch = request.getNamedDispatcher(?FirstServlet?);
dispatch.forward(request, response);

2.

RequestDispatcher

RequestDispatcher dispatch = request.getRequestDispatcher("/tes");

<servlet-mapping>
    <servlet-name>Test</servlet-name>
    <url-pattern>/tes</url-pattern>
</servlet-mapping>

3.

RequestDispatcher dispatch = request.getRequestDispatcher("/TestJspOne.jsp");