WAS v8.5 > Migrate, coexist, and interoperate > Migrating web applications > Migrating web application components

Migrating web application components from WAS v5.x

Migration of web applications deployed in previous versions of WebSphere Application Server is usually not necessary. Versions 2.2 and later of the Java Servlet specification and versions 1.2 and 1.4 of the JSP specifications are still supported unless the behavior was changed in the Servlet 3.0 or JSP 2.1 specifications. These changes are generally available in more detail in their corresponding specification.

Servlet migration might be a concern if the application:

• Implements a WAS internal servlet to bypass a WAS Version 4.x single application path restriction
• Extends a PageListServlet that relies on configuration information in the servlet configuration XML file
• Calls the response.sendRedirect method for a servlet using the encodeRedirectURL function or starting within a non-context root
• Depends on a default Content-Type response header being set or the behavior of a setContentType call after a getWriter call is made. The behavior is set by WAS version level using the web container custom property com.ibm.ws.webcontainer.contenttypecompatibility with a value of V4, V5, V6. or V7. The behavior for each version is described below.

  Web container custom properties.. Describes the version behavior for each version.

  	Version 4	v5	v6	v7
  Default Content-Type	text/html	text/html; charset= <default_ encoding>	none	none
  Append Charset on getWriter if the property does not exist on Content-Type Example: response.setCharacterEncoding("UTF-8"); response.setContentType("text/xml"); response.getWriter();	text/html	text/html	text/xml; charset=UTF-8	text/xml; charset=UTF-8
  Remove charset from the Content-Type property if the setContentType property is called after getWriter with a ";charset=" portion Example: setContentType("text/html;charset=ISO-8859-7"); getWriter(); setContentType("text/xml;charset=UTF-8");	text/html	text/html	text/html	text/xml; charset=ISO-8859-7

JSP migration might be a concern if the application references JSP page implementation classes in unnamed packages, or if you install WAS Version 4.x EAR files (deployed in Version 4.x with the JSP Precompile option), in v5.x. You need to recompile all JSP pages when migrating from WAS v5.x.

For IBM extension and binding files, the .xmi or .xml file name extension is different depending on whether you are using a pre-Java EE 5 application or module or a Java EE 5 or later application or module. An IBM extension or binding file is named ibm-*-ext.xmi or ibm-*-bnd.xmi where * is the type of extension or binding file such as app, application, ejb-jar, or web. The following conditions apply:

• For apps and modules that use a Java EE version prior to version 5, the file extension must be .xmi.

• For apps and modules that use Java EE 5 or later, the file extension must be .xml. If .xmi files are included with the application or module, the product ignores the .xmi files.

However, a Java EE 5 or later module can exist within an application that includes pre-Java EE 5 files and uses the .xmi file name extension.

The ibm-webservices-ext.xmi, ibm-webservices-bnd.xmi, ibm-webservicesclient-bnd.xmi, ibm-webservicesclient-ext.xmi, and ibm-portlet-ext.xmi files continue to use the .xmi file extensions. sptcfg

Follow these steps if migration issues apply to the web application:

1. IBM internal servlets are used to enable special behavior such as file serving and serving servlets by class name. If a migrated application references internal servlets, the best practice is to enable or disable the functionality through the IBM WebSphere extensions XMI file, ibm-web-ext.xmi, located in each web module WEB-INF directory or using an assembly tool.

2. If using these configuration options are not viable, then verify the package names for the following internal servlets match what is used in your version 7 web deployment descriptor.

   Feature	Configuration Option	Servlet Class
   Directory browsing	directoryBrowsingEnabled="true"	com.ibm.ws.webcontainer.servlet.DirectoryBrowsingServlet
   Auto mapping of servlet paths	serveServletsByClassnameEnabled="true:	com.ibm.ws.webcontainer.servlet.SimpleFileServlet
   File serving	fileServingEnabled="true"	com.ibm.ws.webcontainer.servlet.FilterProxyServlet

3. Add the web container custom property, com.ibm.ws.webcontainer.contenttypecompatibility, with a value of V4, V5, V6, V7, and so on. The value is determined by the version the application is dependant on. Refer the Modifying the default web container configuration topics for details on how to modify this custom property. Because this property is a global setting, you must consider the effect on other applications.

Subtopics

• JSP migration best practices and considerations
  The standard JSP tags from JSP 1.1 such as jsp:include, jsp:useBean, and <%@ page %>, migrate successfully to JSP 2.0. However, there are several areas that must be considered when migrating JSP. This topic discusses the areas that you must consider when migrating JSP.

Related concepts:

Development and assembly tools

Related

Hot deployment and dynamic reloading
Migrating to Java SE 6
Modify the default web container configuration

Reference:

Web applications: Resources for learning
Configure JVM sendRedirect calls to use context root

Related information:

Rational Application Developer documentation

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