JSP tricks to make templating easier

Question

At work I ve been tasked with turning a bunch of HTML files into a simple JSP project  It s really all static  no serverside logic to program  I should mention I m completely new to Java  JSP files seem to make it easy to work with common includes and variables  much like PHP  but I d like to know a simple way to get something like template inheritance  Django style  or at least be able to have a base jsp file containing the header and the footer  so I can insert content later   Ben Lings seems to offer some hope in his answer here  JSP template inheritance Can someone explain how to achieve this   Given that I don t have much time I think dynamic routing is a little much  so I m happy to just to have URLs map directly onto  jsp files  but I m open to suggestion   Thanks   edit  I don t want to use any external libraries  because it would increase the learning curve for myself and others who work on the project  and the company I work for has been contracted to do this   Another edit  I m not sure if JSP tags will be useful because my content doesn t really have any template variables  What I need is a way to be able to do this   base html    lt html gt  lt body gt    content body    lt  body gt  lt  html gt    somepage html   lt wrapper base html gt   lt h1 gt Welcome lt  h1 gt   lt  wrapper gt    with the output being    lt html gt  lt body gt   lt h1 gt Welcome lt  h1 gt   lt  body gt  lt  html gt    I think this would give me enough versatility to do everything I need  It could be achieved with includes but then I would need a top and a bottom include for each wrapper  which is kind of messy

User · Answer

Use tiles  It saved my life   But if you can t  there s the include tag  making it similar to php    The body tag might not actually do what you need it to  unless you have super simple content  The body tag is used to define the body of a specified element  Take a look at this example    lt jsp element name    content headerName         xmlns jsp  http   java sun com JSP Page  gt          lt jsp attribute name  lang  gt   content lang  lt  jsp attribute gt         lt jsp body gt   content body  lt  jsp body gt    lt  jsp element gt    You specify the element name  any attributes that element might have   lang  in this case   and then the text that goes in it--the body  So if    content headerName   h1  content lang   fr  and content body   Heading in French   Then the output would be   lt h1 lang  fr  gt Heading in French lt  h1 gt

User · Answer

I made quite easy  Django style JSP Template inheritance tag library  https   github com kwon37xi jsp-template-inheritance  I think it make easy to manage layouts without learning curve   example code    base jsp   layout   lt   page contentType  text html  charset UTF-8    gt   lt    taglib uri  http   kwonnam pe kr jsp template-inheritance  prefix  layout   gt   lt  DOCTYPE html gt   lt html lang  en  gt       lt head gt           lt title gt JSP Template Inheritance lt  title gt       lt  head gt    lt h1 gt Head lt  h1 gt   lt div gt       lt layout block name  header  gt          header      lt  layout block gt   lt  div gt    lt h1 gt Contents lt  h1 gt   lt div gt       lt p gt       lt layout block name  contents  gt           lt h2 gt Contents will be placed under this h2 lt  h2 gt       lt  layout block gt       lt  p gt   lt  div gt    lt div class  footer  gt       lt hr   gt       lt a href  https   github com kwon37xi jsp-template-inheritance  gt jsp template inheritance example lt  a gt   lt  div gt   lt  html gt    view jsp   contents   lt   page contentType  text html  charset UTF-8    gt   lt    taglib uri  http   kwonnam pe kr jsp template-inheritance  prefix  layout   gt   lt layout extends name  base jsp  gt       lt layout put name  header  type  REPLACE  gt           lt h2 gt This is an example about layout management with JSP Template Inheritance lt  h2 gt       lt  layout put gt       lt layout put name  contents  gt          Lorem ipsum dolor sit amet  consectetur adipiscing elit  Proin porta          augue ut ornare sagittis  diam libero facilisis augue  quis accumsan enim velit a mauris       lt  layout put gt   lt  layout extends gt

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Add dependecies for use  lt   tag description  quot User Page template quot  pageEncoding  quot UTF-8 quot   gt   lt dependencies gt       lt dependency gt           lt groupId gt javax servlet lt  groupId gt           lt artifactId gt servlet-api lt  artifactId gt           lt version gt 2 5 lt  version gt       lt  dependency gt       lt dependency gt           lt groupId gt javax servlet jsp lt  groupId gt           lt artifactId gt jsp-api lt  artifactId gt           lt version gt 2 2 lt  version gt           lt scope gt provided lt  scope gt       lt  dependency gt       lt dependency gt           lt groupId gt javax servlet jsp jstl lt  groupId gt           lt artifactId gt javax servlet jsp jstl-api lt  artifactId gt           lt version gt 1 2 1 lt  version gt       lt  dependency gt       lt dependency gt           lt groupId gt taglibs lt  groupId gt           lt artifactId gt standard lt  artifactId gt           lt version gt 1 1 2 lt  version gt       lt  dependency gt   lt  dependencies gt

User · Answer

I know this answer is coming years after the fact and there is already a great JSP answer by Will Hartung  but there is Facelets  they are even mentioned in the answers from the linked question in the original question   Facelets SO tag description     Facelets is an XML-based view technology for the JavaServer Faces framework  Designed specifically for JSF  Facelets is intended to be a simpler and more powerful alternative to JSP-based views  Initially a separate project  the technology was standardized as part of JSF 2 0 and Java-EE 6 and has deprecated JSP  Almost all JSF 2 0 targeted component libraries do not support JSP anymore  but only Facelets    Sadly the best plain tutorial description I found was on Wikipedia and not a tutorial site  In fact the section describing templates even does along the lines of what the original question was asking for   Due to the fact that Java-EE 6 has deprecated JSP I would recommend going with Facelets despite the fact that it looks like there might be more required for little to no gain over JSP

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As skaffman suggested  JSP 2 0 Tag Files are the bee s knees   Let s take your simple example   Put the following in WEB-INF tags wrapper tag   lt   tag description  Simple Wrapper Tag  pageEncoding  UTF-8   gt   lt html gt  lt body gt     lt jsp doBody  gt   lt  body gt  lt  html gt    Now in your example jsp page    lt   page contentType  text html  pageEncoding  UTF-8   gt   lt   taglib prefix  t  tagdir   WEB-INF tags    gt    lt t wrapper gt       lt h1 gt Welcome lt  h1 gt   lt  t wrapper gt    That does exactly what you think it does     So  lets expand upon that to something a bit more general  WEB-INF tags genericpage tag   lt   tag description  Overall Page template  pageEncoding  UTF-8   gt   lt   attribute name  header  fragment  true    gt   lt   attribute name  footer  fragment  true    gt   lt html gt     lt body gt       lt div id  pageheader  gt         lt jsp invoke fragment  header   gt       lt  div gt       lt div id  body  gt         lt jsp doBody  gt       lt  div gt       lt div id  pagefooter  gt         lt jsp invoke fragment  footer   gt       lt  div gt     lt  body gt   lt  html gt    To use this    lt   page contentType  text html  pageEncoding  UTF-8   gt   lt   taglib prefix  t  tagdir   WEB-INF tags    gt    lt t genericpage gt       lt jsp attribute name  header  gt         lt h1 gt Welcome lt  h1 gt       lt  jsp attribute gt       lt jsp attribute name  footer  gt         lt p id  copyright  gt Copyright 1927  Future Bits When There Be Bits Inc  lt  p gt       lt  jsp attribute gt       lt jsp body gt           lt p gt Hi I m the heart of the message lt  p gt       lt  jsp body gt   lt  t genericpage gt    What does that buy you  A lot really  but it gets even better       WEB-INF tags userpage tag   lt   tag description  User Page template  pageEncoding  UTF-8   gt   lt   taglib prefix  t  tagdir   WEB-INF tags    gt   lt   attribute name  userName  required  true   gt    lt t genericpage gt       lt jsp attribute name  header  gt         lt h1 gt Welcome   userName  lt  h1 gt       lt  jsp attribute gt       lt jsp attribute name  footer  gt         lt p id  copyright  gt Copyright 1927  Future Bits When There Be Bits Inc  lt  p gt       lt  jsp attribute gt       lt jsp body gt           lt jsp doBody  gt       lt  jsp body gt   lt  t genericpage gt    To use this   assume we have a user variable in the request    lt   page contentType  text html  pageEncoding  UTF-8   gt   lt   taglib prefix  t  tagdir   WEB-INF tags    gt    lt t userpage userName    user fullName   gt     lt p gt      First Name    user firstName   lt br  gt      Last Name    user lastName   lt br  gt      Phone    user phone  lt br  gt     lt  p gt   lt  t userpage gt      But it turns you like to use that user detail block in other places  So  we ll refactor it  WEB-INF tags userdetail tag   lt   tag description  User Page template  pageEncoding  UTF-8   gt   lt   tag import  com example User    gt   lt   attribute name  user  required  true  type  com example User   gt   First Name    user firstName   lt br  gt  Last Name    user lastName   lt br  gt  Phone    user phone  lt br  gt    Now the previous example becomes    lt   page contentType  text html  pageEncoding  UTF-8   gt   lt   taglib prefix  t  tagdir   WEB-INF tags    gt    lt t userpage userName    user fullName   gt     lt p gt       lt t userdetail user    user    gt     lt  p gt   lt  t userpage gt      The beauty of JSP Tag files is that it lets you basically tag generic markup and then refactor it to your heart s content   JSP Tag Files have pretty much usurped things like Tiles etc   at least for me  I find them much easier to use as the only structure is what you give it  nothing preconceived  Plus you can use JSP tag files for other things  like the user detail fragment above    Here s an example that is similar to DisplayTag that I ve done  but this is all done with Tag Files  and the Stripes framework  that s the s  tags     This results in a table of rows  alternating colors  page navigation  etc    lt t table items    actionBean customerList   var  obj  css class  display  gt     lt t col css class  checkboxcol  gt       lt s checkbox name  customerIds  value    obj customerId                   onclick  handleCheckboxRangeSelection this  event     gt     lt  t col gt     lt t col name  customerId  title  ID   gt     lt t col name  firstName  title  First Name   gt     lt t col name  lastName  title  Last Name   gt     lt t col gt       lt s link href   Customer action  event  preEdit  gt        Edit        lt s param name  customer customerId  value    obj customerId    gt         lt s param name  page  value    actionBean page    gt       lt  s link gt     lt  t col gt   lt  t table gt    Of course the tags work with the JSTL tags  like c if  etc    The only thing you can t do within the body of a tag file tag is add Java scriptlet code  but this isn t as much of a limitation as you might think  If I need scriptlet stuff  I just put the logic in to a tag and drop the tag in  Easy   So  tag files can be pretty much whatever you want them to be  At the most basic level  it s simple cut and paste refactoring  Grab a chunk of layout  cut it out  do some simple parameterization  and replace it with a tag invocation   At a higher level  you can do sophisticated things like this table tag I have here

User · Answer

This can also be achieved with jsp include  Chad Darby explains well here in this video https   www youtube com watch v EWbYj0qoNHo

User · Answer

Based on the same basic idea as in  Will Hartung s answer  here is my magic one-tag extensible template engine  It even includes documentation and an example  -   WEB-INF tags block tag    lt  --     The block tag implements a basic but useful extensible template system       A base template consists of a block tag without a  template  attribute      The template body is specified in a standard jsp body tag  which can     contain EL  JSTL tags  nested block tags and other custom tags  but     cannot contain scriptlets  scriptlets are allowed in the template file      but only outside of the body and attribute tags   Templates can be     full-page templates  or smaller blocks of markup included within a page       The template is customizable by referencing named attributes within     the body  via EL   Attribute values can then be set either as attributes     of the block tag element itself  convenient for short values   or by     using nested jsp attribute elements  better for entire blocks of markup        Rendering a template block or extending it in a child template is then     just a matter of invoking the block tag with the  template  attribute set     to the desired template name  and overriding template-specific attributes     as necessary to customize it       Attribute values set when rendering a tag override those set in the template     definition  which override those set in its parent template definition  etc      The attributes that are set in the base template are thus effectively used     as defaults  Attributes that are not set anywhere are treated as empty       Internally  attributes are passed from child to parent via request-scope     attributes  which are removed when rendering is complete       Here s a contrived example              WEB-INF tags block tag  the template engine tag        lt the file you re looking at right now gt              WEB-INF templates base jsp  base template        lt    page trimDirectiveWhitespaces  true    gt       lt    taglib prefix  t  tagdir   WEB-INF tags    gt       lt t block gt           lt jsp attribute name  title  gt Template Page lt  jsp attribute gt           lt jsp attribute name  style  gt               footer   font-size  smaller  color   aaa                 content   margin  2em  color   009                  moreStyle           lt  jsp attribute gt           lt jsp attribute name  footer  gt               lt div class  footer  gt                  Powered by the block tag              lt  div gt           lt  jsp attribute gt           lt jsp body gt               lt html gt                   lt head gt                       lt title gt   title  lt  title gt                       lt style gt                            style                       lt  style gt                   lt  head gt                   lt body gt                       lt h1 gt   title  lt  h1 gt                       lt div class  content  gt                            content                       lt  div gt                        footer                   lt  body gt               lt  html gt           lt  jsp body gt       lt  t block gt              WEB-INF templates history jsp  child template        lt    page trimDirectiveWhitespaces  true    gt       lt    taglib prefix  t  tagdir   WEB-INF tags    gt       lt t block template  base  title  History Lesson  gt           lt jsp attribute name  content  trim  false  gt               lt p gt   shooter  shot first  lt  p gt           lt  jsp attribute gt       lt  t block gt              history-1977 jsp  a page using child template        lt    page trimDirectiveWhitespaces  true    gt       lt    taglib prefix  t  tagdir   WEB-INF tags    gt       lt t block template  history  shooter  Han    gt              history-1997 jsp  a page using child template        lt    page trimDirectiveWhitespaces  true    gt       lt    taglib prefix  t  tagdir   WEB-INF tags    gt       lt t block template  history  title  Revised History Lesson  gt           lt jsp attribute name  moreStyle  gt  revised   font-style  italic    lt  jsp attribute gt           lt jsp attribute name  shooter  gt  lt span class  revised  gt Greedo lt  span gt  lt  jsp attribute gt       lt  t block gt   --  gt    lt    tag trimDirectiveWhitespaces  true    gt   lt    tag import  java util HashSet  java util Map  java util Map Entry    gt   lt    tag dynamic-attributes  dynattributes    gt   lt    attribute name  template    gt   lt          get template name  adding default  jsp extension if it does not contain        any      and  WEB-INF templates  prefix if it does not start with a          String template    String jspContext getAttribute  template        if  template    null            if   template contains                   template      jsp           if   template startsWith                   template     WEB-INF templates     template               copy dynamic attributes into request scope so they can be accessed from included template page         child is processed before parent template  so only set previously undefined attributes      Map lt String  String gt  dynattributes    Map lt String  String gt  jspContext getAttribute  dynattributes        HashSet lt String gt  addedAttributes   new HashSet lt String gt         for  Map Entry lt String  String gt  e   dynattributes entrySet              if  jspContext getAttribute e getKey    PageContext REQUEST SCOPE     null                jspContext setAttribute e getKey    e getValue    PageContext REQUEST SCOPE               addedAttributes add e getKey                       gt    lt   if  template    null       this is the base template itself  so render it   gt       lt jsp doBody  gt   lt     else      this is a page using the template  so include the template instead   gt       lt jsp include page   lt    template   gt     gt   lt       gt    lt          clean up the added attributes to prevent side effect outside the current tag     for  String key   addedAttributes            jspContext removeAttribute key  PageContext REQUEST SCOPE           gt

[java] JSP tricks to make templating easier?

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