public class TemplateServlet extends AbstractHttpServlet
It delegates work to a groovy.text.TemplateEngine implementation
processing HTTP requests.
helloworld.html is a headless HTML-like template
<html>
<body>
<% 3.times { %>
Hello World!
<% } %>
<br>
</body>
</html>
Minimal web.xml example serving HTML-like templates
<web-app>
<servlet>
<servlet-name>template</servlet-name>
<servlet-class>groovy.servlet.TemplateServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>template</servlet-name>
<url-pattern>*.html</url-pattern>
</servlet-mapping>
</web-app>
By default, the TemplateServer uses the SimpleTemplateEngine
which interprets JSP-like templates. The init parameter template.engine
defines the fully qualified class name of the template to use:
template.engine = [empty] - equals groovy.text.SimpleTemplateEngine template.engine = groovy.text.SimpleTemplateEngine template.engine = groovy.text.GStringTemplateEngine template.engine = groovy.text.XmlTemplateEngine
This implementation provides a verbosity flag switching log statements. The servlet init parameter name is:
generated.by = true(default) | false
The following servlet init parameter name can be used to specify the encoding TemplateServlet will use to read the template groovy source files:
groovy.source.encoding
AbstractHttpServlet.setVariables(ServletBinding),
Serialized FormCONTENT_TYPE_TEXT_HTML, encoding, INC_PATH_INFO, INC_REQUEST_URI, INC_SERVLET_PATH, INIT_PARAM_RESOURCE_NAME_REGEX, INIT_PARAM_RESOURCE_NAME_REGEX_FLAGS, namePrefix, reflection, resourceNamePattern, resourceNameReplaceAll, resourceNameReplacement, servletContext, verbose| Constructor and Description |
|---|
TemplateServlet()
Create new TemplateServlet.
|
| Modifier and Type | Method and Description |
|---|---|
protected Template |
getTemplate(File file)
Gets the template created by the underlying engine parsing the request.
|
protected Template |
getTemplate(URL url)
Gets the template created by the underlying engine parsing the request.
|
void |
init(ServletConfig config)
Initializes the servlet from hints the container passes.
|
protected TemplateEngine |
initTemplateEngine(ServletConfig config)
Creates the template engine.
|
void |
service(HttpServletRequest request,
HttpServletResponse response)
Services the request with a response.
|
applyResourceNameMatcher, generateNamePrefixOnce, getResourceConnection, getScriptUri, getScriptUriAsFile, removeNamePrefix, setVariablesdoDelete, doGet, doHead, doOptions, doPost, doPut, doTrace, getLastModified, servicedestroy, getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, log, logprotected Template getTemplate(File file) throws ServletException
This method looks up a simple (weak) hash map for an existing template object that matches the source file. If the source file didn't change in length and its last modified stamp hasn't changed compared to a precompiled template object, this template is used. Otherwise, there is no or an invalid template object cache entry, a new one is created by the underlying template engine. This new instance is put to the cache for consecutive calls.
file - The file containing the template source.ServletException - If the request specified an invalid template source fileprotected Template getTemplate(URL url) throws ServletException
This method looks up a simple (weak) hash map for an existing template object that matches the source URL. If there is no cache entry, a new one is created by the underlying template engine. This new instance is put to the cache for consecutive calls.
url - The URL containing the template source..ServletException - If the request specified an invalid template source URLpublic void init(ServletConfig config) throws ServletException
Delegates to sub-init methods and parses the following parameters:
init in interface Servletinit in class AbstractHttpServletconfig - Passed by the servlet container.ServletException - if this method encountered difficultiesinitTemplateEngine(ServletConfig)protected TemplateEngine initTemplateEngine(ServletConfig config)
Called by init(ServletConfig) and returns just
new groovy.text.SimpleTemplateEngine() if the init parameter
template.engine is not set by the container configuration.
config - Current servlet configuration passed by the container.null on error.public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
First the request is parsed for the source file uri. If the specified file could not be found or can not be read an error message is sent as response.
service in class HttpServletrequest - The http request.response - The http response.IOException - if an input or output error occurs while the servlet is handling the HTTP requestServletException - if the HTTP request cannot be handled