public class TemplateServlet extends AbstractHttpServlet
A generic servlet for serving (mostly HTML) templates.
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
| Fields inherited from class | Fields |
|---|---|
class AbstractHttpServlet |
CONTENT_TYPE_TEXT_HTML, INC_PATH_INFO, INC_REQUEST_URI, INC_SERVLET_PATH, INIT_PARAM_RESOURCE_NAME_REGEX, INIT_PARAM_RESOURCE_NAME_REGEX_FLAGS, encoding, namePrefix, reflection, resourceNamePattern, resourceNameReplaceAll, resourceNameReplacement, servletContext, verbose |
| Constructor and description |
|---|
TemplateServlet
()Create new TemplateServlet. |
| Type Params | Return Type | Name 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. |
|
public void |
init(ServletConfig config)Initializes the servlet from hints the container passes. |
|
protected TemplateEngine |
initTemplateEngine(ServletConfig config)Creates the template engine. |
|
public void |
service(HttpServletRequest request, HttpServletResponse response)Services the request with a response. |
| Methods inherited from class | Name |
|---|---|
class AbstractHttpServlet |
applyResourceNameMatcher, generateNamePrefixOnce, getResourceConnection, getScriptUri, getScriptUriAsFile, init, removeNamePrefix, setVariables |
Gets the template created by the underlying engine parsing the request.
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.Gets the template created by the underlying engine parsing the request.
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..Initializes the servlet from hints the container passes.
Delegates to sub-init methods and parses the following parameters:
config - Passed by the servlet container.Creates the template engine.
Called by TemplateServlet.init 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.Services the request with a response.
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.
request - The http request.response - The http response.Copyright © 2003-2021 The Apache Software Foundation. All rights reserved.