This guide show you how to use GSP as view templates with Spring Boot.
- Spring Boot 3.3.7
- Grace Framework 2023.3.0-M1
Adding grace-plugin-gsp plugin to the build.gradle,
dependencies {
implementation 'org.graceframework:grace-boot'
implementation 'org.graceframework:grace-plugin-core'
implementation 'org.graceframework:grace-plugin-gsp'
}In the following example, GreetingController is a Spring Controller, handles GET requests for /greeting by returning the name of a View (in this case, greeting/index).
A View is responsible for rendering the HTML content. The implementation of the method body relies on a view technology (in this case, GSP) to perform server-side rendering of the HTML.
@Controller
class GreetingController {
@GetMapping("/greeting")
String index(@RequestParam(name="name", required=false, defaultValue="World") String name, Model model) {
model.addAttribute("name", name)
return "greeting/index"
}
}Groovy Servers Pages (or GSP for short) is Grails' view technology. It is designed to be familiar for users of technologies such as ASP and JSP, but to be far more flexible and intuitive.
The following listing (from app/views/greeting/index.gsp) shows the index.gsp template:
<!DOCTYPE HTML>
<html>
<head>
<title>Spring Boot with GSP</title>
<meta name="layout" content="main"/>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
</head>
<body>
<h1><g:welcome/></h1>
<p>Hello, <b>${name}</b> from GSP!</p>
</body>
</html>All built-in GSP tags start with the prefix g:. Unlike JSP, you don’t specify any tag library imports. If a tag starts with g: it is automatically assumed to be a GSP tag. In this example (from app/taglib/grace/guides/GreetingTagLib.groovy) GreetingTagLib tag would look like:
class GreetingTagLib {
GrailsApplication grailsApplication
def welcome = { args, body ->
out << "Welcome to Grace " << grailsApplication.metadata.getGrailsVersion()
}
}A tag library is a simple Groovy class that ends with the convention TagLib and place it within the app/taglib directory.
./gradlew bootRungs-spring-boot-gsp ./gradlew bootRun
> Task :bootRun
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v3.3.7)
2025-01-19T07:23:01.848+08:00 INFO 92080 --- [ restartedMain] grace.guides.GraceBootApplication : Starting GraceBootApplication using Java 17.0.12 with PID 92080 (/Users/rain/Development/github/grace/grace-guides/gs-spring-boot-gsp/build/classes/groovy/main started by rain in /Users/rain/Development/github/grace/grace-guides/gs-spring-boot-gsp)
2025-01-19T07:23:01.849+08:00 INFO 92080 --- [ restartedMain] grace.guides.GraceBootApplication : No active profile set, falling back to 1 default profile: "default"
2025-01-19T07:23:01.868+08:00 INFO 92080 --- [ restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : Devtools property defaults active! Set 'spring.devtools.add-properties' to 'false' to disable
2025-01-19T07:23:01.868+08:00 INFO 92080 --- [ restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : For additional web related logging consider setting the 'logging.level.web' property to 'DEBUG'
2025-01-19T07:23:02.308+08:00 INFO 92080 --- [ restartedMain] g.plugins.DefaultGrailsPluginManager : Total 3 plugins loaded successfully, take in 43 ms
2025-01-19T07:23:02.564+08:00 INFO 92080 --- [ restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port 8080 (http)
2025-01-19T07:23:02.570+08:00 INFO 92080 --- [ restartedMain] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2025-01-19T07:23:02.570+08:00 INFO 92080 --- [ restartedMain] o.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/10.1.34]
2025-01-19T07:23:02.590+08:00 INFO 92080 --- [ restartedMain] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2025-01-19T07:23:02.591+08:00 INFO 92080 --- [ restartedMain] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 722 ms
2025-01-19T07:23:02.946+08:00 INFO 92080 --- [ restartedMain] o.s.b.d.a.OptionalLiveReloadServer : LiveReload server is running on port 35729
2025-01-19T07:23:02.952+08:00 INFO 92080 --- [ restartedMain] o.s.b.a.e.web.EndpointLinksResolver : Exposing 15 endpoints beneath base path '/actuator'
2025-01-19T07:23:03.066+08:00 INFO 92080 --- [ restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port 8080 (http) with context path '/'
2025-01-19T07:23:03.094+08:00 INFO 92080 --- [ restartedMain] grace.guides.GraceBootApplication : Started GraceBootApplication in 1.379 seconds (process running for 1.723)
2025-01-19T07:23:03.103+08:00 DEBUG 92080 --- [ restartedMain] PluginsInfoApplicationContextInitializer :
----------------------------------------------------------------------------------------------
Order Plugin Name Plugin Version Enabled
----------------------------------------------------------------------------------------------
1 Core 2023.3.0-M1 Y
2 Codecs 2023.3.0-M1 Y
3 GroovyPages 2023.3.0-M1 Y
----------------------------------------------------------------------------------------------then open your browser, http://localhost:8080/greeting
You will see it works!