last modified October 18, 2023
Spring forward tutorial shows how to forward a request in a Spring web application.
Spring is a popular Java application framework for creating enterprise applications.
The special forward: prefix in a view name performs a forward to
different URL. Forwarding a URL transfers the request internally within the
same server without involving the client browser. Forwards are performed
less often than redirects.
A request can be basically processed in three ways: a) resolved by Spring in a controller action, b) forwarded to a different controller action, c) redirected to client to fetch another URL.
Forward:
Redirect:
The following application uses forwards to a different URL after a form submission.
It performs a forward with the forward: prefix.
pom.xml src ├───main │ ├───java │ │ └───com │ │ └───zetcode │ │ ├───config │ │ │ MyWebInitializer.java │ │ │ WebConfig.java │ │ └───controller │ │ MyController.java │ └───resources │ │ logback.xml │ │ │ └───templates │ show.ftl └───test └───java
This is the project structure.
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.zetcode</groupId> <artifactId>springforwardex</artifactId> <version>1.0-SNAPSHOT</version> <packaging>war</packaging> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <maven.compiler.source>17</maven.compiler.source> <maven.compiler.target>17</maven.compiler.target> <spring-version>5.3.23</spring-version> </properties> <dependencies> <dependency> <groupId>ch.qos.logback</groupId> <artifactId>logback-classic</artifactId> <version>1.4.0</version> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>4.0.1</version> <scope>provided</scope> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>5.3.23</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context-support</artifactId> <version>5.3.23</version> </dependency> <dependency> <groupId>org.freemarker</groupId> <artifactId>freemarker</artifactId> <version>2.3.28</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-war-plugin</artifactId> <version>3.3.2</version> </plugin> <plugin> <groupId>org.eclipse.jetty</groupId> <artifactId>jetty-maven-plugin</artifactId> <version>9.4.49.v20220914</version> </plugin> </plugins> </build> </project>
In the pom.xml we have the necessary dependencies.
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<logger name="org.springframework" level="ERROR"/>
<logger name="com.zetcode" level="INFO"/>
<appender name="consoleAppender" class="ch.qos.logback.core.ConsoleAppender">
<encoder>
<Pattern>%d{HH:mm:ss.SSS} %blue(%-5level) %magenta(%logger{36}) - %msg %n
</Pattern>
</encoder>
</appender>
<root>
<level value="INFO" />
<appender-ref ref="consoleAppender" />
</root>
</configuration>
The logback.xml is a configuration file for the Logback logging library.
package com.zetcode.config;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
@Configuration
public class MyWebInitializer extends
AbstractAnnotationConfigDispatcherServletInitializer {
@Override
protected Class<?>[] getRootConfigClasses() {
return null;
}
@Override
protected Class<?>[] getServletConfigClasses() {
return new Class[]{WebConfig.class};
}
@Override
protected String[] getServletMappings() {
return new String[]{"/"};
}
}
MyWebInitializer registers the Spring DispatcherServlet, which
is a front controller for a Spring web application.
@Override
protected Class<?>[] getServletConfigClasses() {
return new Class[]{WebConfig.class};
}
The getServletConfigClasses returns a web configuration class.
package com.zetcode.config;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.view.freemarker.FreeMarkerConfigurer;
import org.springframework.web.servlet.view.freemarker.FreeMarkerViewResolver;
@Configuration
@EnableWebMvc
@ComponentScan(basePackages = {"com.zetcode"})
public class WebConfig implements WebMvcConfigurer {
@Bean
public FreeMarkerViewResolver freemarkerViewResolver() {
var resolver = new FreeMarkerViewResolver();
resolver.setCache(true);
resolver.setSuffix(".ftl");
return resolver;
}
@Bean
public FreeMarkerConfigurer freemarkerConfig() {
var freeMarkerConfigurer = new FreeMarkerConfigurer();
freeMarkerConfigurer.setTemplateLoaderPath("classpath:/templates/");
return freeMarkerConfigurer;
}
}
WebConfig configures Freemarker. We set the template files location
to templates directory on the classpath. (The
resources is on the classpath.)
package com.zetcode.controller;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
@Controller
public class MyController {
private static final Logger logger = LoggerFactory.getLogger(MyController.class);
@GetMapping(value = "/sendname")
public String send(@RequestParam(defaultValue = "guest") String name, Model model) {
logger.info("sendname called");
model.addAttribute("name", name);
return "forward:/newpage";
}
@GetMapping(value = "/newpage")
public String newpage() {
logger.info("newpage called");
return "show";
}
}
MyController provides two GET mappings.
@GetMapping(value = "/sendname")
public String send(@RequestParam(defaultValue = "guest") String name, Model model) {
logger.info("send name called");
model.addAttribute("name", name);
return "forward:/newpage";
}
A request sent to /sendname is processed by send action.
A request parameter is read and added to the model. In the end, it is forwarded
to a new controller action.
@GetMapping(value = "/newpage")
public String newpage() {
logger.info("newpage called");
return "show";
}
The newpage action resolves the request to a show
view.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Show</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
</head>
<body>
<p>
User name: ${name}
</p>
</body>
</html>
The show.ftl display the user name.
$ mvn jetty:run
We run the server and locate to localhost:8080/sendname?name=Peter.
09:52:11.636 INFO com.zetcode.controller.MyController - sendname called 09:52:11.653 INFO com.zetcode.controller.MyController - newpage called
The server log contains these lines.
In this article we have performed a forward in a Spring controller.
My name is Jan Bodnar, and I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and 8 e-books. I possess more than ten years of experience in teaching programming.
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