How view-file mapping works on Spring - spring

Question

I don't understand how Spring maps view to files (e.g. "Homepage" view to "Home.jsp"). On Websphere you would find it in an XML file. On Spring I see that you map end-points to view on controllers in a Java class, but I cannot actually find how I can choose to map a specific view to a specific file.
Thank you
EDIT 1:
It seems like my first problem is that JSP support is not enabled. This is my Pom.xml:
<?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>org.springframework</groupId>
<artifactId>gs-serving-web-content</artifactId>
<version>0.1.0</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.10.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<properties>
<java.version>1.8</java.version>
</properties>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
If I add:
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-jasper</artifactId>
<scope>provided</scope>
</dependency>
Then I get an error on my pom.xml:
The managed version is 8.5.27 The artifact is managed in org.springframework.boot:spring-boot-dependencies:1.5.10.RELEASE
The file reported is org.springframework.boot:spring-boot-dependencies:1.5.10.RELEASE.pom and the line report is:
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-jasper</artifactId>
<version>${tomcat.version}</version>
</dependency>
EDIT 2:
Please consider that, even if I set my spring.mvc.view.suffix: .html, I get error 500 when I try to access http://localhost:8080/greeting. Here it is my console error:
2018-03-11 21:24:40.923 ERROR 4892 --- [nio-8080-exec-5] org.thymeleaf.TemplateEngine : [THYMELEAF][http-nio-8080-exec-5] Exception processing template "greeting": Error resolving template "greeting", template might not exist or might not be accessible by any of the configured Template Resolvers
2018-03-11 21:24:40.924 ERROR 4892 --- [nio-8080-exec-5] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.thymeleaf.exceptions.TemplateInputException: Error resolving template "greeting", template might not exist or might not be accessible by any of the configured Template Resolvers] with root cause
org.thymeleaf.exceptions.TemplateInputException: Error resolving template "greeting", template might not exist or might not be accessible by any of the configured Template Resolvers

Answer 1

You need to provide two things to Spring's ViewResolver if you want it to find your view files:
prefix - path to the folder where all searching begins.
suffix - extension of your views.
You can do this via xml:
<bean id="viewResolver"
class="org.springframework.web.servlet.view.InternalResourceViewResolver" >
<property name="prefix">
<value>/WEB-INF/pages/</value>
</property>
<property name="suffix">
<value>.jsp</value>
</property>
</bean>
Via application.properties:
spring.mvc.view.prefix: /WEB-INF/pages/
spring.mvc.view.suffix: .jsp
Via Java Config:
#Bean
public ViewResolver getViewResolver(){
InternalResourceViewResolver resolver = new InternalResourceViewResolver();
resolver.setPrefix("/WEB-INF/pages/");
resolver.setSuffix(".jsp");
return resolver;
}
So if you have file /WEB-INF/jsp/home.jsp Spring can find the file only having hello string.
If you have two hello.jsp in different folders it won't be a problem because you need to explicitly tell in what folder your view is reside(for example, you will specify return "/foo/hello" or return "/bar/hello")