How to use JSP in Spring Boot-CodePudding

Configured Spring Boot according to a guide, still it cannot find my jsp views. So after launching I get this message "This application has no explicit mapping for /error, so you are seeing this as a fallback."

Any suggestions?

pom:

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.7.5</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.lib.secondtry</groupId>
    <artifactId>MyLibrary</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>MyLibrary</name>
    <description>MyLibrary</description>
    <properties>
        <java.version>11</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.apache.tomcat.embed</groupId>
            <artifactId>tomcat-embed-jasper</artifactId>
            <version>9.0.44</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.tomcat.embed</groupId>
            <artifactId>tomcat-embed-jasper</artifactId>
            <version>9.0.44</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>

        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

Properties:

spring.mvc.view.prefix=/webapp/WEB-INF/jsp/
spring.mvc.view.suffix=.jsp

Controller:

@Controller
public class FirstController {
    @GetMapping("/")
    public String sayHello(){
        return "hello";
    }
}

Console:

2022-11-15 23:09:26.879  INFO 11896 --- [  restartedMain] c.l.s.mylibrary.MyLibraryApplication     : No active profile set, falling back to 1 default profile: "default"
2022-11-15 23:09:26.907  INFO 11896 --- [  restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : Devtools property defaults active! Set 'spring.devtools.add-properties' to 'false' to disable
2022-11-15 23:09:26.908  INFO 11896 --- [  restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : For additional web related logging consider setting the 'logging.level.web' property to 'DEBUG'
2022-11-15 23:09:27.369  INFO 11896 --- [  restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2022-11-15 23:09:27.374  INFO 11896 --- [  restartedMain] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2022-11-15 23:09:27.375  INFO 11896 --- [  restartedMain] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.68]
2022-11-15 23:09:27.495  INFO 11896 --- [  restartedMain] org.apache.jasper.servlet.TldScanner     : At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
2022-11-15 23:09:27.500  INFO 11896 --- [  restartedMain] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2022-11-15 23:09:27.501  INFO 11896 --- [  restartedMain] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 593 ms
2022-11-15 23:09:27.663  INFO 11896 --- [  restartedMain] o.s.b.d.a.OptionalLiveReloadServer       : LiveReload server is running on port 35729
2022-11-15 23:09:27.694  INFO 11896 --- [  restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2022-11-15 23:09:27.700  INFO 11896 --- [  restartedMain] c.l.s.mylibrary.MyLibraryApplication     : Started MyLibraryApplication in 1.008 seconds (JVM running for 1.342)
2022-11-15 23:09:43.705  INFO 11896 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2022-11-15 23:09:43.705  INFO 11896 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2022-11-15 23:09:43.706  INFO 11896 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 1 ms

In main I created webapp/WEB-INF/jsp/ and it didn't help.

CodePudding user response：

try in your .properties to change it into

spring.mvc.view.prefix=/WEB-INF/jsp/
spring.mvc.view.suffix=.jsp

if it still dont work i would like to see the error in console or the stack trace.

CodePudding user response：

Gotcha at "JSP Limitations";

When running a Spring Boot application that uses an embedded servlet container (and is packaged as an executable archive), there are some limitations in the JSP support.

With Jetty and Tomcat, it should work if you use war packaging. An executable war will work when launched with java -jar, and will also be deployable to any standard container. JSPs are not supported when using an executable jar.

Undertow does not support JSPs.

Creating a custom error.jsp page does not override the default view for error handling. Custom error pages should be used instead.

In maven (if omit) default packaging is jar, so please add:

to pom.xml:

<project>
   ...
   <packaging>war</packaging>
   ...

to build.gradle:
```
plugins {
   ...
   id 'war'
   ...
}
```
or at https://start.spring.io/#!packaging=war (which also sets spring-boot-starter-tomcat to prvoided scope (i.e. excludes it from packaging/prepares for external deployment))

(With all of its consequences.)

Please Also Note "Tip":

If possible, JSPs should be avoided. There are several known limitations when using them with embedded servlet containers.