Spring 5 - HTTP Status 500 – Internal Server Error-CodePudding

I'm doing Website from tutorial and I'm using Spring. Sadly code from video is not working in my IDE.

There is pom.xml.

<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>
  <groupId>org.example</groupId>
  <artifactId>Travel</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>
  <name>Travel</name>
  <build>
    <plugins>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.8.1</version>
        <configuration>
          <release>17</release>
        </configuration>
      </plugin>
      <plugin>
        <artifactId>maven-war-plugin</artifactId>
        <version>3.2.3</version>
      </plugin>
    </plugins>
  </build>
  
  
  <dependencies>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>6.0.3</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>4.0.1</version>
    </dependency>
<dependency>
  <groupId>org.thymeleaf</groupId>
  <artifactId>thymeleaf</artifactId>
  <version>3.0.11.RELEASE</version>
</dependency>
    <dependency>
        <groupId>org.thymeleaf</groupId>
        <artifactId>thymeleaf-spring5</artifactId>
        <version>3.1.1.RELEASE</version>
    </dependency>
  </dependencies>

  
  
</project>

And WebConfing.

package main.config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.thymeleaf.spring5.SpringTemplateEngine;
import org.thymeleaf.spring5.view.ThymeleafViewResolver;
import org.thymeleaf.templateresolver.ServletContextTemplateResolver;

@Configuration
@EnableWebMvc
@ComponentScan("main")
public class WebConfig implements WebMvcConfigurer {

    @Autowired
    private WebApplicationContext context;
    
    @Bean
    public ServletContextTemplateResolver templateResolver() {
        ServletContextTemplateResolver resolver = new ServletContextTemplateResolver(context.getServletContext());
        resolver.setPrefix("/WEB-INF/view/");
        resolver.setSuffix(".html");
        return resolver;
    }
    
    @Bean
    public SpringTemplateEngine templateEngine() {
        SpringTemplateEngine templateEngine = new SpringTemplateEngine();
        templateEngine.setTemplateResolver(templateResolver());
        return templateEngine;
    }
    
    @Bean
    public ThymeleafViewResolver viewResolver() {
        ThymeleafViewResolver viewResolver = new ThymeleafViewResolver();
        viewResolver.setTemplateEngine(templateEngine());
        return viewResolver;
    }
    
    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }

}

When I try to put it in localhost i can see error 500 in browser and then this is from IDE:

sty 07, 2023 7:36:20 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Allocate exception for servlet [dispatcher]
java.lang.Error: Unresolved compilation problems: 
ServletContextTemplateResolver cannot be resolved to a type
ServletContextTemplateResolver cannot be resolved to a type
ServletContextTemplateResolver cannot be resolved to a type
The method getServletContext() from the type WebApplicationContext refers to the missing type ServletContext

at main.config.WebConfig.templateResolver(WebConfig.java:31)
at main.config.WebConfig$$SpringCGLIB$$0.CGLIB$templateResolver$1(<generated>)
at main.config.WebConfig$$SpringCGLIB$$2.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:258)
at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:331)
at main.config.WebConfig$$SpringCGLIB$$0.templateResolver(<generated>)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:568)
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:139)
at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:653)
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:491)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1324)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1161)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:561)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:521)
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:326)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:324)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:961)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:915)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:584)
at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:706)
at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:583)
at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:537)
at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:169)
at jakarta.servlet.GenericServlet.init(GenericServlet.java:158)
at jakarta.servlet.http.HttpServlet.init(HttpServlet.java:140)
at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:995)
at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:696)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:128)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:119)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:400)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:861)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1739)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52)
at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.base/java.lang.Thread.run(Thread.java:833)

So for sure this lines are wrong:

    @Bean
    public ServletContextTemplateResolver templateResolver() {
        ServletContextTemplateResolver resolver = new ServletContextTemplateResolver(context.getServletContext());
        resolver.setPrefix("/WEB-INF/view/");
        resolver.setSuffix(".html");
        return resolver;
    }

I tried to change it in this way:

    @Bean
    public ServletContextTemplateResolver templateResolver() {
        ServletContextTemplateResolver resolver = new ServletContextTemplateResolver((ServletContext) context.getServletContext());
        resolver.setPrefix("/WEB-INF/view/");
        resolver.setSuffix(".html");
        return resolver;
    }

Still same, 500 error.

CodePudding user response：

As you can see in the changelogs, Spring migrated to Jakarta EE in the 6.0 release.

In your pom.xml, you are using version 6.0.3 of spring-webmvc (which requires Jakarta EE) but also javax.servlet-api which is part of Java EE.

You basically have two options:

Migrate to Jakarta EE

Replace

    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>4.0.1</version>
    </dependency>

with

<dependency>
    <groupId>jakarta.servlet</groupId>
    <artifactId>jakarta.servlet-api</artifactId>
    <version>6.0.0</version>
    <scope>provided</scope>
</dependency>

This will then use version 6.0.0 of the Jakarta Servlet API instead of version 4.0.1 of the Java EE servlet API.

Alternatively, you can use an older version like 5.0.0.

Similarly, you would need to upgrade thymeleaf to 3.1.x as this version supports Spring 6 and Jakarta EE. For doing so, replace

<dependency>
  <groupId>org.thymeleaf</groupId>
  <artifactId>thymeleaf</artifactId>
  <version>3.0.11.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.thymeleaf</groupId>
    <artifactId>thymeleaf-spring5</artifactId>
    <version>3.1.1.RELEASE</version>
</dependency>

with

<dependency>
  <groupId>org.thymeleaf</groupId>
  <artifactId>thymeleaf</artifactId>
  <version>3.1.1.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.thymeleaf</groupId>
    <artifactId>thymeleaf-spring6</artifactId>
    <version>3.1.1.RELEASE</version>
</dependency>

so that Thymeleaf is compatible with your Spring version as well.

Aside from updating dependencies, it is also important to replace the use of ServletContextTemplateResolver with something else as these were changed in Spring 3.1.

Since it is a Spring application, you might be able to use SpringResourceTemplateResolver as described in this Tutorial for Thymeleaf 3.1:

@Bean
public SpringResourceTemplateResolver templateResolver(){
    // SpringResourceTemplateResolver automatically integrates with Spring's own
    // resource resolution infrastructure, which is highly recommended.
    SpringResourceTemplateResolver templateResolver = new SpringResourceTemplateResolver();
    templateResolver.setApplicationContext(this.applicationContext);
    templateResolver.setPrefix("/WEB-INF/templates/");
    templateResolver.setSuffix(".html");
    // HTML is the default value, added here for the sake of clarity.
    templateResolver.setTemplateMode(TemplateMode.HTML);
    // Template cache is true by default. Set to false if you want
    // templates to be automatically updated when modified.
    templateResolver.setCacheable(true);
    return templateResolver;
}

Alternatively, you might be able to use WebApplicationTemplateResolver which can work with both Java EE (using JavaxServletWebApplication) and Jakarta EE (using JakartaServletWebApplication):


    @Bean
    public WebApplicationTemplateResolver templateResolver() {
        WebApplicationTemplateResolver resolver = new WebApplicationTemplateResolver(JakartaServletWebApplication.buildApplication(context.getServletContext()));
        resolver.setPrefix("/WEB-INF/view/");
        resolver.setSuffix(".html");
        return resolver;
    }

Downgrade Spring

Another possibility is to use a version of Spring Webmvc before 6.x. For doing that, replace

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>6.0.3</version>
    </dependency>

with

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>5.3.24</version>
    </dependency>

However, when using 5.x versions of Spring, you would miss the other features of Spring 6.x (including possible future features).