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Simple Spring Web App isn't working in Tomcat

Time：01-15

I'm currently learning Spring MVC and making a simple Hello World web application with it. However, I have no idea why its not working (The WebApplicationInitializer doesn't get invoked).

Here's the 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>com.example</groupId>
  <artifactId>springmvctest</artifactId>
  <version>1.0</version>
  <packaging>war</packaging>

  <name>springmvctest Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>18</maven.compiler.source>
    <maven.compiler.target>18</maven.compiler.target>
    <java.version>18</java.version>
    <lombok.version>1.18.24</lombok.version>
    <log4jdbc.log4j2.version>1.16</log4jdbc.log4j2.version>
    <rest.assured.version>2.3.3</rest.assured.version>

    <start-class>java.WebInit</start-class>

  </properties>

  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.6.4</version>
  </parent>


  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-aop</artifactId>
      <version>5.0.1.RELEASE</version>
      <scope>compile</scope>
  </dependency>

    <dependency>
        <groupId>org.aspectj</groupId>
        <artifactId>aspectjweaver</artifactId>
        <version>1.8.12</version>
        <scope>compile</scope>
    </dependency>


    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </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-jdbc</artifactId>
    </dependency>
    <dependency>
        <groupId>com.h2database</groupId>
        <artifactId>h2</artifactId>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>${lombok.version}</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>org.bgee.log4jdbc-log4j2</groupId>
        <artifactId>log4jdbc-log4j2-jdbc4.1</artifactId>
        <version>${log4jdbc.log4j2.version}</version>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>com.jayway.restassured</groupId>
        <artifactId>rest-assured</artifactId>
        <version>${rest.assured.version}</version>
        <scope>test</scope>
    </dependency>
  </dependencies>

  <build>
    <finalName>springmvctest</finalName>

    <sourceDirectory> src/main/ </sourceDirectory>

    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>


          <plugin>
              <groupId>org.springframework.boot</groupId>
              <artifactId>spring-boot-maven-plugin</artifactId>
              <dependencies>
                  <dependency>
                      <groupId>org.springframework</groupId>
                      <artifactId>springloaded</artifactId>
                      <version>${spring-loaded.version}</version>
                  </dependency>
              </dependencies>
          </plugin>
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
          <configuration>
            <source>18</source>
            <target>18</target>
          </configuration>   
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-war-plugin</artifactId>
          <version>3.2.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

Here's the WebApplicationInitializer implementation:


package java;

import javax.servlet.ServletContext;
import javax.servlet.ServletRegistration;

import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;

public class WebInit implements WebApplicationInitializer {
    
    @Override
    public void onStartup(ServletContext servletContext) {
        AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
        context.register(WebConfig.class);
        context.setServletContext(servletContext);

        System.out.println("hi");
        // Create and register the DispatcherServlet
        DispatcherServlet servlet = new DispatcherServlet(context);

        ServletRegistration.Dynamic registration = servletContext.addServlet("app", servlet);
        registration.setLoadOnStartup(1);
        registration.addMapping("/");
    }

}

Here's the WebConfig:


package java;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.JstlView;

@Configuration
@EnableWebMvc
@ComponentScan("java")
public class WebConfig {
    
    @Bean
    public ViewResolver viewResolver() {
        InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
        viewResolver.setViewClass(JstlView.class);
        viewResolver.setPrefix("/WEB-INF/views/");
        viewResolver.setSuffix(".jsp");
 
        return viewResolver;
    }
}

And finally here's the Controller implementation:


package java;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
@RequestMapping("/")
public class TestController {
    
    @RequestMapping(value =  "/test", method = RequestMethod.GET)
    public String testMethod (Model model) {
        model.addAttribute("greeting", "Hello World 2");
        return "welcome";
    }
}

I have used clean install and run the .war on the Tomcat server

I tried entering 'http://localhost:8080/springmvctest/test' but it gave me a 404 error on the web, and no error in the output.

There are also no mentions of Spring in the output whatsoever, so I assume that Tomcat doesn't detect Spring ?

I'm using Tomcat 10.0.27 and VSCode as the text editor.

CodePudding user response：

Spring 2 / Spring 5 will not work on Tomcat 10, because Tomcat 10 is working with jakarta packages that are not present in Spring 2 / Spring 5, they are using javax packages. Either downgrade to Tomcat 9 or upgrade to Spring 3 / Spring 6 if you want to use Tomcat 10.

CodePudding user response：

Using the Spring Boot framework will be written as follows

Spring Boot 3

Project Structure

├── pom.xml
└── src
    └── main
        ├── java
        │   └── com
        │       └── example
        │           └── springmvctest
        │               ├── DemoSpringbootJspApplication.java
        │               └── TestController.java
        ├── resources
        │   └── application.properties
        └── webapp
            ├── index.jsp
            └── WEB-INF
                └── views
                    └── welcome.jsp

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 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>3.0.1</version>
        <!--<version>2.7.6</version>-->
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>springmvctest</artifactId>
    <packaging>war</packaging>
    <version>1.0</version>
    <name>springmvctest</name>
    <description>springmvctest</description>
    <properties>
        <java.version>17</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
                <exclusions>
                          <exclusion>
                            <groupId>org.springframework.boot</groupId>
                            <artifactId>spring-boot-starter-tomcat</artifactId>
                          </exclusion>  
                </exclusions>                               
        </dependency>

        <dependency>
            <groupId>org.apache.tomcat.embed</groupId>
            <artifactId>tomcat-embed-jasper</artifactId>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
            <finalName>${project.artifactId}</finalName>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

DemoSpringbootJspApplication.java

package com.example.springmvctest;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;

@SpringBootApplication
public class DemoSpringbootJspApplication extends SpringBootServletInitializer {
    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return application.sources(DemoSpringbootJspApplication.class);
    }
    
    public static void main(String[] args) {
        SpringApplication.run(DemoSpringbootJspApplication.class, args);
    }

}

TestController.java

package com.example.springmvctest;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;

import java.util.Map;

@Controller
@RequestMapping("/")
public class TestController {
    
    @RequestMapping(value =  "/test", method = RequestMethod.GET)
    public String testMethod (Model model) {
        model.addAttribute("greeting", "Hello World 2");
        return "welcome";
    }
}

application.properties

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

welcome.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Welcome</title>
</head>
<%
// debug
System.out.println("webapp / WEB-INF / views / welcome.jsp ");
%>
<body>
   <h1 >Wecome!  ${greeting} </h1>
</body>
</html>

Package

mvn clean package

Deploy and start

  • Put traget/springmvctest.war to apache-tomcat-10.1.4/webapps/

  • Startup tomcat

Test

Run Command

curl http://localhost:8080/springmvctest/test

Result

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Welcome</title>
</head>

<body>
   <h1 >Wecome!  Hello World 2 </h1>
</body>
</html>

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