Unable to run localhost in Spring Boot application (Tomcat server)

问题

I've been learning Spring using the following tutorials: https://www.youtube.com/playlist?list=PLqq-6Pq4lTTbx8p2oCgcAQGQyqN8XeA1x

I have created a Maven project and tried to run the Spring Boot application while referring to these videos:

https://www.youtube.com/watch?v=E7_a-kB46LU&index=9&list=PLqq-6Pq4lTTbx8p2oCgcAQGQyqN8XeA1x

I tried to run my Spring application on Tomcat server but the localhost isn't working. (Port 8080)

My pom.xml looks like this:

<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>io.javabrains.springbootquickstart</groupId>
  <artifactId>course-api-new</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <name>Java Brains Course API</name>

  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.4.2.RELEASE</version>
  </parent>

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

  <properties>
        <java.version>1.8</java.version>
  </properties>

</project>

CourseApiApp.java :

package io.javabrains.springbootstarter;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class CourseApiApp {

    public static void main(String[] args) {
        SpringApplication.run(CourseApiApp.class, args);

    }

}

According to the video localhost should display Whitelist error on running the application, but it doesn't run at all.

Any help would be appreciated, thanks!

回答1:

I would suggest that you start your project from beginning. To create a valid spring-boot project you have a very good web based generator for spring-boot starter applications.

• https://start.spring.io/

For a web application with an embedded tomcat you should use web project.

Using STS you can create the same by choosing new -> spring starter project.

A wizard will appear and you can choose your project informations:

And then in the second step you dependencies:

After generating your project your pom.xml should look like that:

<?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>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

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

Your application should start normally and tomcat listens on localhost:8080.

EDIT The starter just have a new design:

回答2:

It could be possible that STS by default uses Tomcat version 7 and if you happen to use version 8, then would need to specify the same in pom.xml

<properties>
    <tomcat.version>8.0.47</tomcat.version>
</properties>

回答3:

You should try to run spring-boot as sudo

sudo mvn spring-boot:run

回答4:

I also faced the same issue. Try creating Spring Boot apprlication by choosing Spring Boot starter project in STS. Right click on STS->New->Spring Starter Project->Give name and click on Next->Choose Web and tick mark on Web and search for Dev Tools and tick mark Dev Tools and click on Finish

Now click on the project and Run as Spring Boot Application.

回答5:

In application.properties put server.port=8080

回答6:

I faced the similar issue. I too was following the JavaBrains SpringBoot example. This is what I did: I created a fresh spring boot project using STS tool and included the same code as provided by you and it worked!

回答7:

Missing web starter dependency.

No need to create new app .Just change this starter dependency to starter-web dependency:

---

starter

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

---

Starter web

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

回答8:

You need to tell springboot where do you have to scan your reference classes

@SpringBootApplication
@ComponentScan(basePackages= {"com.testbean.controller", "com.testbean.model", "com.testbean.service"}) 
public class DemoApplication {

来源：https://stackoverflow.com/questions/45030405/unable-to-run-localhost-in-spring-boot-application-tomcat-server