如何使用Eclipse IDE在Google App Engine（GAE）上部署Spring Boot应用程序？

Question

I've created a spring boot application, and I want to deploy it on Google App Engine(GAE). With reference to that following are the things I've done.

1. Created spring boot app
2. Added appengine-web.xml and web.xml under webapp/WEB-INF
3. Configured Project ID and Version details under Google app engine settings
4. install maven depencencies using Maven install

Now, when I try to run my application using spring boot or google web application, it gives tomcat connection error.

Following are the related files, appengine-web.xml

<?xml version="1.0" encoding="utf-8"?>
<appengine-web-app xmlns="http://appengine.google.com/ns/1.0">
    <application>appname</application>
    <version>1</version>
    <threadsafe>true</threadsafe>
</appengine-web-app>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>org.example.Application</param-value>
    </context-param>

    <listener>
        <listener-class>org.springframework.boot.legacy.context.web.SpringBootContextLoaderListener</listener-class>
    </listener>

    <filter>
        <filter-name>metricFilter</filter-name>
        <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
    </filter>

    <filter-mapping>
        <filter-name>metricFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <servlet>
        <servlet-name>appServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextAttribute</param-name>
            <param-value>org.springframework.web.context.WebApplicationContext.ROOT</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>appServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

</web-app>

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 http://maven.apache.org/maven-v4_0_0.xsd">

    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>spring-boot-fundamentals</artifactId>
    <version>1.0-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.2.1.RELEASE</version>
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.version>1.7</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-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-legacy</artifactId>
            <version>1.0.2.RELEASE</version>
        </dependency>
    </dependencies>

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

Answer 1

Before Spring Boot, I used to deploy an application to GAE using Google plugin. But for Spring Boot application, it's completely different. Just add appengine-web.xml and web.xml files under webapp/WEB-INF folder and use "mvn appengine:update" to deploy the application.

Answer 2

You are missing a number of the steps required to convert a Spring Boot application for App Engine Standard . In your particular case you need to:

• Use WAR packaging instead of JAR packaging
• Remove the Tomcat Starter and add the javax.servlet-api
• Add the com.google.cloud.tools App Engine plugin to pom.xml
• Set the runtime to java8 in appengine-web.xml
• Exclude the JUL to SLF4J Bridge to ensure full logging

Or you could simply base yourself on the configuration in this sample Spring Boot application .

I would go into more details but then I'd simply be rewriting the source material, which I encourage you to read.