Spring应用部署Heroku失败：Build Failure错误排查求助

问题描述 #

Heroku是一款平台即服务（PaaS），支持开发者完全在云端构建、运行和管理应用。我的Spring应用在本地运行正常，但部署到Heroku时出现构建失败（Build Failure）错误，请求协助解决。

错误日志 #

[INFO] Changes detected - recompiling the module!
[INFO] Compiling 25 source files to /tmp/build_d30a8927/target/classes
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  8.201 s
[INFO] Finished at: 2022-10-14T18:42:07Z
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.10.1:compile (default-compile) on project MyApp: Fatal error compiling: invalid target release: 17 -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException
 !     ERROR: Failed to build app with Maven
       We're sorry this build is failing! If you can't find the issue in application code,
       please submit a ticket so we can help: https://help.heroku.com/
 !     Push rejected, failed to compile Java app.
 !     Push failed

项目POM配置 #

<?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>2.7.3</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.spring.demo</groupId>
    <artifactId>MyApp</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>MyApp</name>
    <description>Demo project for MyApp</description>
    <properties>
        <java.version>17</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web-services</artifactId>
        </dependency>
    
        <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-security</artifactId>

</dependency>

<dependency>
    <groupId>org.thymeleaf.extras</groupId>
    <artifactId>thymeleaf-extras-springsecurity5</artifactId>
</dependency>
    
        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>
    </dependencies>

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

</project>

解决方案 #

核心问题是Heroku默认使用的Java版本低于项目指定的Java 17，导致编译时抛出invalid target release: 17错误，以下是两种可行的解决方式：

方式一：通过system.properties指定Java版本 #

在项目根目录创建system.properties文件，添加以下内容：

java.runtime.version=17

将该文件提交至Git仓库后重新部署，Heroku会自动使用Java 17环境进行构建。

方式二：在pom.xml中明确配置Maven编译插件 #

在pom.xml的<build>节点下的<plugins>中添加maven-compiler-plugin的版本及Java版本配置：

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.10.1</version>
    <configuration>
        <source>17</source>
        <target>17</target>
    </configuration>
</plugin>

建议同时结合方式一的system.properties配置，确保Heroku的运行和构建环境都使用Java 17，避免版本不一致问题。

注：Spring Boot 2.7.3原生支持Java 17，无需调整Spring Boot版本。

内容的提问来源于stack exchange，提问作者harry