在 Heroku 上部署我的 Spring Boot 项目时出错（目标版本无效）

Question

// pom.xml 文件

4.0.0 org.springframework.boot spring-boot-starter-parent 2.3.3.RELEASE com.SpringBootJavaProject LearningProject 0.0.1-SNAPSHOT LearningProject Spring Boot 演示项目

<properties>
    <java.version>14</java.version>
</properties>

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

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <scope>runtime</scope>
        <optional>true</optional>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
        <exclusions>
            <exclusion>
                <groupId>org.junit.vintage</groupId>
                <artifactId>junit-vintage-engine</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
</dependencies>

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

        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-surefire-plugin</artifactId>
            </plugin>

        <plugin>
            <groupId>com.heroku.sdk</groupId>
            <artifactId>heroku-maven-plugin</artifactId>
            <version>3.0.3</version>
        </plugin>
    </plugins>


</build>

// 错误描述 [ERROR] 无法执行目标 org.apache.maven.plugins:maven-compiler-plugin:3.8.1:compile (default-compile) on project LearningProject: Fatal error compiling: invalid target release: 14 -> [帮助1]

Answer 1

Heroku 默认使用 OpenJDK 8。

更改为使用 Java 8 或在 system.properties 文件（位于项目的根目录）中设置所需的 Java 版本，该文件应包含：

java.runtime.version=14