java - 使用 Maven 在 Eclipse 中运行项目时出错 "Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile"

Question

我正在使用 eclipse 和 maven 学习 google app engine 程序，但自 2 天以来我一直陷入这个错误。我在互联网上到处查找，但无法找到解决我的问题的方法。

这是控制台输出

[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building helloworld 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] >>> appengine-maven-plugin:1.9.4:devserver (default-cli) > package @ helloworld >>>
[INFO] 
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ helloworld ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory /Users/AdioJack/Developer/Scalable Apps (Udacity)/ud859-master/Lesson_2/000_Hello_Endpoints/src/main/resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ helloworld ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 3 source files to /Users/AdioJack/Developer/Scalable Apps (Udacity)/ud859-master/Lesson_2/000_Hello_Endpoints/target/helloworld-1.0-SNAPSHOT/WEB-INF/classes
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.462 s
[INFO] Finished at: 2014-09-10T12:34:38+05:30
[INFO] Final Memory: 6M/81M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile (default-compile) on project helloworld: Fatal error compiling: invalid target release: 1.7 -> [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

这是 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>
    <packaging>war</packaging>
    <version>1.0-SNAPSHOT</version>

    <groupId>com.google.training.helloworld</groupId>
    <artifactId>helloworld</artifactId>

    <properties>
        <appengine.app.version>1</appengine.app.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <prerequisites>
        <maven>3.1.0</maven>
    </prerequisites>

    <dependencies>
        <!-- Compile/runtime dependencies -->
        <dependency>
            <groupId>com.google.appengine</groupId>
            <artifactId>appengine-api-1.0-sdk</artifactId>
            <version>1.9.4</version>
        </dependency>
        <dependency>
            <groupId>com.google.appengine</groupId>
            <artifactId>appengine-endpoints</artifactId>
            <version>1.9.4</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>javax.inject</groupId>
            <artifactId>javax.inject</artifactId>
            <version>1</version>
        </dependency>

        <!-- Test Dependencies -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.google.appengine</groupId>
            <artifactId>appengine-testing</artifactId>
            <version>1.9.4</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.google.appengine</groupId>
            <artifactId>appengine-api-stubs</artifactId>
            <version>1.9.4</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <!-- for hot reload of the web application-->
        <outputDirectory>${project.build.directory}/${project.build.finalName}/WEB-INF/classes</outputDirectory>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <version>3.1</version>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-war-plugin</artifactId>
                <version>2.4</version>
                <configuration>
                    <webXml>${project.build.directory}/generated-sources/appengine-endpoints/WEB-INF/web.xml</webXml>
                    <webResources>
                        <resource>
                            <!-- this is relative to the pom.xml directory -->
                            <directory>${project.build.directory}/generated-sources/appengine-endpoints</directory>
                            <!-- the list has a default value of ** -->
                            <includes>
                                <include>WEB-INF/*.discovery</include>
                                <include>WEB-INF/*.api</include>
                            </includes>
                        </resource>
                    </webResources>
                </configuration>
            </plugin>
            <plugin>
                <groupId>com.google.appengine</groupId>
                <artifactId>appengine-maven-plugin</artifactId>
                <version>1.9.4</version>
                <configuration>
                    <enableJarClasses>false</enableJarClasses>
                    <!-- Comment in the below snippet to bind to all IPs instead of just localhost -->
                    <!-- address>0.0.0.0</address>
                    <port>8080</port -->
                    <!-- Comment in the below snippet to enable local debugging with a remove debugger
                         like those included with Eclipse or IntelliJ -->
                    <!-- jvmFlags>
                      <jvmFlag>-agentlib:jdwp=transport=dt_socket,address=8000,server=y,suspend=n</jvmFlag>
                    </jvmFlags -->
                </configuration>                
                <executions>
                    <execution>
                        <goals>
                            <goal>endpoints_get_discovery_doc</goal>
                        </goals>
                    </execution>
                </executions>

            </plugin>
        </plugins>
    </build>

</project>

这里是java和maven版本信息

Apache Maven 3.2.3 (33f8c3e1027c3ddde99d3cdebad2656a31e8fdf4; 2014-08-12T02:28:10+05:30)
Maven home: /usr/local/Cellar/maven/3.2.3/libexec
Java version: 1.8.0_20, vendor: Oracle Corporation
Java home: /Library/Java/JavaVirtualMachines/jdk1.8.0_20.jdk/Contents/Home/jre
Default locale: en_US, platform encoding: UTF-8
OS name: "mac os x", version: "10.10", arch: "x86_64", family: "mac"

这个问题不同于 How to set specific java version to Maven

我只安装了 1 个版本的 java，即 JDK 8

这是我在终端中运行的命令，使 maven 使用最新的 java 版本

export JAVA_HOME=$(/usr/libexec/java_home)

Answer 1

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile (default-compile) on project helloworld: Fatal error compiling: invalid target release: 1.7 -> [Help 1]

如果您查看该错误，它会提示 JDK7。确保您使用正确版本的 Java 才能编译应用程序。您至少需要jdk1.7(或更高版本)。

由于问题被标记为 eclipse，您还可以在 eclipse 内的“已安装的 JRE”选项中设置可用的 java 编译器

除此之外，您还可以在项目的 pom 中设置合规级别，如下所示

        <plugin>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.1</version>
            <configuration>
                <source>1.7</source> <!-- or 1.8 -->
                <target>1.7</target> <!-- or 1.8 -->
            </configuration>
        </plugin>