我正在关注GWT和聚合物的以下教程：http://www.gwtproject.org/doc/latest/polymer-tutorial/introduction.html。现在我正在尝试创建todo项目。当我去运行项目（使用mvn gwt：run）时，我得到以下错误/堆栈跟踪：
[ERROR] Source level must be one of [auto, 1.8].
[ERROR] Google Web Toolkit 2.8.0
[ERROR] DevMode [-[no]startServer] [-port port-number | "auto"] [-logdir directory] [-logLevel (ERROR|WARN|INFO|TRACE|DEBUG|SPAM|ALL)] [-gen dir] [-bindAddress host-name-or-address] [-codeServerPort port-number | "auto"] [-[no]superDevMode] [-server servletContainerLauncher[:args]] [-startupUrl url] [-war dir] [-deploy dir] [-extra dir] [-modulePathPrefix ] [-workDir dir] [-XmethodNameDisplayMode (NONE|ONLY_METHOD_NAME|ABBREVIATED|FULL)] [-sourceLevel [auto, 1.8]] [-[no]generateJsInteropExports] [-[no]incremental] [-style (DETAILED|OBFUSCATED|PRETTY)] [-[no]failOnError] [-setProperty name=value,value...] module[s]
[ERROR]
[ERROR] where
[ERROR] -[no]startServer Starts a servlet container serving the directory specified by the -war flag. (defaults to ON)
[ERROR] -port Specifies the TCP port for the embedded web server (defaults to 8888)
[ERROR] -logdir Logs to a file in the given directory, as well as graphically
[ERROR] -logLevel The level of logging detail: ERROR, WARN, INFO, TRACE, DEBUG, SPAM or ALL (defaults to INFO)
[ERROR] -gen Debugging: causes normally-transient generated types to be saved in the specified directory
[ERROR] -bindAddress Specifies the bind address for the code server and web server (defaults to 127.0.0.1)
[ERROR] -codeServerPort Specifies the TCP port for the code server (defaults to 9997 for classic Dev Mode or 9876 for Super Dev Mode)
[ERROR] -[no]superDevMode Runs Super Dev Mode instead of classic Development Mode. (defaults to ON)
[ERROR] -server Specify a different embedded web server to run (must implement ServletContainerLauncher)
[ERROR] -startupUrl Automatically launches the specified URL
[ERROR] -war The directory into which deployable output files will be written (defaults to 'war')
[ERROR] -deploy The directory into which deployable but not servable output files will be written (defaults to 'WEB-INF/deploy' under the -war directory/jar, and may be the same as the -extra directory/jar)
[ERROR] -extra The directory into which extra files, not intended for deployment, will be written
[ERROR] -modulePathPrefix The subdirectory inside the war dir where DevMode will create module directories. (defaults empty for top level)
[ERROR] -workDir The compiler's working directory for internal use (must be writeable; defaults to a system temp dir)
[ERROR] -XmethodNameDisplayMode EXPERIMENTAL: Specifies method display name mode for chrome devtools: NONE, ONLY_METHOD_NAME, ABBREVIATED or FULL (defaults to NONE)
[ERROR] -sourceLevel Specifies Java source level (defaults to 1.8)
[ERROR] -[no]generateJsInteropExports Generate exports for JsInterop purposes (defaults to OFF)
[ERROR] -[no]incremental Compiles faster by reusing data from the previous compile. (defaults to ON)
[ERROR] -style Script output style: DETAILED, OBFUSCATED or PRETTY (defaults to OBFUSCATED)
[ERROR] -[no]failOnError Fail compilation if any input file contains an error. (defaults to OFF)
[ERROR] -setProperty Set the values of a property in the form of propertyName=value1[,value2...].
[ERROR] and
[ERROR] module[s] Specifies the name(s) of the module(s) to host
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 3.068 s
[INFO] Finished at: 2016-11-09T11:42:07-05:00
[INFO] Final Memory: 17M/230M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.codehaus.mojo:gwt-maven-plugin:2.8.0:run (default-cli) on project TodoList: Command [[
[ERROR] cmd.exe /X /C "C:\Promevo\jdk1.7.0_25\jre\bin\java -Xmx512m com.google.gwt.dev.DevMode -gen C:\Users\tyler.hilbert\Documents\TodoListApp\target\.generated -war C:\Users\tyler.hilbert\Documents\TodoListApp\target\TodoList-1.0-SNAPSHOT -logLevel INFO -port 8888 -codeServerPort 9997 -startupUrl TodoList.html -sourceLevel 1.7 org.gwtproject.tutorial.TodoList"
[ERROR] ]] failed with status -1
我的pom.xml文件如下所示：
<?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/maven-v4_0_0.xsd">
<!-- POM file generated with GWT webAppCreator -->
<modelVersion>4.0.0</modelVersion>
<groupId>org.gwtproject.tutorial</groupId>
<artifactId>TodoList</artifactId>
<packaging>war</packaging>
<version>1.0-SNAPSHOT</version>
<name>org.gwtproject.tutorial.TodoList</name>
<properties>
<!-- Convenience property to set the GWT version -->
<gwtVersion>2.8.0</gwtVersion>
<!-- Note: GWT needs at least java 1.6 -->
<maven.compiler.source>1.7</maven.compiler.source>
<maven.compiler.target>1.7</maven.compiler.target>
</properties>
<dependencyManagement>
<dependencies>
<!-- ensure all GWT deps use the same version (unless overridden) -->
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt</artifactId>
<version>${gwtVersion}</version>
<scope>import</scope>
<type>pom</type>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-servlet</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-user</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-dev</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-codeserver</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/com.vaadin.polymer/vaadin-gwt-polymer-elements -->
<dependency>
<groupId>com.vaadin.polymer</groupId>
<artifactId>vaadin-gwt-polymer-elements</artifactId>
<version>1.7.0.0</version>
</dependency>
</dependencies>
<build>
<plugins>
<!-- GWT Maven Plugin -->
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>gwt-maven-plugin</artifactId>
<version>${gwtVersion}</version>
<executions>
<execution>
<goals>
<goal>compile</goal>
</goals>
</execution>
<execution>
<!-- Run tests through gwt:test, this allows reusing the plugin configuration
for GWTTestCases -->
<id>gwt-tests</id>
<phase>test</phase>
<goals>
<goal>test</goal>
</goals>
</execution>
</executions>
<!-- Plugin configuration. There are many available options, see gwt-maven-plugin
documentation at codehaus.org -->
<configuration>
<jsInteropMode>JS</jsInteropMode>
<modules>
<module>org.gwtproject.tutorial.TodoList</module>
</modules>
<!-- URL that should be opened by DevMode (gwt:run). -->
<runTarget>TodoList.html</runTarget>
<!-- Ask GWT to create the Story of Your Compile (SOYC) (gwt:compile) -->
<compileReport>true</compileReport>
<!-- Run tests using HtmlUnit -->
<mode>htmlunit</mode>
<!-- Tests patterns -->
<includes>**/Test*.java,**/*Test.java,**/*TestCase.java</includes>
</configuration>
</plugin>
<!-- Skip normal test execution, we use gwt:test instead -->
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.17</version>
<configuration>
<skip>true</skip>
</configuration>
</plugin>
<!-- NOTE: this is only needed if you use "mvn eclipse:eclipse". -->
<!-- You can remove this plugin if you intend to only use the Maven integration
in Eclipse, or another IDE -->
<plugin>
<artifactId>maven-eclipse-plugin</artifactId>
<version>2.7</version> <!-- Note 2.8 does not work with AspectJ aspect path -->
<configuration>
<downloadSources>true</downloadSources>
<downloadJavadocs>false</downloadJavadocs>
<wtpversion>2.0</wtpversion>
<additionalBuildcommands>
<buildCommand>
<name>com.google.gwt.eclipse.core.gwtProjectValidator</name>
</buildCommand>
</additionalBuildcommands>
<additionalProjectnatures>
<projectnature>com.google.gwt.eclipse.core.gwtNature</projectnature>
</additionalProjectnatures>
</configuration>
</plugin>
</plugins>
</build>
</project>
如何正确运行项目？
答案 0 :(得分：0)
我改变了以下几行：
<maven.compiler.source>1.7</maven.compiler.source>
<maven.compiler.target>1.7</maven.compiler.target>
到此并且它自行修复：
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>