我正在尝试使用此命令运行Maven应用程序：
$mvn gwt:run
但访问http://127.0.0.1:8888/index.html
浏览器抛出HTTP错误503。
这是完整的POM，这可能是错的：
<?xml version="1.0" encoding="UTF-8"?>
<project
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>com.mygwtapp.app</groupId>
<artifactId>parent</artifactId>
<version>1.0.0-SNAPSHOT</version>
</parent>
<groupId>com.mygwtapp.app</groupId>
<artifactId>app</artifactId>
<version>1.0.0-SNAPSHOT</version>
<packaging>war</packaging>
<name>mygwtapp::App</name>
<properties>
<errai.version>4.0.0.Beta1</errai.version>
<gwt.version>2.8.0-beta1</gwt.version>
<slf4j.version>1.5.11</slf4j.version>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<javaee.version>1.0.2.Final</javaee.version>
<webappDirectory>src/main/webapp</webappDirectory>
</properties>
<!-- These must be here in this order because of missing guava-gwt snapshots in the JBoss Public Repository. -->
<repositories>
<repository>
<id>jboss</id>
<name>JBoss Public Repo</name>
<url>https://repository.jboss.org/nexus/content/groups/public</url>
</repository>
<repository>
<id>sonatype-public</id>
<name>Sonatype Public Snapshots Repo</name>
<url>https://oss.sonatype.org/content/repositories/public</url>
</repository>
</repositories>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.jboss.errai.bom</groupId>
<artifactId>errai-bom</artifactId>
<version>${errai.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava-gwt</artifactId>
<version>20.0-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>20.0-SNAPSHOT</version>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-user</artifactId>
<version>${gwt.version}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-dev</artifactId>
<version>${gwt.version}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.jboss.errai</groupId>
<artifactId>errai-javaee-all</artifactId>
</dependency>
<dependency>
<groupId>org.jboss.errai</groupId>
<artifactId>errai-cordova</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-elemental</artifactId>
<version>${gwt.version}</version>
</dependency>
<dependency>
<groupId>com.googlecode.gwtquery</groupId>
<artifactId>gwtquery</artifactId>
<version>1.5-beta1</version>
</dependency>
<dependency>
<groupId>org.jboss.spec</groupId>
<artifactId>jboss-javaee-7.0</artifactId>
<version>${javaee.version}</version>
<type>pom</type>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.2</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.jboss.errai</groupId>
<artifactId>errai-cdi-jboss</artifactId>
</dependency>
<dependency>
<groupId>org.jboss.errai</groupId>
<artifactId>errai-cdi-server</artifactId>
</dependency>
<dependency>
<groupId>com.mygwtapp.app</groupId>
<artifactId>services</artifactId>
<version>1.0.0-SNAPSHOT</version>
</dependency>
</dependencies>
<build>
<finalName>${project.artifactId}</finalName>
<outputDirectory>${webappDirectory}/WEB-INF/classes</outputDirectory>
<resources>
<resource>
<directory>src/main/java</directory>
</resource>
<resource>
<directory>src/main/resources</directory>
</resource>
</resources>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.eclipse.m2e</groupId>
<artifactId>lifecycle-mapping</artifactId>
<version>1.0.0</version>
<configuration>
<lifecycleMappingMetadata>
<pluginExecutions>
<pluginExecution>
<pluginExecutionFilter>
<groupId>org.codehaus.mojo</groupId>
<artifactId>gwt-maven-plugin</artifactId>
<versionRange>[2.4.0,)</versionRange>
<goals>
<goal>resources</goal>
</goals>
</pluginExecutionFilter>
<action>
<skip />
</action>
</pluginExecution>
<pluginExecution>
<pluginExecutionFilter>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<versionRange>[2.1,)</versionRange>
<goals>
<goal>unpack</goal>
</goals>
</pluginExecutionFilter>
<action>
<ignore></ignore>
</action>
</pluginExecution>
</pluginExecutions>
</lifecycleMappingMetadata>
</configuration>
</plugin>
</plugins>
</pluginManagement>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>gwt-maven-plugin</artifactId>
<version>${gwt.version}</version>
<executions>
<execution>
<goals>
<goal>compile</goal>
</goals>
</execution>
</executions>
<configuration>
<logLevel>INFO</logLevel>
<noServer>false</noServer>
<extraJvmArgs>-Xmx2048m -XX:CompileThreshold=7000</extraJvmArgs>
<disableCastChecking>true</disableCastChecking>
<runTarget>index.html</runTarget>
<draftCompile>true</draftCompile>
<optimizationLevel>0</optimizationLevel>
<style>PRETTY</style>
<hostedWebapp>${webappDirectory}</hostedWebapp>
<strict>true</strict>
</configuration>
<dependencies>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-user</artifactId>
<version>${gwt.version}</version>
</dependency>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-dev</artifactId>
<version>${gwt.version}</version>
</dependency>
</dependencies>
</plugin>
<plugin>
<artifactId>maven-clean-plugin</artifactId>
<version>2.4.1</version>
<configuration>
<filesets>
<fileset>
<directory>${basedir}</directory>
<includes>
<include>src/main/webapp/app/</include>
<include>src/main/webapp/WEB-INF/deploy/</include>
<include>src/main/webapp/WEB-INF/lib/</include>
<include>**/gwt-unitCache/**</include>
<include>.errai/</include>
</includes>
</fileset>
</filesets>
</configuration>
</plugin>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<plugin>
<artifactId>maven-war-plugin</artifactId>
<version>2.2</version>
<executions>
<execution>
<phase>compile</phase>
<goals>
<goal>exploded</goal>
</goals>
</execution>
</executions>
<configuration>
<webappDirectory>${webappDirectory}</webappDirectory>
</configuration>
</plugin>
</plugins>
</build>
</project>