xmlns =「http://maven.apache.org/POM/4.0.0」URI未註冊

我想構建一個安卓應用程序maven。使用this tutorial我創建這個代號爲pom.xml一個XML文件：xmlns =「http://maven.apache.org/POM/4.0.0」URI未註冊

<?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"> 
    <modelVersion>4.0.0</modelVersion> 
    <groupId>org.hello</groupId> 
    <artifactId>gs-maven-android</artifactId> 
    <version>0.1.0</version> 
    <packaging>apk</packaging> 

    <properties> 
     <!-- use UTF-8 for everything --> 
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> 
     <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> 
    </properties> 

    <dependencies> 
     <dependency> 
      <groupId>com.google.android</groupId> 
      <artifactId>android</artifactId> 
      <version>4.1.1.4</version> 
      <scope>provided</scope> 
     </dependency> 
    </dependencies> 

    <build> 
     <plugins> 
      <plugin> 
       <groupId>com.jayway.maven.plugins.android.generation2</groupId> 
       <artifactId>android-maven-plugin</artifactId> 
       <version>3.9.0-rc.1</version> 
       <configuration> 
        <sdk> 
         <platform>19</platform> 
        </sdk> 
        <deleteConflictingFiles>true</deleteConflictingFiles> 
        <undeployBeforeDeploy>true</undeployBeforeDeploy> 
       </configuration> 
       <extensions>true</extensions> 
      </plugin> 
      <plugin> 
       <artifactId>maven-compiler-plugin</artifactId> 
       <version>3.1</version> 
       <configuration> 
        <source>1.6</source> 
        <target>1.6</target> 
       </configuration> 
      </plugin> 
     </plugins> 
    </build> 

</project>

但在 xmlns="http://maven.apache.org/POM/4.0.0" 和 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd" 我有錯誤：