Maven引入Hadoop依赖报错：Missing artifact jdk.tools:jdk.tools:jar:1.6

<dependency>  
    <groupId>org.apache.hadoop</groupId>  
    <artifactId>hadoop-mapreduce-client-core</artifactId>  
    <version>2.4.0</version>  
    <exclusions>  
        <exclusion>  
            <groupId>jdk.tools</groupId>  
            <artifactId>jdk.tools</artifactId>  
        </exclusion>  
    </exclusions>  
</dependency>
########################添加一下一段代码即可#################################  
<dependency>  
    <groupId>jdk.tools</groupId>  
    <artifactId>jdk.tools</artifactId>  
    <version>1.6</version>  
    <scope>system</scope>  
    <systemPath>${JAVA_HOME}/lib/tools.jar</systemPath>  
</dependency>