在eclipse下编译hadoop2.0源码（补充篇：解决eclipse工程build时报错）

        在上文http://blog.youkuaiyun.com/dywywh709/article/details/21229075（在eclipse下编译hadoop2.0源码）中将maven工程编译成eclipse项目然后导入eclipse，但是细心的朋友会发现导入elipse后会报出各种各样的错误，通过努力本人解决了报的错误，与大家做一次分享，希望能共同进步。

     常见的错误及解决方案列举如下：

     

1. hadoop-streaming里面的build path有问题，显示/root/workspace/hadoop-2.2.0-src/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/conf(missing)

我个人认为这个问题可能是由于eclipse不支持跨model的文件引用。

解决办法：大家找到/root/workspace/hadoop-2.2.0-src/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/conf目录下capacity-scheduler.xml文件，将其copy至/root/workspace/hadoop-2.2.0-src/hadoop-tools/hadoop-streaming/dev-support目录下；然后打开/root/workspace/hadoop-2.2.0-src/hadoop-tools/hadoop-streaming目录下的pom.xml文件，找到如下位置：

        <directory>${basedir}/../../hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/conf</directory>

        将其修改为：

       <directory>${basedir}/hadoop-tools/hadoop-streaming/dev-support</directory>

至此，该问题解决。

2. /hadoop-common/src/test/java/org/apache/hadoop/io/serializer/avro/TestAvroSerialization.java显示没有AvroRecord类，在网上搜索到AvroRecord类放入到同级包中就行了。

       http://download.youkuaiyun.com/detail/dywywh709/7039179（此处可以下载该类）

3. org.apache.hadoop.ipc.protobuf包里面缺少两个类TestProtos.java,TestRpcServiceProtos.java.

      需要在/hadoop-common/target/generated-test-sources/java/org/apache/hadoop/ipc中找到profobuf拷贝到/hadoop-common/src/test/java中就好了

4. hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSClientFailover.java中报sun.net.spi.nameservice.NameService错误，这是一个需要import的包，存在于openjdk中，在Oracle Jdk中没找到，需要下载一个。NameService是一个接口，在网上找一个NameService放到该包中就好。 http://grepcode.com/file/repository.grepcode.com/java/root/jdk/openjdk/7u40-b43/sun/net/spi/nameservice/NameService.java#NameService

5. /hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/offlineEditsViewer/XmlEditsVisitor.java里面显示 
import com.sun.org.apache.xml.internal.serialize.OutputFormat; 
import com.sun.org.apache.xml.internal.serialize.XMLSerializer; 
失败.

这是由于Eclipse的强检查原则，打开Java -> Compiler -> Errors/Warnings and under "Deprecated and restricted API" change the setting of "Forbidden reference (access rules)" 将error级别调整到warning级别就好。

6. /hadoop-auth/org/apache/hadoop/security/authentication/client/AuthenricatorTestCase.java中显示server.start()和server.stop()错误，还没找到原因所在，待检查~~~(这里不影响编译及调试）

希望能解决大家遇到的一些错误，共同进步。