学步园

1、java.lang.NoClassDefFoundError: org/apache/hadoop/hbase/HBaseConfiguration 

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/hadoop/hbase/HBaseConfiguration
        at org.apache.gora.hbase.store.HBaseStore.initialize(HBaseStore.java:108)
        at org.apache.gora.store.DataStoreFactory.initializeDataStore(DataStoreFactory.java:102)
        at org.apache.gora.store.DataStoreFactory.createDataStore(DataStoreFactory.java:161)
        at org.apache.gora.store.DataStoreFactory.createDataStore(DataStoreFactory.java:135)
        at org.apache.nutch.storage.StorageUtils.createWebStore(StorageUtils.java:75)
        at org.apache.nutch.crawl.InjectorJob.run(InjectorJob.java:221)
        at org.apache.nutch.crawl.Crawler.runTool(Crawler.java:68)
        at org.apache.nutch.crawl.Crawler.run(Crawler.java:136)
        at org.apache.nutch.crawl.Crawler.run(Crawler.java:250)
        at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
        at org.apache.nutch.crawl.Crawler.main(Crawler.java:257)
Caused by: java.lang.ClassNotFoundException: org.apache.hadoop.hbase.HBaseConfiguration
        at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
        ... 11 more

官方文档说明如下：

N.B. It's possible to encounter the following exception: java.lang.NoClassDefFoundError: org/apache/hadoop/hbase/HBaseConfiguration; this is caused by the fact that sometimes the hbase TEST jar is deployed in the lib dir. To resolve this just copy the lib over from your installed HBase dir into the build lib dir. (This issue is currently in progress).

解决方法：

我们把$HBASE_HOME/lib下的所有包，拷贝到$NUTCH_HOME/runtime/local/lib目录下。运行即可

2、java.lang.NoSuchMethodError:org.apache.hadoop.hbase.HColumnDescriptor.setMaxVersions(I)V

HBASE官方JIRA BUG编号：HBASE-8273

这个是HBASE-5357引入的问题，原因是HBASE-5357将HColumnDescriptor.setMaxVersions
返回值修改成返回​​HColumnDescriptor，而不是返回void，所以改变了​​HColumnDescriptor setMaxVersions
方法的签名。所以它只会得到与Integer.intValue编译仍然不会找到setMaxVersions（INT）

Cloudera 官网说明

Column family manipulations are binary-incompatible between CDH4.2 and CDH4.0/CDH4.1
Because of HBASE-5357, code compiled against CDH4.0 and CDH4.1 will fail with java.lang.NoSuchMethodError: org.apache.hadoop.hbase.HColumnDescriptor.setMaxVersions(I)V, if used with the CDH4.2 libraries. The reason is that the setter methods in HColumnDescriptor were modified to return HColumnDescriptor instead of void, which changes their signature. Code that only does data manipulations, using the HTable class, will still work without recompilation.

Bug: HBASE-8273

Severity: Medium

Anticipated Resolution: None planned; use workaround.

Workaround: Code compiled against CDH4.0 and 4.1 that uses HColumnDescriptor must be recompiled against CDH4.2 in order to work with the CDH4.2 libraries. Code compiled against CDH4.0 and CDH4.1 running with those libraries does not have this problem.

原因：这边我使用的hadoop和hbase启动是没有问题的，也就是说是gora-hbase插件的问题

解决方法：

将gora-hbase插件中涉及使用到HColumnDescriptor的代码重新编译可解决。

具体要编译那些类后续会列出

3、java.lang.ClassNotFoundException: org.apache.gora.hbase.store.HBaseStore

hadoop@nutch1:/data/projects/apache-nutch-2.2.1/runtime/local$ bin/nutch crawl urls/seed.txt -dir crawl -depth 3 -topN 5
Exception in thread "main" java.lang.ClassNotFoundException: org.apache.gora.hbase.store.HBaseStore
        at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:188)
        at org.apache.nutch.storage.StorageUtils.getDataStoreClass(StorageUtils.java:89)
        at org.apache.nutch.storage.StorageUtils.createWebStore(StorageUtils.java:73)
        at org.apache.nutch.crawl.InjectorJob.run(InjectorJob.java:221)
        at org.apache.nutch.crawl.Crawler.runTool(Crawler.java:68)
        at org.apache.nutch.crawl.Crawler.run(Crawler.java:136)
        at org.apache.nutch.crawl.Crawler.run(Crawler.java:250)
        at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
        at org.apache.nutch.crawl.Crawler.main(Crawler.java:257)

解决方法：

方法1：下载gora-0.3，然后对该目录下的gora-hbase进行编译生成gora-hbase.jar，然后将jar包放到$NUTCH/runtime/local/lib目录下

方法2：修改$NUTCH_HOME/ivy/ivy.xml

将<dependency org="org.apache.gora" name="gora-hbase"
rev="0.3" conf="*->default" />去掉注释。然后再重新编译一次。这样ivy会为你生成gora-hbase的插件

4、java.lang.NullPointerException

 java.lang.NullPointerException
at org.apache.avro.util.Utf8.<init>(Utf8.java:37)
at org.apache.nutch.crawl.GeneratorReducer.setup(GeneratorReducer.java:100)
at org.apache.hadoop.mapreduce.Reducer.run(Reducer.java:174)
at org.apache.hadoop.mapred.ReduceTask.runNewReducer(ReduceTask.java:649)
at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:418)
at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:398)

修改GeneratorJob中的public Map<String,Object> run(Map<String,Object> args) 方法。

添加以下三行

 // generate batchId
    int randomSeed = Math.abs(new Random().nextInt());
    String batchId = (curTime / 1000) + "-" + randomSeed;
    getConf().set(BATCH_ID, batchId);