启动hive时出现：Unable to instantiate org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient

Exception in thread "main" java.lang.RuntimeException: 
java.lang.RuntimeException: Unable to instantiate 
org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient
         at 
org.apache.hadoop.hive.ql.session.SessionState.start(SessionState.java:449)
         at org.apache.hadoop.hive.cli.CliDriver.run(CliDriver.java:634)
         at org.apache.hadoop.hive.cli.CliDriver.main(CliDriver.java:578)
         at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
         at 
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
         at 
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
         at java.lang.reflect.Method.invoke(Method.java:601)
         at org.apache.hadoop.util.RunJar.main(RunJar.java:212)
Caused by: java.lang.RuntimeException: Unable to instantiate 
org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient
         at 
org.apache.hadoop.hive.metastore.MetaStoreUtils.newInstance(MetaStoreUtils.java:1481)
         at 
org.apache.hadoop.hive.metastore.RetryingMetaStoreClient.(RetryingMetaStoreClient.java:64)
         at 
org.apache.hadoop.hive.metastore.RetryingMetaStoreClient.getProxy(RetryingMetaStoreClient.java:74)
         at 
org.apache.hadoop.hive.ql.metadata.Hive.createMetaStoreClient(Hive.java:2674)
         at org.apache.hadoop.hive.ql.metadata.Hive.getMSC(Hive.java:2693)
         at 
org.apache.hadoop.hive.ql.session.SessionState.start(SessionState.java:430)
         ... 7 more

解决方法：

网上对于这个问题的答案是众说纷纭，我也尝试了网上所说的各种办法可是问题依旧，我试着更换MySQL版本，错误继续、试着升级hive错误继续、修改配置文件，错误继续、总之试了很多方法还是不行。。。

于是想到我的hadoop版本是1.2.1，而用的hive第一次是1.0.1，第二次是1.2.1，这两次尝试均出现以上错误。所以试着把hive降级版本，选择了hive0.9.0，结果显示：

ok！成功了！果然是hive的版本过高导致的问题，所以其他伙伴有类似错误请考虑版本的问题！！