Hive（二）：获取HiveConnection，及重现获取过程中的某些问题。

一：未创建Maven工程，所需jar包都是自己一一找的，结果碰到许多缺包问题，最后我的lib下包为：

二：尝试获取HiveConnection，先附上成功获取HiveConnection的代码：

public class Test01Hive {

	private static String driverName = "org.apache.hive.jdbc.HiveDriver";  
	private static String url = "jdbc:hive2://master:10000/default";  
	private static String user = "hive";  
	private static String password = "xujun";  

	public static void main(String[] args) throws Exception {  
		Class.forName(driverName);  
		Connection conn = DriverManager.getConnection(url, user, password);  
		// org.apache.hive.jdbc.HiveConnection@ebe538
		System.out.println(   conn );
	}  
}

问题重现1：

开始定义的 url = "jdbc:hive://master:10000/default";  结果报如下错误：

java.sql.SQLException: No suitable driver found for jdbc:hive://master:10000/default
    at java.sql.DriverManager.getConnection(DriverManager.java:596)
    at java.sql.DriverManager.getConnection(DriverManager.java:215)
    at com.berg.hive.test1.api.Test01Hive.getConn(Test01Hive.java:50)
    at com.berg.hive.test1.api.Test01Hive.main(Test01Hive.java:37)

问题1解决：

将url更改为： url = "jdbc:hive2://master:10000/default";  

问题1解决思路来源:

http://stackoverflow.com/questions/33722139/java-sql-sqlexception-no-suitable-driver-found-for-jdbchive-localhost10000  

问题重现2：

org.apache.hive.service.cli.HiveSQLException: Failed to open new session:
java.lang.RuntimeException: org.apache.hadoop.ipc.RemoteException
(org.apache.hadoop.security.authorize.AuthorizationException): User: hadoop is not allowed to  impersonate hive
    at org.apache.hive.jdbc.Utils.verifySuccess(Utils.java:258)
    at org.apache.hive.jdbc.Utils.verifySuccess(Utils.java:249)
    at org.apache.hive.jdbc.HiveConnection.openSession(HiveConnection.java:579)
    at org.apache.hive.jdbc.HiveConnection.<init>(HiveConnection.java:167)
    at org.apache.hive.jdbc.HiveDriver.connect(HiveDriver.java:107)
    at java.sql.DriverManager.getConnection(DriverManager.java:571)
    at java.sql.DriverManager.getConnection(DriverManager.java:215)
    at com.berg.hive.test1.api.Test01Hive.getConn(Test01Hive.java:50)
    at com.berg.hive.test1.api.Test01Hive.main(Test01Hive.java:38)
Caused by: org.apache.hive.service.cli.HiveSQLException: Failed to open new session:
java.lang.RuntimeException: org.apache.hadoop.ipc.RemoteException
(org.apache.hadoop.security.authorize.AuthorizationException): User: hadoop is not allowed to
impersonate hive

问题2解决：进入hadoop安装目录下，然后切换至etc/hadoop即hadoop-2.6.4/etc/hadoop，修改core-site.xml中文件内容，在原文件内容中添加：

    <property>
        <name>hadoop.proxyuser.hadoop.hosts</name>                                               
        <value>*</value>
    </property>

    <property>
            <name>hadoop.proxyuser.hadoop.groups</name>
            <value>*</value>
    </property>

我的修改后是：

<configuration>
	<property> 
        	<name>fs.defaultFS</name> 
        	<value>hdfs://master:9000</value> 
    	</property> 
    	<property> 
        	<name>hadoop.tmp.dir</name> 
        	<value>file:/mysoftware/hadoop-2.6.4/tmp</value>
    	</property>
    	<property>
        	<name>hadoop.native.lib</name>
        	<value>false</value>
    	</property>

	<property>
		<name>hadoop.proxyuser.hadoop.hosts</name>                                               
        	<value>*</value>
	</property>

	<property>
        	<name>hadoop.proxyuser.hadoop.groups</name>
        	<value>*</value>
	</property>

</configuration>

问题2思路解决来源：
http://stackoverflow.com/questions/16582126/getting-e0902-exception-occured-user-oozie-is-not-allowed-to-impersonate-ooz

另外几个链接：

1. 重启mysql服务：

http://wwwlouxuemingcom.blog.163.com/blog/static/209747822013411103950266/

2. Could not open connection to jdbc

http://stackoverflow.com/questions/31150678/java-sql-sqlexception-could-not-open-connection-to-jdbchive2-localhost10000

3.Unable to instantiate org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient

http://stackoverflow.com/questions/35449274/java-lang-runtimeexception-unable-to-instantiate-org-apache-hadoop-hive-ql-meta

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