从Java客户端连接Hive时出现ClassNotFoundException

在Java客户端中，我试图通过Hive中的表执行查询。执行查询时，程序按照以下详细说明引发java.lang.ClassNotFoundException。我在我的类路径中有hadoop-core-1.0.4.jar。 Hive版本是0.12.0，hadoop版本是1.0.4。我无法解决问题。会是什么呢？以下是代码片段和错误。从Java客户端连接Hive时出现ClassNotFoundException

public static String getDummyData() { 
    String result = ""; 
    String driverName = "org.apache.hadoop.hive.jdbc.HiveDriver"; 
    try { 
     Class.forName(driverName); 
    } catch (ClassNotFoundException e) { 
     log.error("Could not find driver", e); 
    } 
    try { 
     Connection conn = DriverManager.getConnection("jdbc:hive://noon102:10000/default", "",""); 
     String tableName = "user"; 
     String query = "select * from " + tableName + " where id = ?"; 
     PreparedStatement ipMacSt = conn.prepareStatement(query); 
     ipMacSt.setInt(1, 6); 

     ResultSet res = ipMacSt.executeQuery(); 
     while (res.next()) { 
      result = result + res.getString(2) + "\n"; 
     } 
    } catch (Exception e) { 
    log.error("Could not execute the query", e); 
    } 

    return result; 
} 

Caused by: java.lang.NoClassDefFoundError: org/apache/hadoop/io/Writable 
     at org.apache.hadoop.hive.jdbc.HiveQueryResultSet.initSerde(HiveQueryResultSet.java:101) 
     at org.apache.hadoop.hive.jdbc.HiveQueryResultSet.<init>(HiveQueryResultSet.java:66) 
     at org.apache.hadoop.hive.jdbc.HiveStatement.executeQuery(HiveStatement.java:198) 
     at org.apache.hadoop.hive.jdbc.HiveStatement.execute(HiveStatement.java:132) 
     at org.apache.hadoop.hive.jdbc.HiveConnection.configureConnection(HiveConnection.java:133) 
     at org.apache.hadoop.hive.jdbc.HiveConnection.<init>(HiveConnection.java:122) 
     at org.apache.hadoop.hive.jdbc.HiveDriver.connect(HiveDriver.java:106) 
     at java.sql.DriverManager.getConnection(DriverManager.java:582) 
     at java.sql.DriverManager.getConnection(DriverManager.java:185) 
     at com.**.services.HadoopOperations.getDummyData(HadoopOperations.java:90) 
     ... 15 more 
Caused by: java.lang.ClassNotFoundException: org.apache.hadoop.io.Writable 
     at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:513) 
     at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:429) 
     at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:417) 
     at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:107) 
     at java.lang.ClassLoader.loadClass(ClassLoader.java:247) 
     ... 25 more

来源

2013-10-22 iargin

Plz显示您的代码或查询配置单元的方式。 – pensz

只是偶然发现了这一点，我有同样的问题，采用有3只Maven依赖固定它：

<dependency> 
    <groupId>org.apache.hadoop</groupId> 
    <artifactId>hadoop-core</artifactId> 
    <version>0.20.0</version> 
</dependency> 
<dependency> 
    <groupId>org.apache.hive</groupId> 
    <artifactId>hive-exec</artifactId> 
    <version>0.7.1</version> 
</dependency> 
<dependency> 
    <groupId>org.apache.hive</groupId> 
    <artifactId>hive-jdbc</artifactId> 
    <version>0.7.1</version> 
</dependency>

如果你不喜欢Maven的，刚刚从Maven的中央下载JAR文件存储库并将它们添加到您的构建路径。希望这也适用于你！

来源

2013-12-13 23:04:16 AlejandroVK

从Java客户端连接Hive时出现ClassNotFoundException

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