hbase - 我在运行 hbase 客户端时遇到此异常

Question

import java.io.IOException;

import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.ResultScanner;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.util.Bytes;



public class HBaseExample {
  public static void main(String[] args) throws IOException {

    HBaseConfiguration config = new HBaseConfiguration();

    HTable table = new HTable(config, "myLittleHBaseTable");



    Put p = new Put(Bytes.toBytes("myLittleRow"));

    p.add(Bytes.toBytes("myLittleFamily"), Bytes.toBytes("someQualifier"),
      Bytes.toBytes("Some Value"));


    table.put(p);

    Get g = new Get(Bytes.toBytes("myLittleRow"));
    Result r = table.get(g);
    byte [] value = r.getValue(Bytes.toBytes("myLittleFamily"),
      Bytes.toBytes("someQualifier"));

    String valueStr = Bytes.toString(value);
    System.out.println("GET: " + valueStr);

    Scan s = new Scan();
    s.addColumn(Bytes.toBytes("myLittleFamily"), Bytes.toBytes("someQualifier"));
    ResultScanner scanner = table.getScanner(s);
    try {
ult instances.
      // Now, for the actual iteration. One way is to use a while loop like so:
      for (Result rr = scanner.next(); rr != null; rr = scanner.next()) {
        // print out the row we found and the columns we were looking for
        System.out.println("Found row: " + rr);
      }


    } finally {
 clause
      scanner.close();
    }
  }
}

Caused by: java.lang.ClassNotFoundException: HBaseExample
    at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
    at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
Could not find the main class: HBaseExample.  Program will exit.

Answer 1

您如何运行此测试？运行时，您需要确保 Hadoop 和 HBase jar 都在您的类路径中。例如，我建议在 Hadoop 上下文中运行它

/usr/local/hadoop/bin/hadoop jar YourJar.jar

您的问题很可能与类路径相关。