HOW TO READ DATA FROM HBASE?

Derek Honeybun

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Points:119
Posted by  Derek Honeybun
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I'm use to SQL, but I need to read data from a HBase table. Any help on this would be great. A book or maybe just some sample code to read from the table. Someone said using a scanner would do the trick, but I do not know how to use it
  1. Mayank Tripathi

    Post:397

    Points:3117
    Re: How to read data from Hbase?


    // Sometimes, you won't know the row you're looking for. In this case, you
    // use a Scanner. This will give you cursor-like interface to the contents
    // of the table.  To set up a Scanner, do like you did above making a Put
    // and a Get, create a Scan.  Adorn it with column names, etc.
    Scan s = new Scan();
    s.addColumn(Bytes.toBytes("myLittleFamily"), Bytes.toBytes("someQualifier"));
    ResultScanner scanner = table.getScanner(s);
    try {
      // Scanners return Result 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);
      }
      // The other approach is to use a foreach loop. Scanners are iterable!
      // for (Result rr : scanner) {
      //   System.out.println("Found row: " + rr);
      // }
    } finally {
      // Make sure you close your scanners when you are done!
      // Thats why we have it inside a try/finally clause
      scanner.close();
    }

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