在HBase的，如何存储列表或数组结构

Question

我有一些数据，看起来像这样：

{“一个名”：“V1”，“V2”，“V3” ...] }

现在，我将存储到HBase中，列名是a-name，如何存储值（['v1'，'v2'，'v3'...]）？

Answer 1

HBase中的值只存储为一组字节，这意味着数组的序列化和反序列化是您的应用程序的责任。您可以使用Writables（请参阅下面的示例）手动执行此操作，或使用Avro/Thrift/JSON /等。序列化，反序列化数据

这里是你如何能做到这一个例子：

public class test { 
    public static Writable toWritable(ArrayList<String> list) { 
     Writable[] content = new Writable[list.size()]; 
     for (int i = 0; i < content.length; i++) { 
      content[i] = new Text(list.get(i)); 
     } 
     return new ArrayWritable(Text.class, content); 
    } 
    public static ArrayList<String> fromWritable(ArrayWritable writable) { 
     Writable[] writables = ((ArrayWritable) writable).get(); 
     ArrayList<String> list = new ArrayList<String>(writables.length); 
     for (Writable wrt : writables) { 
      list.add(((Text)wrt).toString()); 
     } 
     return list; 
    } 
    public static void main (String[] args) throws IOException { 
     ArrayList<String> arr = Lists.newArrayList("a", "b", "c"); 
     HTable table = new HTable(HBaseConfiguration.create(), "t1"); 
     Put p = new Put(Bytes.toBytes("key1")); 
     p.add(Bytes.toBytes("f1"), Bytes.toBytes("a"), WritableUtils.toByteArray(toWritable(arr))); 
     table.put(p); 
     Get g = new Get(Bytes.toBytes("key1")); 
     Result r = table.get(g); 
     ArrayWritable w = new ArrayWritable(Text.class); 
     w.readFields(
       new DataInputStream(
         new ByteArrayInputStream(
           r.getValue(Bytes.toBytes("f1"), Bytes.toBytes("a")) 
         ) 
       ) 
     ); 
     ArrayList<String> arr2 = fromWritable(w); 
     System.out.println(arr2.toString()); 
    } 
} 

下面是一些序列化更一般的代码/反序列化不同类型的成writables：https://github.com/elasticsearch/elasticsearch-hadoop/blob/master/mr/src/main/java/org/elasticsearch/hadoop/util/WritableUtils.java