本篇内容介绍了“HBase中怎么将已知表移植到另一张表中”的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！
将已经存在某张表，比如 blog，将此表中的数据“移植”到另外一张新表中。
/** * 将HBase中一张表的数据移植到另一张表中。 * */public class HBaseAndMapReduce4 {public static void main(String[] args) throws Exception {System.exit(run());}public static int run() throws Exception {Configuration conf = new Configuration();conf = HBaseConfiguration.create(conf);conf.set(\”hbase.zookeeper.quorum\”, \”192.168.226.129\”);Job job = Job.getInstance(conf, \”findFriend\”);job.setJarByClass(HBaseAndMapReduce4.class);//实例化scan对象。Scan scan = new Scan();scan.addColumn(Bytes.toBytes(\”article\”), Bytes.toBytes(\”tags\”));scan.addColumn(Bytes.toBytes(\”author\”), Bytes.toBytes(\”nickname\”));TableMapReduceUtil.initTableMapperJob(\”blog\”, scan, FindFriendMapper.class, ImmutableBytesWritable.class, ImmutableBytesWritable.class,job);TableMapReduceUtil.initTableReducerJob(\”friend02\”, FindFriendReducer.class, job);checkTable(conf);return job.waitForCompletion(true) ? 0 : 1;}private static void checkTable(Configuration conf) throws Exception {Connection con = ConnectionFactory.createConnection(conf);Admin admin = con.getAdmin();TableName tn = TableName.valueOf(\”friend02\”);if (!admin.tableExists(tn)){HTableDescriptor htd = new HTableDescriptor(tn);HColumnDescriptor hcd = new HColumnDescriptor(\”person\”);htd.addFamily(hcd);admin.createTable(htd);System.out.println(\”表不存在，新创建表成功….\”);}}public static class FindFriendMapper extends TableMapper<ImmutableBytesWritable, ImmutableBytesWritable>{@Override//key是hbase中的行键//value是hbase中的所行键的所有数据protected void map(ImmutableBytesWritable key,Result value,Mapper<ImmutableBytesWritable, Result,ImmutableBytesWritable, ImmutableBytesWritable>.Context context)throws IOException, InterruptedException {ImmutableBytesWritable v = null;String[] kStrs = null;List<Cell> cs = value.listCells();for (Cell cell : cs) {if (\”tags\”.equals(Bytes.toString(CellUtil.cloneQualifier(cell)))){kStrs = Bytes.toString(CellUtil.cloneValue(cell)).split(\”,\”);}else if (\”nickname\”.equals(Bytes.toString(CellUtil.cloneQualifier(cell)))){v = new ImmutableBytesWritable(CellUtil.cloneValue(cell));}}for (String kStr : kStrs) {context.write(new ImmutableBytesWritable(Bytes.toBytes(kStr.toLowerCase())), v);}}}public static class FindFriendReducer extendsTableReducer<ImmutableBytesWritable, ImmutableBytesWritable, ImmutableBytesWritable> {@Overrideprotected void reduce(ImmutableBytesWritable key,Iterable<ImmutableBytesWritable> values,Reducer<ImmutableBytesWritable, ImmutableBytesWritable, ImmutableBytesWritable, Mutation>.Context context)throws IOException, InterruptedException {System.out.println( \”key—>\” key.get() );Put put = new Put(key.get());StringBuilder vStr = new StringBuilder();for (ImmutableBytesWritable value : values) {System.out.println( \”value–>\” value.get() );vStr.append((vStr.length() > 0 ? \”,\”:\”\”) Bytes.toString(value.get()));}put.addColumn(Bytes.toBytes(\”person\”), Bytes.toBytes(\”nickname\”),Bytes.toBytes(vStr.toString()));context.write(key, put);}}}
“HBase中怎么将已知表移植到另一张表中”的内容就介绍到这里了，感谢大家的阅读。如果想了解更多行业相关的知识可以关注西部数码网站，小编将为大家输出更多高质量的实用文章！
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