MapReduce服务 MRS-创建HBase表:代码样例

时间：2025-02-12 14:58:43

MapReduce服务 MRS

代码样例

以下代码片段在com.huawei.bigdata.hbase.examples包的“HBaseExample”类的testCreateTable方法中。

public void testCreateTable() {     LOG .info("Entering testCreateTable: " + tableName);     // Set the column family name to info.     byte [] fam = Bytes.toBytes("info");     ColumnFamilyDescriptor familyDescriptor = ColumnFamilyDescriptorBuilder.newBuilder(fam)             // Set data encoding methods. HBase provides DIFF,FAST_DIFF,PREFIX             // HBase 2.0 removed `PREFIX_TREE` Data Block Encoding from column families.             .setDataBlockEncoding(DataBlockEncoding.FAST_DIFF)             // Set compression methods, HBase provides two default compression             // methods:GZ and SNAPPY             // GZ has the highest compression rate,but low compression and             // decompression effeciency,fit for cold data             // SNAPPY has low compression rate, but high compression and             // decompression effeciency,fit for hot data.             // it is advised to use SANPPY             .setCompressionType(Compression.Algorithm.SNAPPY)             .build();     TableDescriptor htd = TableDescriptorBuilder.newBuilder(tableName).setColumnFamily(familyDescriptor).build();     Admin admin = null;     try {         // Instantiate an Admin object.         admin = conn.getAdmin();         if (!admin.tableExists(tableName)) {             LOG.info("Creating table...");             admin.createTable(htd);             LOG.info(admin.getClusterMetrics());             LOG.info(admin.listNamespaceDescriptors());             LOG.info("Table created successfully.");         } else {             LOG.warn("table already exists");         }     } catch (IOException e) {         LOG.error("Create table failed.", e);     } finally {         if (admin != null) {             try {                 // Close the Admin object.                 admin.close();             } catch (IOException e) {                 LOG.error("Failed to close admin ", e);             }         }     }     LOG.info("Exiting testCreateTable.");}

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