Examples of using HBase Java APIs

Through the use of HBase APIs, the following example shows common operations on HBase, as shown below:

2. PackageNet. bkjia. www;
5. ImportOrg. apache. Hadoop. conf. Configuration;
6. ImportOrg. apache. hadoop. hbase. HBaseConfiguration;
7. ImportOrg. apache. hadoop. hbase. HColumnDescriptor;
8. ImportOrg. apache. hadoop. hbase. HTableDescriptor;
9. ImportOrg. apache. hadoop. hbase. KeyValue;
10. ImportOrg. apache. hadoop. hbase. client. HBaseAdmin;
11. ImportOrg. apache. hadoop. hbase. client. HTable;
12. ImportOrg. apache. hadoop. hbase. client. Result;
13. ImportOrg. apache. hadoop. hbase. client. resultworkflow;
14. ImportOrg. apache. hadoop. hbase. client. Scan;
15. ImportOrg. apache. hadoop. hbase. io. BatchUpdate;
17. Public ClassHBaseDBDao {
19. // Define the configuration object HBaseConfiguration
20. StaticHBaseConfiguration cfg =Null;
21. Static{
22. Configuration configuration =NewConfiguration ();
23. Cfg =NewHBaseConfiguration (configuration );
24. }
26. // Create a table and specify the table name and column family.
27. Public Static VoidCreateTable (String tableName, String columnFarily)ThrowsException {
28. HBaseAdmin admin =NewHBaseAdmin (cfg );
29. If(Admin. tableExists (tableName )){
30. System. out. println (tableName +"Does not exist! ");
31. System. exit (0);
32. }Else{
33. HTableDescriptor tableDesc =NewHTableDescriptor (tableName );
34. TableDesc. addFamily (NewHColumnDescriptor (columnFarily +":"));
35. System. out. println ("Table created successfully! ");
36. }
37. }
39. // Add data through HTable. And BatchUpdate add data to an existing table
40. Public Static VoidAddData (String tableName, String row, String columnFamily, String column, String data)ThrowsException {
41. HTable table =NewHTable (cfg, tableName );
42. BatchUpdate update =NewBatchUpdate (row );
43. Update. put (columnFamily +":"+ Column, data. getBytes ());
44. Table. commit (update );
45. System. out. println ("Added successfully! ");
46. }
48. // Display all data. Use the HTable Scan class to obtain information about existing tables.
49. Public Static VoidGetAllData (String tableName)ThrowsException {
50. HTable table =NewHTable (cfg, tableName );
51. Scan scan =NewScan ();
52. Resultpartition rs = table. getpartition (scan );
53. For(Result r: rs ){
54. For(KeyValue kv: r. raw ()){
55. System. out. println (NewString (kv. getColumn () +NewString (kv. getValue ()));
56. }
57. }
58. }
60. // Test the Function
61. Public Static VoidMain (String [] args ){
62. Try{
63. String tableName ="Student";
64. HBaseDBDao. createTable (tableName,"C1");
65. HBaseDBDao. addData (tableName,"Row1","C1","1","This is row 1 column c1: c1");
66. HBaseDBDao. getAllData (tableName );
67. }Catch(Exception e ){
68. E. printStackTrace ();
69. }
70. }
71. }