HBASE介绍

阳光穿透心脏的1/2处 2022-02-14 00:25 224阅读 0赞

Hbase  
基本使用方式  
hbase使用的方式需要在Linux环境下  
安装  
由于Linux出现问题无法远程连接 文件暂未安装。

创建表  
Java 使用方式  
第一步 实例化HBaseAdmin 这个类需要配置对象作为参数，因此初始化实例配置类传递此实例给HBaseAdmin.  
Configuration conf = HBaseConfiguration.create();  
HBaseAdmin admin = new HBaseAdmin(conf);  
第二步 创建TableDescriptor  
HTableDescriptor table = new HTableDescriptor(toBytes(“Table name”));  
HColumnDescriptor family = new HColumnDescriptor(toBytes(“column family”));  
table.addFamily(family);  
第三步 通过执行管理  
admin.createTable(table);

完整案例  
Configuration con =HBaseConfiguration.create();  
HBaseAdmin admin = new HBaseAdmin(con);

HTableDescriptor tableDescriptor = new TableDescriptor(TbaleName.valueOf(“emp”));  
tableDescriptor.addFamily(new HColumnDescriptor(“persona1”));  
tableDescriptor.addFamily(new HColumnDescriptor(“professiona1”));

Admin.createTable(tableDescriptor);  
System.out.println(“Table created”);

添加一列族到现有的表中  
Configuration conf = HBaseConfiguration.create();  
HBaseAdmin admin = new HBaseAdmin(conf);

HColumnDescriptor columnDescriptor =new HColumnDescriptor(“contactDetails”);  
Admin.addColumn(“employee”,columnDescriptor);  
System.out.println(“colomn added”);

从现有的表中删除列族  
Configuration conf = HBaseConfiguration.create();  
HBaseAdmin = new HBaseAdmin(conf);  
Admin.deleteColumn(“emplooyee”,”contactDetails”);  
System.out.println(“coloumn deleted”);  
验证HBase表的存在  
Configuration conf = HBaseConfiguration.create();  
HBaseAdmin admin = new HBaseAdmin(conf);  
Boolean bool = admin.tableExists(“emp”);  
System.out.println(bool);

删除HBase表  
Configuration conf = HBaseConfiguration.create();  
HBaseAdmin admin = new HBaseAdmin(conf);

admin.disableTable(“emp12”);  
admin.deleteTable(“emp12”);  
System.out.println(“Table deleted”);

关闭HBase  
Configuration conf = HBaseConfiguration.create();  
HBaseAdmin admin = new HBaseAdmin(conf);  
System.out.println(“Shutting down hbase”);  
admin.shutdown();

HBase表创建数据  
Configuration config = HBaseConfiguration.create();  
HTable hTable = new HTable(config,”emp”);  
Put p = new Put(Bytes.toBytes(“row1”));  
p.add(Bytes.toBytes(“personal”),Bytes.toBytes(“name”),Bytes.toBytes(“raju”));  
P.add(Bytes.toBytes(“professional”),Bytes.toBytes(“salary”),Bytes.toBytes(“50000”));  
hTable.put§;  
hTable.close();

HBase表更新数据  
Configuration conf = HBaseConfiguration.create();  
HTable hTable = new HTable(config,”emp”);  
Put p = new Put(Bytes.toBytes(“row1”));  
p.add(Bytes.toBytes(“personal”),Bytes.toBytes(“city”),Bytes.toBytes(“Delih”));  
hTable.put§;  
System.out.println(“ data Updated”);  
hTable.close();

从一个HBase表中读取值的完整程序  
Configuration config = HBaseConfiguration.create();  
HTable table = new HTable(config,”emp”);  
Get g = new Get(Bytes.toBytes(“row1”));  
Result result = table.get(g);  
byte\[\] value = result.getValue(Bytes.toBytes(“personal”),Bytes.toBytes(“name”));  
Byte\[\] vaklue1 = result.getValue(Bytes.toBytes(“personal”),Bytes.toBytes(“city”));

String name = Bytes.toString(value);  
String city = Bytes.toString(value1);  
System.out.println(“name:” + name +”city:”+city);

从HBase表中删除数据  
Configuration conf = HBaseConfiguration.create();  
HTable table = new HTable(conf,”employee”);  
Delete delete = new Delete(Bytes.toBytes(“row1”));  
delete.deleteColumn(Bytes.toBytes(“personal”),Bytes.toBytes(“name”));  
delete.deleteFamily(Bytes.toBytes(“professional”));

table.delete(delete);  
table.close();  
System.out.println(“data deleted…”);

使用Java API扫描整个表的数据  
Configuration conf = HBaseConfiguration.create();  
HTable table = new HTable(config,”emp”);  
Scan scan = new Scan();  
scan.addColumn(Bytes.toBytes(“personal”),Bytes.toBytes(“name”));  
Scan.addColumn(Bytes.toBytes(“personal”),Bytes.toBytes(“city”));  
ResultScanner scanner = table.getScanner(scan);  
for(Resultv result = scnner.next(); result != null; result = Scanner.next())  
System.out.println(“Found row:”+ result);  
Scanner.close();