HBase客户端Java-API

HBase在存储数据时，没有数据类型！以字节数组存储
"cf".getBytes();
Bytes.toBytes("cf");

环境准备

（1）制作hbase的用户库，并导入
（2）导入hadoop用户库
（3）导入Junit测试库
（4）src目录中拷贝hdfs-site.xml、hbase-site.sh、regionservers、backup-masters4个文件，build source file.

HBaseDemo

public class HBaseDemo {
    HBaseAdmin admin;
    HTable htable;
    String TN = "phone"; // 表名

    @Before
    public void init() throws Exception {
        Configuration conf = new Configuration();
        // 设置zk配置信息，必须配置，否则无法定位
        conf.set("hbase.zookeeper.quorum", "node002,node003,node004");
        admin = new HBaseAdmin(conf);
        htable = new HTable(conf, TN.getBytes());
    }

    @Test
    public void creatTable() throws Exception {
        if (admin.tableExists(TN)) {
            admin.disableTable(TN);
            admin.deleteTable(TN);
            System.out.println("table exists!");
        }

        // 表描述
        HTableDescriptor desc = new HTableDescriptor(TableName.valueOf(TN));
        // 列族
        HColumnDescriptor cf = new HColumnDescriptor("cf".getBytes());
        desc.addFamily(cf);
        // 创建表
        admin.createTable(desc);
        System.out.println("create table success!");
    }

    @Test
    public void insertDB() throws Exception {
        String rowKey = "111111";
        Put put = new Put(rowKey.getBytes());
        put.add("cf".getBytes(), "name".getBytes(), "xiaohong".getBytes());
        put.add("cf".getBytes(), "age".getBytes(), "23".getBytes());
        put.add("cf".getBytes(), "sex".getBytes(), "women".getBytes());
        htable.put(put);
    }

    @Test
    public void getDB() throws Exception {
        String rowKey = "111111";
        Get get = new Get(rowKey.getBytes());
        // 获取指定的列，不指定的列不去查，开发必须写！不写是全部列！
        // 就像 select * 
        get.addColumn("cf".getBytes(), "name".getBytes());
        get.addColumn("cf".getBytes(), "age".getBytes());
        get.addColumn("cf".getBytes(), "sex".getBytes());
        Result rs = htable.get(get);

        Cell cell = rs.getColumnLatestCell("cf".getBytes(), "name".getBytes());
        Cell cell2 = rs.getColumnLatestCell("cf".getBytes(), "age".getBytes());
        Cell cell3 = rs.getColumnLatestCell("cf".getBytes(), "sex".getBytes());
        // System.out.println(new String(cell.getValue())); 过期了，用下面的工具类
        System.out.println(new String(CellUtil.cloneValue(cell)));
        System.out.println(new String(CellUtil.cloneValue(cell2)));
        System.out.println(new String(CellUtil.cloneValue(cell3)));
    }

    @Test
    public void scan() throws IOException {
        Scan scan = new Scan();
        ResultScanner scanner = htable.getScanner(scan);
  
        for (Result rs : scanner) {
            System.out.println("扫描结果: "+rs);
        }
    }
    
    @After
    public void destory() throws Exception {
        if (admin != null) {
            admin.close();
        }
    }
}

扫描结果: keyvalues={111111/cf:age/1543959930854/Put/vlen=2/mvcc=0, 111111/cf:name/1543959930854/Put/vlen=8/mvcc=0, 111111/cf:sex/1543959930854/Put/vlen=5/mvcc=0}