HBase客户端API

HBase客户端API

简单一点，先假定只操作table表，创建table对象

// 使用Admin对象来操作DDL
private static Admin admin;
// 使用Table对象来操作DML
private static Table table;

static {
    try {
        // 获取连接
        Connection conn = ConnectionFactory.createConnection();
        admin = conn.getAdmin();
        table = conn.getTable(TableName.valueOf("test"));
    } catch (IOException e) {
        e.printStackTrace();
    }
}

插入数据

先插入一条数据，来方便后续的查找操作

public static void testPut(String rowKey,String family,String q,String value) throws IOException {
    Put put = new Put(Bytes.toBytes(rowKey));

    put.addColumn(Bytes.toBytes(family),Bytes.toBytes(q),Bytes.toBytes(value));
    table.put(put);
}

testPut("123456","info","name","zs");

获取数据

正好来使用获取数据来验证一下上面是否成功插入了

public static void testGet(String rowKey,String family,String q) throws IOException {
    Get get = new Get(Bytes.toBytes(rowKey));

    get.addColumn(Bytes.toBytes(family),Bytes.toBytes(q));
    Result result = table.get(get);
    byte[] value = result.getValue(Bytes.toBytes(family), Bytes.toBytes(q));
    System.out.println(Bytes.toString(value));
}

testGet("123456","info","name");

删除数据

public static void testDelete(String rowKey,String family,String q) throws IOException {
    Delete delete = new Delete(Bytes.toBytes(rowKey));

    delete.addColumn(Bytes.toBytes(family),Bytes.toBytes(q));
    table.delete(delete);
}

testGet("123456","info","name");

过滤器

在使用get和scan查询数据时，可以添加过滤器来减少查询的数据量

public static void testScanWithFilter(String rowKey,String family,String q) throws IOException {
    Scan scan = new Scan();
    scan.addColumn(Bytes.toBytes(family),Bytes.toBytes(q));
    // 分页过滤器，只取一行数据
    Filter filter = new PageFilter(1);
    scan.setFilter(filter);

    ResultScanner scanner = table.getScanner(scan);
    for(Result result : scanner){
        byte[] value = result.getValue(Bytes.toBytes(family), Bytes.toBytes(q));
        System.out.println(Bytes.toString(value));
    }

}

testScanWithFilter("123456","info","name");

计数器

public static void testIncr(String rowKey, String family, String q) throws IOException {
    // 计数器，自增1
    tableIncr.incrementColumnValue(Bytes.toBytes(rowKey),
            Bytes.toBytes(family), Bytes.toBytes(q), 1);
    // 获取计数器当前值，不做自增
    long value = tableIncr.incrementColumnValue(Bytes.toBytes(rowKey),
            Bytes.toBytes(family), Bytes.toBytes(q), 0);
    System.out.println(value);
}

testIncr("did222", "camp", "501");