Hbase指定规则扫描表

1.创建一个scan扫描对象

2. scan对象中有setStartRow方法和setStopRow方法，分别指向开始扫描的rowkey和结束扫描的rowkey

3.scan对象中的addColumn方法指向所要查询的列簇中的某个列

要注意点是在指向同一列簇中的列时，要按照字典顺序指定，如果跳着指定则会出现NullPoinException(空指针异常)

public void Scan() throws IOException {
        HTableInterface student = connection.getTable("student");

        Scan scan = new Scan();
        //指定开始扫描的rowkey和结束扫描的rowkey
        scan.setStartRow("1500100018".getBytes());
        scan.setStopRow("1500100023".getBytes());
        //指定扫描指定列簇和列
        scan.addColumn("info".getBytes(),"name".getBytes());
        scan.addColumn("info".getBytes(),"age".getBytes());
        scan.addColumn("info".getBytes(),"gender".getBytes());
        //扫描表
        ResultScanner scanner = student.getScanner(scan);

        Result next;
        while ((next = scanner.next()) != null) {
            print(next);
        }
    }

    private void print(Result result) {
        String id = Bytes.toString(result.getRow());

        String name = Bytes.toString(result.getValue("info".getBytes(),"name".getBytes()));
        int age = Bytes.toInt(result.getValue("info".getBytes(),"age".getBytes()));
        String gender = Bytes.toString(result.getValue("info".getBytes(),"gender".getBytes()));
        String clazz = Bytes.toString(result.getValue("info".getBytes(),"clazz".getBytes()));

        System.out.println(id + "\t"+name + "\t"+age + "\t"+gender + "\t"+clazz);
    }