业务需要统计每天hbase的数据量，而且每天增量有上百万条。

网上找了些代码，很多推荐使用Coprocessor的方式，执行效率高。但在我的大数据环境 运行出错，报“No registered coprocessor service found for name AggregateService in region xxx”。后来发现是第一次运行时需要下面这些代码来修改配置

 String coprocessorClass = "org.apache.hadoop.hbase.coprocessor.AggregateImplementation";
        if (! descriptor.hasCoprocessor(coprocessorClass)) {
            descriptor.addCoprocessor(coprocessorClass);
        }
        admin.modifyTable(name, descriptor);
        admin.enableTable(name);

public void rowCount(String tablename){
    try {
        //提前创建connection和conf
        Admin admin = connection.getAdmin();
        TableName name=TableName.valueOf(tablename);
        //先disable表，添加协处理器后再enable表
        admin.disableTable(name);
        HTableDescriptor descriptor = admin.getTableDescriptor(name);
        String coprocessorClass = "org.apache.hadoop.hbase.coprocessor.AggregateImplementation";
        if (! descriptor.hasCoprocessor(coprocessorClass)) {
            descriptor.addCoprocessor(coprocessorClass);
        }
        admin.modifyTable(name, descriptor);
        admin.enableTable(name);

        //计时
        StopWatch stopWatch = new StopWatch();
        stopWatch.start();

        Scan scan = new Scan();
        AggregationClient aggregationClient = new AggregationClient(conf);

        System.out.println("RowCount: " + aggregationClient.rowCount(name, new LongColumnInterpreter(), scan));
        stopWatch.stop();
        System.out.println("统计耗时：" +stopWatch.getTotalTimeMillis());
    } catch (Throwable e) {
        e.printStackTrace();
    }
}

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