一、预分区

1 原因：
热点问题：数据持续读写一个region（或节点）上。
region自动分区会造成频繁IO。

2 设置分区
（前缀）范围

-10,10-20,20-30,30-40,40-50,50-60,60-70,70-80,80-90,90-

生成分区前缀：

private byte[][] getSplitKeys() {
		String[] keys = new String[] { "00_", "10_", "20_", "30_", "40_", "50_", "60_", "70_", "80_", "90_" };
		byte[][] splitKeys = new byte[keys.length][];
		TreeSet<byte[]> rows = new TreeSet<byte[]>(Bytes.BYTES_COMPARATOR);// 升序排序
		for (int i = 0; i < keys.length; i++) {
			rows.add(Bytes.toBytes(keys[i]));
		}
		Iterator<byte[]> rowKeyIter = rows.iterator();
		int i = 0;
		while (rowKeyIter.hasNext()) {
			byte[] tempRow = rowKeyIter.next();
			rowKeyIter.remove();
			splitKeys[i] = tempRow;
			i++;
		}
		return splitKeys;
	}

建表：

public boolean createTableBySplitKeys(String tableName, List<String> columnFamily) {
		try {
			if (StringUtils.isBlank(tableName) || columnFamily == null || columnFamily.size() < 0) {
				log.error("tableName|columnFamily不为null");
			}
			Admin admin = connection.getAdmin();
			TableName tableName1 = TableName.valueOf(tableName);
			if (admin.tableExists(tableName1)) {
				return true;
			} else {
				TableDescriptorBuilder builder = TableDescriptorBuilder.newBuilder(tableName1);
				for (String cf : columnFamily) {
					builder.setColumnFamily(ColumnFamilyDescriptorBuilder.newBuilder(Bytes.toBytes(cf)).build());
				}
				byte[][] splitKeys = getSplitKeys();
				admin.createTable(builder.build(), splitKeys);// 指定splitkeys
				log.info("表" + tableName + "创建成功，列族：" + columnFamily.toString());
			}
		} catch (Exception e) {
			e.printStackTrace();
			return false;
		}
		return true;
	}

造数据：

	private String getRandomNumber() {
		String ranStr = Math.random() + "";
		int pointIndex = ranStr.indexOf(".");
		return ranStr.substring(pointIndex + 1, pointIndex + 3);
	}

	private List<Put> batchPut() {
		List<Put> list = new ArrayList<Put>();
		for (int i = 1; i <= 10000; i++) {
			byte[] rowkey = Bytes.toBytes(getRandomNumber() + "-" + System.currentTimeMillis() + "-" + i);
			Put put = new Put(rowkey);
			put.addColumn(Bytes.toBytes("info"), Bytes.toBytes("name"), Bytes.toBytes("zs" + i));
			list.add(put);
		}
		return list;
	}

查看web ui以验证：http://localhost:16010/table.jsp?name=test
代码地址：https://github.com/xing54321/hbase_demo