hbase学习，
主要基于Thrift进行了HBase接口的封装。接口中主要提供了get、getMultiple、getScannerResults、分批返回数据、put、putMultiple几个方法。
其中ByteBuffer table指HBase的表名；
TGet、TScan类似于HBase原生的Get、Scan；
key、svc是平台为每个应用分配的验证码和服务名，主要用于权限验证等。
1. get方法
根据TGet从表table中查询出来一条记录
public TResult get(ByteBuffer table, TGet get, ByteBuffer key, ByteBuffer svc)
样例代码：
ByteBuffer table = ByteBuffer.wrap("test_large".getBytes());
ByteBuffer key = ByteBuffer.wrap("key".getBytes());
ByteBuffer svc = ByteBuffer.wrap("svc".getBytes());
//打开链接
TTransport transport = new TSocket(host, port, timeout);
TProtocol protocol = new TBinaryProtocol(transport);
THBaseService.Iface client = new THBaseService.Client(protocol);
transport.open();
//设置TGet
TGet get = new TGet();
get.setRow("row_5000".getBytes());
//查询
TResult result = client.get(table, get, key, svc);
for (TColumnValue resultColumnValue : result.getColumnValues()) {
System.out.println("family = " + new String(resultColumnValue.getFamily()));
System.out.println("qualifier = " + new String(resultColumnValue.getFamily()));
System.out.println("value = " + new String(resultColumnValue.getValue()));
System.out.println("timestamp = " + resultColumnValue.getTimestamp());
}
transport.close();
2. getMultiple方法
根据List<TGet>从表table中查询出来多条记录
public List<TResult> getMultiple(ByteBuffer table, List<TGet> gets, ByteBuffer key, ByteBuffer svc)
样例代码：
TTransport transport = new TSocket(host, port, timeout);
TProtocol protocol = new TBinaryProtocol(transport);
THBaseService.Iface client = new THBaseService.Client(protocol);
transport.open();
//设置TGet
TGet get = new TGet();
get.setRow("row_5000".getBytes());
List<TGet> gets = new ArrayList<TGet>();
gets.add(get);
get = new TGet();
get.setRow("row2".getBytes());
gets.add(get);
//查询
List<TResult> results = client.getMultiple(table, gets, key, svc);
3. getScannerResults方法
根据TScan从表table中查询出来numRows条记录
public List<TResult> getScannerResults(ByteBuffer table, TScan scan, int numRows, ByteBuffer key, ByteBuffer svc)
样例代码：
TTransport transport = new TSocket(host, port, timeout);
TProtocol protocol = new TBinaryProtocol(transport);
THBaseService.Iface client = new THBaseService.Client(protocol);
transport.open();
//设置Tscan
TScan paramTScan = new TScan();
paramTScan.setCaching(1000);
paramTScan.setStartRow(Bytes.toBytes("row_0"));
//查询
int rowNum =10;
List<TResult> results = client.getScannerResults(table, paramTScan, rowNum, key, svc);
transport.close();
4. 分批返回数据的方法
//使用scan取得scannerId
public int openScanner(ByteBuffer table, TScan scan, ByteBuffer key, ByteBuffer svc)
//根据scannerId取得numRows条记录
public List<TResult> getScannerRows(int scannerId, int numRows)
//关闭Scanner
public void closeScanner(int scannerId)
样例代码：
TTransport transport = new TSocket(host, port, timeout);
TProtocol protocol = new TBinaryProtocol(transport);
THBaseService.Iface client = new THBaseService.Client(protocol);
transport.open();
//设置TScan
TScan paramTScan = new TScan();
paramTScan.setCaching(1000);
paramTScan.setStartRow(Bytes.toBytes("row_0"));
//取得scannerId
int scannerId = client.openScanner(table, paramTScan, key, svc);
List<TResult> results = null;
int rowNum = 1000;
while (true) {
//根据scannerId取得numRows条记录
results = client.getScannerRows(scannerId, rowNum);
if (results == null || results.size() == 0) {
break;
}
for (int i = 0; i < results.size(); i++) {
TResult result = results.get(i);
//TODO
}
}
client.closeScanner(scannerId);
transport.close();
5. TScan中的Filter设置
TScan中设置Filter时，只支持设置字符串格式。其中字符串格式和原生的HBase Shell中的格式相同。
样例代码：
TScan paramTScan = new TScan();
paramTScan.setCaching(1000);
paramTScan.setFilterString("PrefixFilter ('row5')".getBytes());
6. put方法
将put插入到表table中
publicvoid put(ByteBuffer table, TPut put, ByteBuffer key, ByteBuffer svc)
样例代码：
TTransport transport = new TSocket(host, port, timeout);
TProtocol protocol = new TBinaryProtocol(transport);
THBaseService.Iface client = new THBaseService.Client(protocol);
transport.open();
//拼装put
TPut put = new TPut();
//设置key
put.setRow("row3".getBytes());
//设置列
TColumnValue cell = new TColumnValue();
cell.setFamily("family1".getBytes());
cell.setQualifier("qualifier1".getBytes());
cell.setValue("value3".getBytes());
//组合多个列
List<TColumnValue> columnValues = new ArrayList<TColumnValue>();
columnValues.add(cell);
put.setColumnValues(columnValues);
//将put插入到example表中
client.put(ByteBuffer.wrap("example".getBytes()), put, key, svc);
transport.close();
7. putMultiple方法
将puts批量插入到表table中
publicvoid putMultiple(ByteBuffer table, List<TPut> puts, ByteBuffer key, ByteBuffer svc)
样例代码：
TTransport transport = new TSocket(host, port, timeout);
TProtocol protocol = new TBinaryProtocol(transport);
THBaseService.Iface client = new THBaseService.Client(protocol);
transport.open();
//拼装一个put
TPut put = new TPut();
put.setRow("row4".getBytes());
TColumnValue cell = new TColumnValue();
cell.setFamily("family1".getBytes());
cell.setQualifier("qualifier1".getBytes());
cell.setValue("value4".getBytes());
List<TColumnValue> columnValues = new ArrayList<TColumnValue>();
columnValues.add(cell);
put.setColumnValues(columnValues);
//将put加入到List<TPut>中
List<TPut> puts = new ArrayList<TPut>();
puts.add(put);
//拼装另一个put
put = new TPut();
put.setRow("row5".getBytes());
cell = new TColumnValue();
cell.setFamily("family1".getBytes());
cell.setQualifier("qualifier1".getBytes());
cell.setValue("value5".getBytes());
columnValues = new ArrayList<TColumnValue>();
columnValues.add(cell);
put.setColumnValues(columnValues);
//将put加入到List<TPut>中
puts.add(put);
//将List<TPut>批量插入到表example中
client.putMultiple(ByteBuffer.wrap("example".getBytes()), puts, key, svc);
transport.close();
8. 客户端连接池
建议客户端使用连接池来管理TSocket，这样可以提供效率，稳定性。平台提供了一个连接池供使用。
GenericConnectionProvider 线程安全的。初始化一次GenericConnectionProvider后，可以在多线程中使用genericConnectionProvider. getConnection()方法取得TSocket，TSocket使用完成后，调用GenericConnectionProvider. returnCon(TSocket)方法归还TSocket给连接池。
在进程结束或者tomcat关闭时，可以调用GenericConnectionProvider.destroy()方法，销毁连接池。
样例代码：
GenericConnectionProvider connectionProvider = new GenericConnectionProvider();
connectionProvider.setServiceIP(TestAiThriftClient.host);
connectionProvider.setServicePort(TestAiThriftClient.port);
connectionProvider.setConTimeOut(TestAiThriftClient.timeout);
connectionProvider.setMaxActive(20);
connectionProvider.setTestOnBorrow(true);
connectionProvider.setTestOnReturn(true);
connectionProvider.setTestWhileIdle(true);
//初始化连接池
connectionProvider.init();
//可以在多线程中，从连接池中取得连接
TSocket socket = connectionProvider.getConnection();
TProtocol protocol = new TBinaryProtocol(socket);
THBaseService.Iface client = new THBaseService.Client(protocol);
//执行查询逻辑
... ... ...
//查询完成后，归还连接给连接池。最好在try的finally块中执行该动作。
connectionProvider.returnCon(socket);
//进程停止或tomcat关闭时，须关闭连接池
connectionProvider.destroy();