cassandra入门应用一

cassandra应用步骤：
1.在http://cassandra.apache.org/下载cassandra保存相应目录中
2.cassandra进行解压，
     a.解压命令：gunzip apache-cassandra-0.6.8-bin.tar.gz。
    b.对tar解压：tar -vxf apache-cassandra-0.6.8-bin.tar。
3.进入apache-cassandra-0.6.8目录bin下 运行 Cassandra
..............................
INFO 10:49:48,282 Starting up server gossip
INFO 10:49:48,327 Binding thrift service to localhost/127.0.0.1:9160
INFO 10:49:48,331 Cassandra starting up...
出现这个表示cassandra启动成功。
对cassandra简单讨论
1.cassandra是什么？
  是基于k-v的是一种高伸缩性，的第二代数据库，用来存储数据
  参考blog：
           http://www.iteye.com/topic/784054
          http://www.iteye.com/topic/722859


cassandra简单示例

  /**
 * 
 */
[color=green]package org.wolf.cassandra;

import org.apache.cassandra.thrift.Column;
import org.apache.cassandra.thrift.ColumnPath;
import org.apache.cassandra.thrift.ConsistencyLevel;
import org.apache.cassandra.thrift.InvalidRequestException;
import org.apache.cassandra.thrift.NotFoundException;
import org.apache.cassandra.thrift.TimedOutException;
import org.apache.cassandra.thrift.UnavailableException;
import org.apache.cassandra.thrift.Cassandra.Client;
import org.apache.thrift.TException;
import org.apache.thrift.protocol.TBinaryProtocol;
import org.apache.thrift.transport.TSocket;
import org.apache.thrift.transport.TTransport;
import org.apache.thrift.transport.TTransportException;

import com.sun.org.apache.bcel.internal.generic.NEW;

/**
 * cassandra 结构分为 server client
 * 
 * @author wolf * 
 */
public class CassandraDevelop {

	/**
	 *cassandra 客户端
	 */
	private Client cassClient;

	/**
	 * 连接协议,I/O layer,对 Java input/output streams 一个包装,其实现方式有 Tsocket，http等，
	 */
	private TTransport transport;

	private void initCassandra() throws TTransportException {
		String host = "localhost";
		int port = 9160;
		/* 指定服务器的地址和接口，以socket方式建立连接 */
		this.transport = new TSocket(host, port);
		/* 指定socket通讯协议为二进制流协议 */
		TBinaryProtocol binaryProtocol = new TBinaryProtocol(this.transport,
				false, false);
		this.cassClient = new Client(binaryProtocol);
		/* 建立通讯连接 */
		this.transport.open();

	}
	
	private void close(){
		this.transport.close();
	}

	/**
	 * 插入數字
	 * 
	 * @param tSpace
	 * @param tName
	 * @param rPara
	 * @param cName
	 * @param cValue
	 * @throws TException
	 * @throws TimedOutException
	 * @throws UnavailableException
	 * @throws InvalidRequestException
	 */
	private void insertData(String tSpace, String tName, String rPara,
			String cName) throws InvalidRequestException, UnavailableException,
			TimedOutException, TException {

		ColumnPath col = new ColumnPath(tName);
		col.setColumn(cName.getBytes());
		/**
		 * 执行插入操作，指定keysapce, row, col, 和数据内容， 后面两个参数一个是timestamp，
		 * 另外一个是consistency_level timestamp是用来做数据一致性保证的，
		 * 而consistency_level是用来控制数据分布的策略，前者的理论依据是bigtable, 后者的理论依据是dynamo
		 */
		this.cassClient.insert(tSpace, rPara, col,
				"using cassandra".getBytes(), System.currentTimeMillis(),
				ConsistencyLevel.ONE);
	}

	/**
	 * 获取列
	 * 
	 * @param tSpace
	 * @param tName
	 * @param rowParam
	 * @param colName
	 * @return
	 * @throws TException
	 * @throws TimedOutException
	 * @throws UnavailableException
	 * @throws NotFoundException
	 * @throws InvalidRequestException
	 */
	public Column getColumn(String tSpace, String tName, String rowParam,
			String colName) throws InvalidRequestException, NotFoundException,
			UnavailableException, TimedOutException, TException {
		ColumnPath col = new ColumnPath(tName);
		col.setColumn(colName.getBytes());
		/**
		 * 执行查询操作，指定keysapce, row, col， timestamp timestamp是用来做数据一致性保证的，
		 * 而consistency_level是用来控制数据分布的策略，前者的理论依据是bigtable, 后者的理论依据是dynamo
		 */
		return this.cassClient.get(tSpace, rowParam, col, ConsistencyLevel.ONE).column;
	}
	
	public static void main(String[] args) throws InvalidRequestException, UnavailableException, TimedOutException, TException, NotFoundException {
		CassandraDevelop cassandraDevelop = new CassandraDevelop();
		cassandraDevelop.initCassandra();
		String tSpace="Keyspace1";
		String row="employee";
		String tName="Standard2";
		cassandraDevelop.insertData(tSpace, tName, row, tName);
		
		Column column = cassandraDevelop.getColumn(tSpace, tName, row, "Standard2");
		System.out.println(new String(column.name));
		
	}
}[/color]