Sequoiadb测试体验系列之六–Java开发3

上一篇笔记中更新了在集合中的删除，更新，查询等操作。这次尝试一下SequoiaDB的集群操作。包括复制组的创建和删除，复制组的启动和停止，在复制组中添加、删除、启动、停止节点，获取复制组中的主从节点等。 import java.util.ArrayList;import java.util.L

上一篇笔记中更新了在集合中的删除，更新，查询等操作。这次尝试一下SequoiaDB的集群操作。包括复制组的创建和删除，复制组的启动和停止，在复制组中添加、删除、启动、停止节点，获取复制组中的主从节点等。

import java.util.ArrayList;import java.util.List;import org.bson.BSONObject;import org.bson.BasicBSONObject;import com.sequoiadb.base.Node.NodeStatus;import com.sequoiadb.base.DBCursor;import com.sequoiadb.base.Node;import com.sequoiadb.base.ReplicaGroup;import com.sequoiadb.base.Sequoiadb;import com.sequoiadb.exception.BaseException;public class BlogRG {	static String rgName = "testRG";	static String hostName = "sdbserver1";	public static void main(String[] args) {				//连接数据库		String host = "192.168.20.46";		String port = "11810";		String usr = "admin";		String password = "admin";		Sequoiadb sdb = null;		try {			sdb = new Sequoiadb(host + ":" + port, usr, password);		} catch (BaseException e) {			e.printStackTrace();			System.exit(1);		}				//打印有关复制组信息（名称、个数）		printGroupInfo(sdb);				//清除环境，删掉重复的复制组		if(isGroupExist(sdb,rgName)){			System.out.println("Removing the old replica group...");			sdb.removeReplicaGroup(rgName);		}				printGroupInfo(sdb);				//添加新复制组		System.out.println("Adding the new replica group...");		ReplicaGroup rg = sdb.createReplicaGroup(rgName);				printGroupInfo(sdb);				//打印复制组内节点信息		System.out.println("Tere are " + rg.getNodeNum(NodeStatus.SDB_NODE_ALL) + " nodes in the group.");				//添加三个新的节点		Node node1 = addNode(rg,50000);		Node node2 = addNode(rg,50010);		Node node3 = addNode(rg,50020);				//打印复制组内节点信息		System.out.println("Tere are " + rg.getNodeNum(NodeStatus.SDB_NODE_ALL) + " nodes in the group.");		//获取复制组的主从节点		Node master = rg.getMaster();		System.out.println("The master node is " +master.getPort());		System.out.println("The slave node is " + rg.getSlave().getPort());				//停止主节点		System.out.println("stoping the master node...");		master.stop();				//等待主节点停止		while(rg.getMaster().getPort() == master.getPort()){			try{				Thread.sleep(2000);			} catch (Exception e){			}		}		//查看新选举的主节点		System.out.println("re-selecting the master node...");		System.out.println("The master node is " + rg.getMaster().getPort());					}		private static void printGroupInfo(Sequoiadb sdb){		ArrayList names = sdb.getReplicaGroupNames();		int count = 0;		System.out.print("The replica groups are ");		for (Object name : names){			count++;			System.out.print((String)name + ", ");		}		System.out.println("\nThere are " + count + " replica groups in total.");	}		private static boolean isGroupExist(Sequoiadb sdb, String rgName){		ArrayList names = sdb.getReplicaGroupNames();		for (Object name : names){			if(rgName.equals((String)name))					return true;		}		return false;	}		private static Node addNode(ReplicaGroup rg, int port){		if(rg.getNode(hostName,port)!= null)			rg.removeNode(hostName, port, null);		Node node = rg.createNode(hostName,port,"/opt/sequoiadb/database/test/" + port,null);		System.out.println("starting the node " + port + "...");		node.start();		return node;	}}

上面的代码在数据库中添加新的复制组，并在新的复制组内添加三个主节点，数据组自动选举出新的主节点，停止主节点后，复制组内重新选举新的主节点。

运行以上代码后的结果是：

The replica groups are SYSCatalogGroup, datagroup, testRG, There are 3 replica groups in total.Removing the old replica group...The replica groups are SYSCatalogGroup, datagroup, There are 2 replica groups in total.Adding the new replica group...The replica groups are SYSCatalogGroup, datagroup, testRG, There are 3 replica groups in total.Tere are 0 nodes in the group.starting the node 50000...starting the node 50010...starting the node 50020...Tere are 3 nodes in the group.The master node is 50000The slave node is 50010stoping the master node...re-selecting the master node...The master node is 50020

可以看出，程序开始运行时，数据库内有三个复制组，其中testRG是上次运行遗留下来的无用复制组，另外两个是数据库默认的两个复制组。通过removeReplicaGroup()方法删除多余的testRG复制组，之后通过createReplicaGroup()添加新的testRG复制组，并且在新建的组内通过createNode()和start()添加并启动50000,50010,50020三个新的节点。通过getMaster()和getSlave()方法获取组内的主从节点，并利用stop()停止主节点50000，主节点完全停止后，组内将重新自动选举出新的主节点50020。

运行完成后，通过shell控制台查看数据库testRG复制组的详细情况：

>rg.getDetail(){  "Group": [    {      "HostName": "sdbserver1",      "dbpath": "/opt/sequoiadb/database/test/50000",      "Service": [        {          "Type": 0,          "Name": "50000"        },        {          "Type": 1,          "Name": "50001"        },        {          "Type": 2,          "Name": "50002"        }      ],      "NodeID": 1053    },    {      "HostName": "sdbserver1",      "dbpath": "/opt/sequoiadb/database/test/50010",      "Service": [        {          "Type": 0,          "Name": "50010"        },        {          "Type": 1,          "Name": "50011"        },       <em style="color:transparent">本文来源gao.dai.ma.com搞@代*码#网</em> {          "Type": 2,          "Name": "50012"        }      ],      "NodeID": 1054    },    {      "HostName": "sdbserver1",      "dbpath": "/opt/sequoiadb/database/test/50020",      "Service": [        {          "Type": 0,          "Name": "50020"        },        {          "Type": 1,          "Name": "50021"        },        {          "Type": 2,          "Name": "50022"        }      ],      "NodeID": 1055    }  ],  "GroupID": 1023,  "GroupName": "testRG",  "PrimaryNode": 1055,  "Role": 0,  "Status": 0,  "Version": 4,  "_id": {    "$oid": "53d9d38e14a63a88c621edd8"  }}Return 1 row(s).Takes 0.4716s.

可以看出组内有三个节点，主节点（PrimaryNode）为1055，也就是50020。

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