zookeeper実現master-slave選挙(ZkClient実現)
15763 ワード
すべてのクライアントは1つのノードにmasterノードを登録し、登録に成功した場合のみmasterになります.
package master_slave;
import org.I0Itec.zkclient.IZkDataListener;
import org.I0Itec.zkclient.ZkClient;
import org.I0Itec.zkclient.exception.ZkNodeExistsException;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
public class MasterSelector {
private ZkClient zkClient;
private final static String MASTER_PATH = "/master";
private IZkDataListener dataListener;//
private UserCenter server;//
private UserCenter master;//master
private static boolean isRunning = false;
ScheduledExecutorService scheduledExecutorService = Executors.newScheduledThreadPool(1);
public MasterSelector(UserCenter server,ZkClient zkClient) {
System.out.println(server.toString());
this.server = server;
this.zkClient = zkClient;
this.dataListener = new IZkDataListener() {
@Override
public void handleDataChange(String s, Object o) throws Exception {
}
@Override
public void handleDataDeleted(String s) throws Exception {
// ，
chooseMaster();
}
};
}
public void start(){
//
if(!isRunning){
isRunning=true;
zkClient.subscribeDataChanges(MASTER_PATH,dataListener);
chooseMaster();
}
}
public void stop(){
//
if(isRunning){
scheduledExecutorService.shutdown();
zkClient.unsubscribeDataChanges(MASTER_PATH,dataListener);
releaseMaster();
}
}
//
private void chooseMaster(){
if (!isRunning) {
System.out.println(" 。");
return;
}
try {
zkClient.createEphemeral(MASTER_PATH,server);
master = server;
System.out.println(master.getMc_name());
// master
scheduledExecutorService.schedule(()->{
releaseMaster();
}, 5,TimeUnit.SECONDS);
}catch (ZkNodeExistsException e){
// master
UserCenter userCenter = zkClient.readData(MASTER_PATH);
if(userCenter==null) {
chooseMaster();// master
}else{
master=userCenter;
}
}
}
private void releaseMaster(){
//
// master
if(checkIsMaster()){
zkClient.delete(MASTER_PATH);
}
}
private boolean checkIsMaster(){
// master
UserCenter userCenter = zkClient.readData(MASTER_PATH);
if(userCenter.getMc_name().equals(server.getMc_name())){
master=server;
return true;
}
return false;
}
}