Spring MVC Zookeeper 统一配置管理

资料摘自：http://www.big-mouth.cn/blog/65.html

 

背景说明：在基于Spring MVC框架的开发的项目中，由于存在大量的数据库配置、第三方配置信息、环境路径配置信息，一直使用Maven的profile方式来对各种配置信息进行管理(该方式不多做介绍)，在维护方面成本较高。针对以上情况，准备借助zookeeper来对不同配置信息进行统一管理(当然其他缓存工具也可以，原理相同)。

 

第一步：安装zookeeper服务端(资料较多，这里不多解释)

 

第二步：在java中引入apache.zookeeper.ZooKeeper第三方API。

 

<dependency>
	<groupId>org.apache.zookeeper</groupId>
	<artifactId>zookeeper</artifactId>
	<version>3.4.6</version>
</dependency>

 

 

第三步：编写zookeeper工具类(简单工具类)

 

package cn.com.timerbin.zookeeper.demo;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.List;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.ZooKeeper;

public class ZookeeperClientUtil {
	private ZooKeeper zk;
	//zookeeper地址
	private String servers;
	//链接超时时间
	private int sessionTimeout = 40000;
	
	private String mainPath;
	
	public ZooKeeper getAliveZk() {
		ZooKeeper aliveZk = zk;
		if (aliveZk != null && aliveZk.getState().isAlive()) {
			return aliveZk;
		} else {
			zkReconnect();
			return zk;
		}
	}
	public synchronized void zkReconnect() {
		close();
		try {
			connect();
		} catch (IOException e) {
		}
	}
	public synchronized void close() {
		if (zk != null) {
			try {
				zk.close();
			} catch (InterruptedException e) {
			}
			zk = null;
		}
	}
	private synchronized void connect() throws IOException {
		if (zk == null  && !StringUtils.isBlank(servers))
			zk = new ZooKeeper(servers, sessionTimeout, null);
	}
	public String getData(String path) {
		String result = null;
		try {
			byte [] data = getAliveZk().getData(path, Boolean.TRUE,null);
			if(null != data){
				result = new String(data, "UTF-8");
			}
		} catch (KeeperException e) {
		} catch (InterruptedException e) {
		} catch (UnsupportedEncodingException e) {
		}
		return result ;
	}
	public List<String> getChildren(){
		List<String> data = null;
		try {
			data = getAliveZk().getChildren(mainPath, Boolean.TRUE);
		} catch (KeeperException e) {
		} catch (InterruptedException e) {
		}
		return data;
	}
	public void setSessionTimeout(int sessionTimeout) {
		this.sessionTimeout = sessionTimeout;
	}
	public String getMainPath() {
		return mainPath;
	}
	public void setMainPath(String mainPath) {
		this.mainPath = mainPath;
	}
	public void setServers(String servers) {
		this.servers = servers;
	}
}

注：此工具类仅供参考，请注意其中 zk.getChildren()/zk.getData()方法中的Watcher参数使用。

 

 

第四步：Spring配置文件中对ZookeeperClientUtil 配置定义

 

<bean id="zookeeperClient" class="cn.com.timerbin.zookeeper.demo.ZookeeperClientUtil">
           <property name="servers" value="127.0.0.1:2181" />
           <property name="mainPath" value="/configuration/allconfig" />
 </bean>

 

 

 

第五步：重写配置文件配置器

 

package cn.com.timerbin.zookeeper.demo;
import java.util.List;
import java.util.Properties;
import org.springframework.beans.BeansException;
import org.springframework.beans.PropertyValue;
import org.springframework.beans.factory.BeanInitializationException;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.config.PropertyOverrideConfigurer;
import org.springframework.beans.factory.config.PropertyPlaceholderConfigurer;
import cn.com.timerbin.zookeeper.demo.ZookeeperClientUtil;
public class ZooKeeperPropertyPlaceholderConfigurer extends PropertyPlaceholderConfigurer {
	
	private ZookeeperClientUtil configurationClient;

	public void setConfigurationClient(ZookeeperClientUtil configurationClient) {
		this.configurationClient = configurationClient;
	}

	@Override
    protected void processProperties(ConfigurableListableBeanFactory beanFactoryToProcess, Properties props)
            throws BeansException {
        try {
        	List<String> list= configurationClient.getChildren();
        	for(String key:list){
        		String value = configurationClient.getData(configurationClient.getMainPath()+"/"+key);
        		if(!StringUtils.isBlank(value)){
        			props.put(key,value);
        		}
        	}
        } catch (Exception e) {
        }
        super.processProperties(beanFactoryToProcess, props);
        
    }
}

 

 

第六步：在Spring配置文件中对ZooKeeperPropertyPlaceholderConfigurer进行配置定义

 

<bean id="zooKeeperPropertyPlaceholderConfigurer" class="cn.com.timerbin.zookeeper.demo.ZooKeeperPropertyPlaceholderConfigurer">
	<property name="configurationClient" ref="zookeeperClient"></property>
	<property name="order" value="1" />
	<property name="ignoreUnresolvablePlaceholders" value="true" />
</bean>

 其中：ignoreUnresolvablePlaceholders:配置即当此PropertyPlaceholder不可解析时是否忽略。

 

注：如果在第六步中配置中配置了如下信息时

<property name="locations">
	<list>
		<value>classpath:application.properties</value>
	</list>
</property>

 此时在第五部中的processProperties方法的props中就已经包含了application.properties配置中的所有配置信息，关于工具类（ZookeeperClientUtil）中的一些配置参数的设置也可以考虑基于props来进行定义设置！