这篇文章将为大家详细讲解有关ZooKeeper如何配置管理，小编觉得挺实用的，因此分享给大家做个参考，希望大家阅读完这篇文章后可以有所收获。
主要完成的目标是：Spring PropertyPlaceholderConfigurer配置文件加载器集成ZooKeeper来实现远程配置读取。
配置管理（Configuration Management）。
在集群服务中，可能都会遇到一个问题：那就是当需要修改配置的时候，必须要对每个实例都进行修改，这是一个很繁琐的事情，并且易出错。当然可以使用脚本来解决，但这不是最好的解决办法。
OK，Let's go！
我们先看看项目结构
ZooKeeperPropertyPlaceholderConfigurer.java
继承org.springframework.beans.factory.config.PropertyPlaceholderConfigurer，重写processProperties(beanFactoryToProcess, props)来完成远端配置加载的实现
package org.bigmouth.common.zookeeper.config.spring;
import java.io.UnsupportedEncodingException;
import java.util.Properties;
import org.apache.commons.lang.StringUtils;
import org.bigmouth.common.zookeeper.config.Config;
import org.bigmouth.common.zookeeper.config.ZooKeeperConfig;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.config.PropertyPlaceholderConfigurer;
public class ZooKeeperPropertyPlaceholderConfigurer extends PropertyPlaceholderConfigurer {
public static final String PATH = "zoo.paths";
@Override
protected void processProperties(ConfigurableListableBeanFactory beanFactoryToProcess, Properties props)
throws BeansException {
super.processProperties(beanFactoryToProcess, props);
try {
fillCustomProperties(props);
System.out.println(props);
}
catch (Exception e) {
// Ignore
e.printStackTrace();
}
}
private void fillCustomProperties(Properties props) throws Exception {
byte[] data = getData(props);
fillProperties(props, data);
}
private void fillProperties(Properties props, byte[] data) throws UnsupportedEncodingException {
String cfg = new String(data, "UTF-8");
if (StringUtils.isNotBlank(cfg)) {
// 完整的应该还需要处理：多条配置、value中包含=、忽略#号开头
String[] cfgItem = StringUtils.split(cfg, "=");
props.put(cfgItem[0], cfgItem[1]);
}
}
private byte[] getData(Properties props) throws Exception {
String path = props.getProperty(PATH);
Config config = new ZooKeeperConfig();
return config.getConfig(path);
}
}
Config.java
配置操作接口
package org.bigmouth.common.zookeeper.config;
public interface Config {
byte[] getConfig(String path) throws Exception;
}
Startup.java
程序启动入口
package org.bigmouth.common.zookeeper.config;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Startup {
public static void main(String[] args) {
new ClassPathXmlApplicationContext("classpath:/config/applicationContext.xml");
}
}
ZooKeeperConfig.java
配置操作接口ZooKeeper的实现
package org.bigmouth.common.zookeeper.config;
import org.apache.curator.framework.CuratorFramework;
import org.apache.zookeeper.data.Stat;
public class ZooKeeperConfig implements Config {
@Override
public byte[] getConfig(String path) throws Exception {
CuratorFramework client = ZooKeeperFactory.get();
if (!exists(client, path)) {
throw new RuntimeException("Path " + path + " does not exists.");
}
return client.getData().forPath(path);
}
private boolean exists(CuratorFramework client, String path) throws Exception {
Stat stat = client.checkExists().forPath(path);
return !(stat == null);
}
}
ZooKeeperFactory.java
管理ZooKeeper客户端连接
package org.bigmouth.common.zookeeper.config;
import org.apache.curator.RetryPolicy;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.retry.ExponentialBackoffRetry;
public class ZooKeeperFactory {
public static final String CONNECT_STRING = "172.16.3.42:2181,172.16.3.65:2181,172.16.3.24:2181";
public static final int MAX_RETRIES = 3;
public static final int BASE_SLEEP_TIMEMS = 3000;
public static final String NAME_SPACE = "cfg";
public static CuratorFramework get() {
RetryPolicy retryPolicy = new ExponentialBackoffRetry(BASE_SLEEP_TIMEMS, MAX_RETRIES);
CuratorFramework client = CuratorFrameworkFactory.builder()
.connectString(CONNECT_STRING)
.retryPolicy(retryPolicy)
.namespace(NAME_SPACE)
.build();
client.start();
return client;
}
}
applicationContext.xml
配置加载器使用我们自己创建的ZooKeeperPropertyPlaceholderConfigurer，因为它重写了processProperties方法。这个方法里会去读取远程配置。
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
<bean class="org.bigmouth.common.zookeeper.config.spring.ZooKeeperPropertyPlaceholderConfigurer">
<property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE" />
<property name="ignoreResourceNotFound" value="true" />
<property name="locations">
<list>
<value>classpath:application.properties</value>
</list>
</property>
</bean>
</beans>
application.properties
项目配置文件，里面除了配置ZooKeeper服务器地址和读取的节点以外，其他所有的配置都应该保存在ZooKeeper中。
zoo.paths=/properties
设置ZooKeeper数据
登录ZooKeeper中为节点 /cfg/properties 添加一条配置项：
如图所示：我创建了一个节点 /cfg/properties 并设置内容为：jdbc.driver=org.postgresql.Driver
运行Startup.java
OK 了，zoo.paths是本地application.properties文件中的，jdbc.driver是远程ZooKeeper服务器中的。
项目中需要依赖的jar包
<dependency>
<groupId>commons-lang</groupId>
<artifactId>commons-lang</artifactId>
<version>2.4</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>3.0.3.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>3.0.3.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>3.0.3.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context-support</artifactId>
<version>3.0.3.RELEASE</version>
</dependency>
<!-- ZooKeeper -->
<dependency>
<groupId>org.apache.zookeeper</groupId>
<artifactId>zookeeper</artifactId>
<version>3.4.6</version>
</dependency>
<dependency>
<groupId>org.apache.curator</groupId>
<artifactId>curator-framework</artifactId>
<version>2.4.2</version>
</dependency>
<dependency>
<groupId>org.apache.curator</groupId>
<artifactId>curator-recipes</artifactId>
<version>2.4.2</version>
</dependency>
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