zookeeper学习【1】配置管理

为什么要用统一配置？

我们做项目时用到的配置比如数据库配置等...我们都是写死在项目里面，如果需要更改，那么也是的修改配置文件然后再投产上去，那么问题来了，如果做集群的呢，有100台机器，这时候做修改那就太不切实际了；那么就需要用到统一配置管理啦。

采用方案

1.公共配置抽取存放于zookeeper中并落地数据库

2.对公共配置修改后发布到zookeeper中并落地数据库

3.对应用开启配置实时监听，zookeeper配置文件一旦被修改，应用可实时监听到并获取

实现代码：

import java.io.Serializable;

public class Config implements Serializable{

    /**
     *
     */
    private static final long serialVersionUID = 1L;
    private String userNm;
    private String userPw;

    public Config() {
    }
    public Config(String userNm, String userPw) {
        this.userNm = userNm;
        this.userPw = userPw;
    }
    public String getUserNm() {
        return userNm;
    }
    public void setUserNm(String userNm) {
        this.userNm = userNm;
    }
    public String getUserPw() {
        return userPw;
    }
    public void setUserPw(String userPw) {
        this.userPw = userPw;
    }
    @Override
    public String toString() {
        return "Config [userNm=" + userNm + ", userPw=" + userPw + "]";
    }

}

import org.I0Itec.zkclient.ZkClient;

public class ZkConfigMag {

    private Config config;
    /**
     * 从数据库加载配置
     */
    public Config downLoadConfigFromDB(){
        //getDB
        config = new Config("nm", "pw");
        return config;
    }

    /**
     * 配置文件上传到数据库
     */
    public void upLoadConfigToDB(String nm, String pw){
        if(config==null)config = new Config();
        config.setUserNm(nm);
        config.setUserPw(pw);
        //updateDB
    }

    /**
     * 配置文件同步到zookeeper
     */
    public void syncConfigToZk(){
        ZkClient zk = new ZkClient("localhost:2181");
        if(!zk.exists("/zkConfig")){
            zk.createPersistent("/zkConfig",true);
        }
        zk.writeData("/zkConfig", config);
        zk.close();
    }
}

public class ZkConfigTest {

    public static void main(String[] args) {
        ZkConfigMag mag = new ZkConfigMag();
        Config config = mag.downLoadConfigFromDB();
        System.out.println("....加载数据库配置...."+config.toString());
        mag.syncConfigToZk();
        System.out.println("....同步配置文件到zookeeper....");

        //歇会，这样看比较清晰
        try {
            Thread.sleep(10000);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        mag.upLoadConfigToDB("ccccc", "ppppp");
        System.out.println("....修改配置文件...."+config.toString());
        mag.syncConfigToZk();
        System.out.println("....同步配置文件到zookeeper....");


    }

}

import org.I0Itec.zkclient.IZkDataListener;
import org.I0Itec.zkclient.ZkClient;

public class ZkGetConfigClient {

    private Config config;

    public Config getConfig() {
        ZkClient zk = new ZkClient("localhost:2181");
        config = (Config)zk.readData("/zkConfig");
        System.out.println("加载到配置："+config.toString());

        //监听配置文件修改
        zk.subscribeDataChanges("/zkConfig", new IZkDataListener(){
            @Override
            public void handleDataChange(String arg0, Object arg1)
                    throws Exception {
                config = (Config) arg1;
                System.out.println("监听到配置文件被修改："+config.toString());
            }

            @Override
            public void handleDataDeleted(String arg0) throws Exception {
                config = null;
                System.out.println("监听到配置文件被删除");
            }

        });
        return config;
    }
    public static void main(String[] args) {
        ZkGetConfigClient client = new ZkGetConfigClient();
        client.getConfig();
        System.out.println(client.config.toString());
        for(int i = 0;i<100;i++){
            System.out.println(client.config.toString());
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

    }


}