08. Zookeeper JavaAPI-环境搭建-蒲公英云

08. Zookeeper JavaAPI-环境搭建

Zookeeper 提供了Java 访问的API, 但是笔者API 并不是太友好, 使用起来并不方便. 笔者认为, 倘若在生产环境下需要直接操作Zookeeper, 那么笔者建议对常用API 做二次封装.

1. Java 开发环境搭建

新建一maven 项目, 引入依赖

1.1 pom 依赖

引入zookeeper 核心依赖, 顺便引入单元测试和日志依赖.

<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
    </dependency>
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>1.2.17</version>
    </dependency>
    <dependency>
        <groupId>org.apache.zookeeper</groupId>
        <artifactId>zookeeper</artifactId>
        <version>3.4.6</version>
    </dependency>
</dependencies>

1.2 日志输出

Zookeeper 默认采用log4j 输出日志, 因此在类加载路径下添加log4j.properties 配置文件

log4j.rootLogger=INFO, stdout  
log4j.appender.stdout=org.apache.log4j.ConsoleAppender  
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout  
log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n  
log4j.appender.logfile=org.apache.log4j.FileAppender  
log4j.appender.logfile.File=target/spring.log  
log4j.appender.logfile.layout=org.apache.log4j.PatternLayout  
log4j.appender.logfile.layout.ConversionPattern=%d %p [%c] - %m%n

2. 创建Zookeeper 连接

Java 对Zookeeper 的操作全部封装在Zookeeper 对象中, 需要先创建Zookeeper对象, 与Zookeeper服务建立连接. 获取到Zookeeper 连接对象之后, 就可以对zNode 进行操作了.

public class TestAPI { 
    // zookeeper 地址, 多个地址以逗号割开
    private static String zkServer = "127.0.0.1:2181,127.0.0.1:2182,127.0.0.1:2183";
    // 会话超时时间
    private static int sessionTimeout = 3000;
    // zookeeper 客户端连接
    private static ZooKeeper zooKeeper;
    @Test
    public void init() throws Exception{ 
        zooKeeper = new ZooKeeper(zkServer, sessionTimeout, watchedEvent ->{ });
        System.out.println("******************* init start ***********************");
        System.out.println("state:" + zooKeeper.getState());
        System.out.println("sessionPwd:" + zooKeeper.getSessionPasswd());
        System.out.println("sessionId:" + zooKeeper.getSessionId());
        System.out.println("timeout:" + zooKeeper.getSessionTimeout());
        System.out.println("******************* init end ***********************");
    }
}