Zookeeper注冊中心概述

Zookeeper介紹(配合Dubbox使用)

　　官方推薦使用zookeeoer注冊中心,注冊中心負責服務地址的注冊和查找,相當於目錄服務,提供提供者和消費者只在啟動時與注冊中心交互,注冊中心不轉發請求,壓力小.

　　zookeeper是Apacahe Hadoop的子項目,是一個樹形的目錄服務,支持變更推送,適合作為Dubbox服務的注冊中心,工業強度較高,可用於生產環境.

　　Zookeeper在Linux系統的安裝

安裝步驟:

第一步:安裝Jdk

第二步:把zookeeper的壓縮包上傳到linux系統.

第三步:解壓縮壓縮包

tar -zxvf zookeeper-3.4.6.tar.gz

第四步:進入conf目錄,吧zoo sample.cfg改名為zoo.cfg

Zookeeper服務啟動

進入bin目錄,啟動服務輸入命令

 ./zkServer.sh start

輸出一下內容表示啟動成功

關閉服務輸入命令

./zkServer.sh stop

查看狀態:

./zkServer.sh status

如果啟動狀態,提示:

如果未啟動狀態,提示:

如果想要配置離線約束:

這個地址:http://code.alibabatech.com/schema/dubbo/dubbo.xsd

不配置也是可以的.

入門的一個小Demo

配置Maven環境

-DarchetypeCatalog=internal

服務提供者開發:

開發步驟:

（1）創建Maven工程（WAR）dubboxdemo-service,  war項目  ，在pom.xml中引入依賴

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>cn.itcast.dubboxdemo</groupId>
  <artifactId>dubboxdemo-service</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>  
   <properties>        
        <spring.version>4.2.4.RELEASE</spring.version>
   </properties>    
    <dependencies>
        <!-- Spring -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jms</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context-support</artifactId>
            <version>${spring.version}</version>
        </dependency>    
        <!-- dubbo相關 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>dubbo</artifactId>
            <version>2.8.4</version>            
        </dependency>
        <dependency>
            <groupId>org.apache.zookeeper</groupId>
            <artifactId>zookeeper</artifactId>
            <version>3.4.6</version>
        </dependency>
        <dependency>
            <groupId>com.github.sgroschupf</groupId>
            <artifactId>zkclient</artifactId>
            <version>0.1</version>
        </dependency>        
        <dependency>
            <groupId>javassist</groupId>
            <artifactId>javassist</artifactId>
            <version>3.11.0.GA</version>
        </dependency>    
<dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>fastjson</artifactId>
      <version>1.2.28</version>
    </dependency>    
    </dependencies>
   <build>  
      <plugins>
          <plugin>  
              <groupId>org.apache.maven.plugins</groupId>  
              <artifactId>maven-compiler-plugin</artifactId>  
              <version>2.3.2</version>  
              <configuration>  
                  <source>1.7</source>  
                  <target>1.7</target>  
              </configuration>  
          </plugin>  
          <plugin>
                <groupId>org.apache.tomcat.maven</groupId>
                <artifactId>tomcat7-maven-plugin</artifactId>
                <configuration>
                    <!-- 指定端口 -->
                    <port>8081</port>
                    <!-- 請求路徑 -->
                    <path>/</path>
                </configuration>
            </plugin>
      </plugins>  
    </build>
</project>

（2）在工程的webapps下創建WEB-INF文件夾，創建web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    version="2.5">    
    <!-- 加載spring容器 -->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:applicationContext*.xml</param-value>
    </context-param>
    <listener>        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>    
</web-app>

（3）創建業務接口

創建包cn.itcast.dubbodemo.service，用於存放業務接口，創建接口

package cn.itcast.dubbodemo.service;
/**
 * 業務接口
 * @author Administrator
 *
 */
public interface UserService {    
    public String getName();    
}

（4）創建業務實現類

創建包cn.itcast.dubbodemo.service.impl ，用於存放業務實現類。創建業務實現類：

package cn.itcast.dubbodemo.service.impl;
import com.alibaba.dubbo.config.annotation.Service;
import cn.itcast.dubbodemo.service.UserService;
@Service
public class UserServiceImpl implements UserService {
    public String getName() {        
        return "itcast";
    }
}

注意：Service注解與原來不同，需要引入com.alibaba包下的

（5）編寫配置文件

在src/main/resources下創建applicationContext-service.xml ,內容如下：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:dubbo="http://code.alibabatech.com/schema/dubbo" xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
        http://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
     
    <dubbo:application name="dubboxdemo-service"/>  
<dubbo:registry address="zookeeper://192.168.200.128:2181"/> 
<dubbo:annotation package="cn.itcast.dubboxdemo.service" /> 
</beans>

注意：dubbo:annotation用於掃描@Service注解。

3.5.2服務消費者開發

開發步驟：

（1）創建Maven工程（WAR）dubboxdemo-web, war項目，在pom.xml引入依賴，同“dubboxdemo-service”工程。區別就是把tomcat插件的運行端口改為8082 。

（2）在webapps目錄下創建WEB-INF 目錄，並創建web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    version="2.5">    
   <!-- 解決post亂碼 -->
    <filter>
        <filter-name>CharacterEncodingFilter</filter-name>        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>utf-8</param-value>
        </init-param>
        <init-param>  
            <param-name>forceEncoding</param-name>  
            <param-value>true</param-value>  
        </init-param>  
    </filter>
    <filter-mapping>
        <filter-name>CharacterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>        
  <servlet>
      <servlet-name>springmvc</servlet-name>      <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
      <!-- 指定加載的配置文件 ，通過參數contextConfigLocation加載-->
      <init-param>
          <param-name>contextConfigLocation</param-name>
          <param-value>classpath:applicationContext-web.xml</param-value>
      </init-param>
  </servlet>  
  <servlet-mapping>
      <servlet-name>springmvc</servlet-name>
      <url-pattern>*.do</url-pattern>
  </servlet-mapping>
</web-app>

（3）拷貝業務接口

 

將“dubboxdemo-service”工程的cn.itcast.dubboxdemo.service 包以及下面的接口拷貝至此工程。

 （4）編寫Controller

 

package cn.itcast.dubboxdemo.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import cn.itcast.dubbodemo.service.UserService;
@Controller
@RequestMapping("/user")
public class UserController {
    @Reference
    private UserService userService;    
    @RequestMapping("/showName")
    @ResponseBody
    public String showName(){
        return userService.getName();
    }        
}

（5）編寫spring配置文件

在src/main/resources下創建applicationContext-web.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:dubbo="http://code.alibabatech.com/schema/dubbo" xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
        http://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <mvc:annotation-driven>
      <mvc:message-converters register-defaults="true">
        <bean class="com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter">  
          <property name="supportedMediaTypes" value="application/json"/>
          <property name="features">
            <array>
              <value>WriteMapNullValue</value>
              <value>WriteDateUseDateFormat</value>
            </array>
          </property>
        </bean>
      </mvc:message-converters>  
    </mvc:annotation-driven>
    <!-- 引用dubbo 服務 -->
    <dubbo:application name="dubboxdemo-web" />
    <dubbo:registry address="zookeeper://192.168.200.128:2181"/>
     <dubbo:annotation package="cn.itcast.dubboxdemo.controller" />
</beans>

測試:

啟動服務消費方和服務提供方,兩個tomcat,以內使用了插件,所以直接啟動就好.

tomcat7:run

 

在瀏覽器輸入http://localhost:8082/user/showName.do，查看瀏覽器輸出結果

package cn.itcast.dubbodemo.service.impl;

import com.alibaba.dubbo.config.annotation.Service;

import cn.itcast.dubbodemo.service.UserService;

@Service

publicclass UserServiceImpl implements UserService {

    public String getName() {      

        return"itcast";

    }

}