JavaEE學習日誌(一百一十一): 分佈式項目基本構建（Dubbo和Zookeeper）

SOA架構

Tomcat極限: 單臺Tomcat極限基本是可以同時抗住500個併發.

傳統行業項目: 併發低, 數據量小, 不需要高可用, 例如: oa, erp, crm項目, 或者政府項目, 銀行項目等.
互聯網項目: 高併發, 大數據量, 高可用 例如: 京東, 百度, 淘寶, 天貓, 餓了麼, 美團, 滴滴, ofo, 釘釘

soa架構也叫分佈式架構，由互聯網項目使用

Dubbo

dubbo作用
跨項目調用方法, 例如從A項目中的controller調用B項目中的service方法

dubbo同類型的技術都有哪些
rpc協議實現框架: dubbo, dubbox, springCloud

• 優點: 傳輸效率快
• 缺點: controller和service兩個項目必須都是Java語言實現

webService技術: 代表框架有cxf
底層使用的協議叫做soap協議, 其實傳輸的就是xml數據

• 優點: 可以跨語言跨平臺, controller可以是Java語言實現, service可以是.net或者C語言等語言實現
• 缺點: 傳輸效率低

dubbo用法

• service實現類上寫@Service註解, 注意這個@Service註解不是spring包的是阿里的dubbo包下的
• controller注入的時候使用@Refrence註解來進行注入, 也是阿里dubbo包下面的.
• 如果controller和service之間傳輸pojo實體類, 那麼實體類必須實現Java的序列化接口

dubbo調用流程

Zookeeper

在linux下安裝zookeeper

安裝完成

將目錄改成zookeeper

查看zoo.cfg配置文件


啓動zookeeper

zookeeper命令:
啓動: ./zkServer.sh start
關閉: ./zkServer.sh stop
查看狀態: ./zkServer.sh status

dubbo入門

項目準備

首先創建兩個項目

引入依賴

<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>
  </dependencies>

再配置兩個tomcat，名字與兩個項目相同

服務提供者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>

服務提供者dubbo配置文件

創建applicationContext-dao.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">
    <!--給當前項目服務起名-->
    <dubbo:application name="dubboxdemo-service"/>
    <!--配置連接zookeeper的ip和端口-->
    <dubbo:registry address="zookeeper://192.168.200.128:2181"/>
    <!--包掃描，在這個包下面的實現類中使用@Service註解纔會生效-->
    <dubbo:annotation package="cn.itcast.service" />
</beans>

服務消費者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>

服務消費者dubbo配置文件

<?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">

    <!--註解驅動-->
    <mvc:annotation-driven >
        <!--轉換器，將傳輸的字符串強制轉換成utf-8編碼-->
        <mvc:message-converters register-defaults="false">
            <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                <constructor-arg value="UTF-8" />
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>


    <!--給當前項目起名-->
    <dubbo:application name="dubboxdemo-web" />
    <!--配置連接zookeeper-->
    <dubbo:registry address="zookeeper://192.168.200.128:2181"/>
    <!--配置包掃描，只有在這個包下面纔可以注入service-->
    <dubbo:annotation package="cn.itcast.controller" />
</beans>

測試

TestController

package cn.itcast.controller;

import cn.itcast.service.TestService;
import com.alibaba.dubbo.config.annotation.Reference;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

/**
 * @RestController註解作用：相當於在類上加上@Controller註解，並且在類的所以方法上@ResponseBody註解
 */
@RestController
@RequestMapping("/test")
public class TestController {
    @Reference
    private TestService testService;

    @RequestMapping("/getName")
    public String getName(){
        String name = testService.getName();
        return name;
    }
}

TestService（接口省略）

package cn.itcast.service.impl;

import cn.itcast.service.TestService;
import com.alibaba.dubbo.config.annotation.Service;

@Service
public class TestServiceImpl implements TestService {

    @Override
    public String getName() {
        return "zhangsan";
    }
}