JavaEE学习日志(一百一十一): 分布式项目基本构建（Dubbo和Zookeeper）

SOA架构

Tomcat极限: 单台Tomcat极限基本是可以同时抗住500个并发.

传统行业项目: 并发低, 数据量小, 不需要高可用, 例如: oa, erp, crm项目, 或者政府项目, 银行项目等.
互联网项目: 高并发, 大数据量, 高可用 例如: 京东, 百度, 淘宝, 天猫, 饿了么, 美团, 滴滴, ofo, 钉钉

soa架构也叫分布式架构，由互联网项目使用

Dubbo

dubbo作用
跨项目调用方法, 例如从A项目中的controller调用B项目中的service方法

dubbo同类型的技术都有哪些
rpc协议实现框架: dubbo, dubbox, springCloud

• 优点: 传输效率快
• 缺点: controller和service两个项目必须都是Java语言实现

webService技术: 代表框架有cxf
底层使用的协议叫做soap协议, 其实传输的就是xml数据

• 优点: 可以跨语言跨平台, controller可以是Java语言实现, service可以是.net或者C语言等语言实现
• 缺点: 传输效率低

dubbo用法

• service实现类上写@Service注解, 注意这个@Service注解不是spring包的是阿里的dubbo包下的
• controller注入的时候使用@Refrence注解来进行注入, 也是阿里dubbo包下面的.
• 如果controller和service之间传输pojo实体类, 那么实体类必须实现Java的序列化接口

dubbo调用流程

Zookeeper

在linux下安装zookeeper

安装完成

将目录改成zookeeper

查看zoo.cfg配置文件


启动zookeeper

zookeeper命令:
启动: ./zkServer.sh start
关闭: ./zkServer.sh stop
查看状态: ./zkServer.sh status

dubbo入门

项目准备

首先创建两个项目

引入依赖

<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相关 -->
    <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>

再配置两个tomcat，名字与两个项目相同

服务提供者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">
  <!-- 加载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>

服务提供者dubbo配置文件

创建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">
    <!--给当前项目服务起名-->
    <dubbo:application name="dubboxdemo-service"/>
    <!--配置连接zookeeper的ip和端口-->
    <dubbo:registry address="zookeeper://192.168.200.128:2181"/>
    <!--包扫描，在这个包下面的实现类中使用@Service注解才会生效-->
    <dubbo:annotation package="cn.itcast.service" />
</beans>

服务消费者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">
  <!-- 解决post乱码 -->
  <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>
    <!-- 指定加载的配置文件 ，通过参数contextConfigLocation加载-->
    <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>

服务消费者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">

    <!--注解驱动-->
    <mvc:annotation-driven >
        <!--转换器，将传输的字符串强制转换成utf-8编码-->
        <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>


    <!--给当前项目起名-->
    <dubbo:application name="dubboxdemo-web" />
    <!--配置连接zookeeper-->
    <dubbo:registry address="zookeeper://192.168.200.128:2181"/>
    <!--配置包扫描，只有在这个包下面才可以注入service-->
    <dubbo:annotation package="cn.itcast.controller" />
</beans>

测试

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注解作用：相当于在类上加上@Controller注解，并且在类的所以方法上@ResponseBody注解
 */
@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";
    }
}