分布式系统架构实战demo:SSM+Dubbo

缺乏、安全感 2021-09-26 21:50 338阅读 0赞

对于传统的单一构架，也就是打成的war或者ear包部署在同一个Web容器里的构架，它虽然开发、测试、部署简单，但随着业务的不断发展，维护成本增加，可扩展性差，而且一台Tomcat的并发数在500左右，系统性能存在瓶颈。虽然互联网应用的系统性能瓶颈存在于每一个地方（数据库，网络等），先不考虑其他系统瓶颈，本文采用多Tomcat来解决一个Tomcat带来的瓶颈问题，那么多个Tomcat之间如何通信？答案是Dubbo。

为什么要使用Dubbo?两台服务器A、B，分别部署不同的应用a,b。当A服务器想要调用B服务器上应用b提供的函数或方法的时候，由于不在一个内存空间，不能直接调用，需要通过网络来表达调用的语义传达调用的数据。--[RPC][]。 Dubbo是基于RPC的高性能和透明化的RPC远程服务调用方案。

Dubbo也是一个被国内互联网公司广泛使用的SOA（核心理念：对外提供服务）基础框架，说的直白点就是：一次开发出来的服务接口，相关服务都能调用。很像Java经典的特性：一次编译，到处运行。

开发环境：

Window 7 64；Eclipse-Jee-mars-2-win32-x86\_64 ；Apache-Maven-3.3.9；Spring 4.1.3；Mybatis 3.2.7；Springmvc 4.1.3；Dubbo 2.5.3，开发工具和源码：[http://pan.baidu.com/s/1pLdoe0r][http_pan.baidu.com_s_1pLdoe0r]

源码博主也上传到了'码云'上:[https://gitee.com/liugh\_develop/ssm\_dubbo][https_gitee.com_liugh_develop_ssm_dubbo]

系统构架如下：

![175932_7Uv4_3577599.png][]

## 1.配置环境,创建项目工程 ##

配置开发环境不再这里做赘述,可以参考:[Eclipse+Tomcat+MAVEN+SVN项目完整环境搭建][Eclipse_Tomcat_MAVEN_SVN]

需要注意的是本文所用JDK是1.7,Tomcat是7.0。

####       1.1  mysql安装 ####

数据库环境搭建吐血推荐，博主在踩了很多坑之后总结的高效安装方法。[一分钟快速安装MySQL，超简单。][MySQL]

Mysql链接工具Navicat安装后，打开Navicat，新建连接-->新建数据库Mysql-->双击进入数据库-->查询-->新建查询:

SET FOREIGN_KEY_CHECKS=0;
    
    
    DROP TABLE IF EXISTS `book`;
    CREATE TABLE `book` (
      `book_id` varchar(100) NOT NULL COMMENT '图书ID',
      `book_name` varchar(100) DEFAULT NULL COMMENT '图书名称',
      `number` int(11) DEFAULT NULL COMMENT '馆藏数量',
      PRIMARY KEY (`book_id`)
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='图书表';
    
    
    INSERT INTO `book` VALUES ('1000', 'Java程序设计', '10');
    INSERT INTO `book` VALUES ('1001', '数据结构', '10');
    INSERT INTO `book` VALUES ('1002', '设计模式', '10');
    INSERT INTO `book` VALUES ('1003', '编译原理', '10');

####       1.3  创建父工程和子工程，目录结构如下： ####

![223659_qtM4_3577599.png][]

其中，parent是pom文件的父工程，common是jar包，里面存放interface，bean，dao等公用内容。

controller控制层和service业务层是war包,也就是各分为一个Tomcat。

创建父工程：

![222010_6VMp_3577599.png][]

![222702_3qJW_3577599.png][]

创建common工程,在Packaging时选择jar:

![222415_nIpI_3577599.png][]

创建controller和service的步骤和common一样,不过Packaging选择war，完成后会出现以下报错：

![223523_ktXr_3577599.png][]

原因是webapp下没有WEB\_INF文件夹和web.xml文件，自己创建web.xml,它内容在下文2.1中,复制粘贴即可。注意，此时的运行环境是jdk1.5，需要永久切换成jdk1.7(点buildPath切换1.7的运行环境,下回打开还是jdk1.5).所以在所有的pom文件中加入

<build>
    		<plugins>
    			<plugin>
    				<groupId>org.apache.maven.plugins</groupId>
    				<artifactId>maven-compiler-plugin</artifactId>
    				<version>3.2</version>
    				<configuration>
    					<source>1.7</source>
    					<target>1.7</target>
    					<encoding>UTF-8</encoding>
    				</configuration>
    			</plugin>
    		</plugins>
    	</build>

加入后会有以下报错,根据如下图片中步骤处理即可:

![224845_TJB1_3577599.png][]

####       1.4  导入jar包。 ####

parent项目pom.xml导入所有jar包的坐标，service和controller会依赖common,所以在common的pom文件中加入要引入的jar包。因为太长，此处省略源码，读者可以下载源码查看。

因为公用jar放在了common里，所以在controller和service的pom,xml文件中都加入common的依赖：

<dependencies>
      	<dependency>
      		 <groupId>com.test</groupId>
        	<artifactId>test-common</artifactId>
        	<version>0.0.1-SNAPSHOT</version>
      	</dependency>
      </dependencies>

## 2.整合Spring+Mybatis ##

####       2.1  配置Spring监听器 ####

一般会整合Spring+Mybatis放在业务逻辑层service。在service的web.xml中加入:

####       2.2  创建上下文配置文件: spring-context.xml ####

####       2.3创建数据源和配置文件jdbc.xml: ####

![080604_Xjfi_3577599.png][]

jdbc.xml中加入读取配置文件-->数据源-->事务管理-->Spring声明式事务管理配置:

<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:task="http://www.springframework.org/schema/task" xmlns:dubbo="http://code.alibabatech.com/schema/dubbo" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-4.0.xsd http://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd">
    	
    	
    	<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    		<property name="locations">
    			<list>
    				<value>classpath:jdbc.properties</value>
    			</list>
    		</property>
    	</bean>
    		
    	  
    	<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" destroy-method="close">
    		<property name="driverClassName" value="com.mysql.jdbc.Driver" />
    		<property name="url" value="${jdbc.url}" />
    		<property name="username" value="${jdbc.username}" />
    		<property name="password" value="${jdbc.password}" />
    		<property name="initialSize" value="${jdbc.initialSize}"></property>
    		<property name="maxActive" value="${jdbc.maxActive}"></property>
    		<property name="minIdle" value="1"></property>
    		<property name="maxWait" value="30000"></property>
    		<property name="timeBetweenEvictionRunsMillis" value="60000"></property>
    		<property name="minEvictableIdleTimeMillis" value="300000"></property>
    		<property name="validationQuery" value="SELECT 1 "></property>
    		<property name="testWhileIdle" value="true"></property>
    		<property name="poolPreparedStatements" value="true"></property>
    		<property name="maxPoolPreparedStatementPerConnectionSize" value="20"></property>
    		<property name="filters" value="stat,slf4j" />
    		<property name="proxyFilters">
    			<list>
    				<ref bean="stat-filter" />
    				<ref bean="log-filter" />
    			</list>
    		</property>
    	</bean>
    	
    	<bean id="log-filter" class="com.alibaba.druid.filter.logging.Slf4jLogFilter">
    		<property name="resultSetLogEnabled" value="true" />
    		<property name="statementExecutableSqlLogEnable" value="true" />
    	</bean>
    
    	<bean id="stat-filter" class="com.alibaba.druid.filter.stat.StatFilter">
    		<property name="slowSqlMillis" value="30000" />
    		<property name="logSlowSql" value="true" />
    		<property name="mergeSql" value="true" />
    	</bean>
    	
    	<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
    		<property name="dataSource" ref="dataSource"/>
    	</bean>
    	 
    	<tx:advice id="txAdvice" transaction-manager="transactionManager">
    		<tx:attributes>
    			<tx:method name="select*" read-only="true" propagation="REQUIRED"/>
    			<tx:method name="find*" read-only="true" propagation="REQUIRED"/>
    			<tx:method name="query*" read-only="true" propagation="REQUIRED"/>
    			<tx:method name="get*" read-only="true" propagation="REQUIRED"/>
    			<tx:method name="search*" read-only="true" propagation="REQUIRED"/>
    			<tx:method name="is*" read-only="true" propagation="REQUIRED"/>
    			<tx:method name="save*" propagation="REQUIRED" rollback-for="Exception,RuntimeException"/>
    			<tx:method name="create*" propagation="REQUIRED" rollback-for="Exception,RuntimeException"/>
    			<tx:method name="update*" propagation="REQUIRED" rollback-for="Exception,RuntimeException"/>
    			<tx:method name="add*" propagation="REQUIRED" rollback-for="Exception,RuntimeException"/>
    			<tx:method name="delete*" propagation="REQUIRED" rollback-for="Exception,RuntimeException"/>
    			<tx:method name="execute*" propagation="REQUIRED" rollback-for="Exception,RuntimeException"/>
    			<tx:method name="remove*" propagation="REQUIRED" rollback-for="Exception,RuntimeException"/>
    			<tx:method name="put*" propagation="REQUIRED" rollback-for="Exception,RuntimeException"/>
    			<tx:method name="import*" propagation="REQUIRED" rollback-for="Exception,RuntimeException"/>
    			<tx:method name="submit*" propagation="REQUIRED" rollback-for="Exception,RuntimeException"/>
    			<tx:method name="cancel*" propagation="REQUIRED" rollback-for="Exception,RuntimeException"/>
    			<tx:method name="send*" propagation="REQUIRED" rollback-for="Exception,RuntimeException"/>
    			<tx:method name="edit*" propagation="REQUIRED" rollback-for="Exception,RuntimeException"/>
    			<tx:method name="handle*" propagation="REQUIRED" rollback-for="Exception,RuntimeException"/>
    			<tx:method name="close*" propagation="REQUIRED" rollback-for="Exception,RuntimeException"/>
    			<tx:method name="export*" propagation="REQUIRED" rollback-for="Exception,RuntimeException"/>
    		</tx:attributes>
    	</tx:advice>
    	
    	<aop:config>
    		<aop:pointcut id="transactionPointcut" expression="execution(* com.test..*ServiceImpl.*(..))" />
    		<aop:advisor pointcut-ref="transactionPointcut" advice-ref="txAdvice" />
    	</aop:config>
    </beans>

此处的Spring声明式事务管理配置是上一篇具体应用,有兴趣的可以深入理解下AOP:[ Spring AOP是什么?你都拿它做什么?][Spring AOP]

####       2.4  创建spring-common-context.xml自动扫描 ####

####       2.5  配置Mybatis ####

在config下创建mybatis.xml-->加入sqlSessionFactory 工厂-->接口的Mapper自动扫描方式:

####          2.6 配置mybatis-config.xml ####

在src/main/resources下创建,并加入如下配置:

<?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
    
    <configuration>
    	
    	<typeAliases>
    		<package name="com.test.core.bean"/>
    	</typeAliases>
    </configuration>

接着创建mapper目录如下:

![085330_xUmo_3577599.png][]

####       2.7  测试spring+mybatis. ####

创建JavaBean的TestBook.java:

package com.test.core.bean;
    
    import java.io.Serializable;
    
    public class TestBook implements Serializable{
    	private static final long serialVersionUID = 1L;
    	String bookId;
        String bookName;
        Integer number;
    	public String getBookId() {
    		return bookId;
    	}
    	public void setBookId(String bookId) {
    		this.bookId = bookId;
    	}
    	public String getBookName() {
    		return bookName;
    	}
    	public void setBookName(String bookName) {
    		this.bookName = bookName;
    	}
    	public Integer getNumber() {
    		return number;
    	}
    	public void setNumber(Integer number) {
    		this.number = number;
    	}
    	@Override
    	public String toString() {
    		return "TestBean [bookId=" + bookId + ", bookName=" + bookName + ", number=" + number + "]";
    	}
    }

Dao接口的TestBookDao:

package com.test.core.dao;
    
    import com.test.core.bean.TestBook;
    
    public interface TestBookDao {
    
    	public TestBook findById(String id);
    }

Mapper文件:创建包-->加入TestBookDao.xml文件:

<?xml version="1.0" encoding="UTF-8" ?>  
    <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
    
    
    <mapper namespace="com.test.core.dao.TestBookDao">
    
    	
    	<select id="findById" resultType="TestBook" parameterType="java.lang.String">
    		select book_id bookId,book_name bookName,number from book where book_id= #{bookId}
    	</select>
    	
    </mapper>

测试:

package com.test.core.testDemo;
    
    import org.junit.Test;
    import org.junit.runner.RunWith;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.test.context.ContextConfiguration;
    import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
    
    import com.test.core.bean.TestBook;
    import com.test.core.dao.TestBookDao;
    
    @RunWith(SpringJUnit4ClassRunner.class)
    @ContextConfiguration(locations = {
       "classpath:spring-context.xml"})
    public class TestSpringMybatis {
    	
    	@Autowired
    	TestBookDao testBookDao;
    	@Test
    	public void testFind(){
    		TestBook findById = testBookDao.findById("1000");
    		System.out.println(findById.toString());
    	}
    }

测试结果:

![084852_l83x_3577599.png][]

## 3.整合springmvc ##

整合SpringMVC一般放在controller层。

####       3.1  配置前端控制器DispatcherServlet ####

在子项目controller中找到web.xml文件,加入:

<?xml version="1.0" encoding="UTF-8"?>
    <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
    		
    	<servlet>
    		<servlet-name>controller</servlet-name>
    		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    		<init-param>
    			
    			<param-name>contextConfigLocation</param-name>
    			<param-value>classpath:springmvc-controller.xml</param-value>
    		</init-param>
    		<load-on-startup>1</load-on-startup>
    	</servlet>
    	
    	<servlet-mapping>
    		
    		 <servlet-name>controller</servlet-name>
    		 <url-pattern>/</url-pattern>
    	</servlet-mapping>
    </web-app>

####       3.2  配置扫描包,前端控制器,处理器映射器,处理器适配器,视图解析器 ####

在classpath的SpringMVC-controller.xml中:

####       3.3 加入Log日志打印 ####

在controller和service子项目的src/main/resources中创建log4j.properties加入:

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

####       3.4  测试SpringMVC ####

创建Tomcat:

![092727_bhoK_3577599.png][]

配置service和controller的Tomcat:

![092230_FUQQ_3577599.png][]

注意两个Tomcat端口号不要重复,且启动时间设置长点:

![101310_LDJ5_3577599.png][]

创建测试的controller和jsp:

package com.test.core.controller;
    
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    
    @Controller
    public class TestBookController {
    
    	@RequestMapping(value="/index.do")
    	public String index(){
    		return "index";
    	}
    }

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Insert title here</title>
    </head>
    <body>
    	hello springmvc
    </body>
    </html>

在这里只用启动controller的Tomcat,并在浏览器中输入:http://localhost:8080/index.do

![092342_hkZw_3577599.png][]

## 4.整合Dubbo ##

![095544_wOn0_3577599.png][]

搭建Zookeeper本文不在赘述,为了方便,Dubbo将设置成直接从本地查找服务.

####       4.1搭建Dubbo服务提供方 ####

在test-service的config文件夹下创建dubbo-provider.xml:

![095012_EcJm_3577599.png][]

Service的TestBookService接口(在common工程里创建)和TestBookServiceImpl实现类(这里只写实现类):

package com.test.core.service;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    import com.test.core.bean.TestBook;
    import com.test.core.dao.TestBookDao;
    
    @Service("testBookService")
    public class TestBookServiceImpl implements TestBookService{
    
    	@Autowired
    	TestBookDao testBookDao;
    	
    	public TestBook findById(String id) {
    		return testBookDao.findById(id);
    	}
    
    }

####       4.2  搭建服务消费方 ####

在test-service项目的springmvc-controller.xml中加入:

src/main/resources下创建dubbo-consumer.xml:

controller内容如下:

![101005_CCJ6_3577599.png][]

####       4.3 测试完整项目 ####

在testDubbo.jsp的body中加入:$\{ requestScope.book\}-->启动service的Tomcat-->启动controller的tomcat(这个必须在service启动之后才能启动,注意端口号不能重复)-->浏览器中输入http://localhost:8080/testDubbo.do?id=1000

![133427_sn5j_3577599.png][]

## 5.项目中可能会遇到的问题: ##

####       5.1  Spring注解@service无法取别名 ####

![104241_nCgw_3577599.png][]

####       5.2  启动Tomcat时： cannot resolve reference to bean等找不到类的报错 ####

在parent上右键-->Run as-->Maven clean

在parent上右键-->Maven-->Update Project

####       5.3  Dubbo的xml文件里有红叉 ####

![这里写图片描述][22115249_Tmgz.jpg]

ref:[使用dubbo时applicationContext.xml报错解决办法][dubbo_applicationContext.xml]

####       5.4   jsp文件头报错 ####

![22115249_bNeW.jpg][]

ref:[新建的web项目的jsp页面报错的解决方法][web_jsp]

[RPC]: https://baike.baidu.com/item/%E8%BF%9C%E7%A8%8B%E8%BF%87%E7%A8%8B%E8%B0%83%E7%94%A8%E5%8D%8F%E8%AE%AE/6893245?fr=aladdin&fromid=609861&fromtitle=RPC
[http_pan.baidu.com_s_1pLdoe0r]: http://pan.baidu.com/s/1pLdoe0r
[https_gitee.com_liugh_develop_ssm_dubbo]: https://gitee.com/liugh_develop/ssm_dubbo
[175932_7Uv4_3577599.png]: https://static.oschina.net/uploads/space/2017/0724/175932_7Uv4_3577599.png
[Eclipse_Tomcat_MAVEN_SVN]: http://www.cnblogs.com/zyw-205520/p/4767633.html
[MySQL]: https://my.oschina.net/liughDevelop/blog/1483695
[223659_qtM4_3577599.png]: https://static.oschina.net/uploads/space/2017/0721/223659_qtM4_3577599.png
[222010_6VMp_3577599.png]: https://static.oschina.net/uploads/space/2017/0721/222010_6VMp_3577599.png
[222702_3qJW_3577599.png]: https://static.oschina.net/uploads/space/2017/0721/222702_3qJW_3577599.png
[222415_nIpI_3577599.png]: https://static.oschina.net/uploads/space/2017/0721/222415_nIpI_3577599.png
[223523_ktXr_3577599.png]: https://static.oschina.net/uploads/space/2017/0721/223523_ktXr_3577599.png
[224845_TJB1_3577599.png]: https://static.oschina.net/uploads/space/2017/0721/224845_TJB1_3577599.png
[080604_Xjfi_3577599.png]: https://static.oschina.net/uploads/space/2017/0722/080604_Xjfi_3577599.png
[Spring AOP]: https://my.oschina.net/liughDevelop/blog/1457097
[085330_xUmo_3577599.png]: https://static.oschina.net/uploads/space/2017/0722/085330_xUmo_3577599.png
[084852_l83x_3577599.png]: https://static.oschina.net/uploads/space/2017/0722/084852_l83x_3577599.png
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