一、dubbo 服务化最佳实践
1. 分包
建议将服务接口、服务模型、服务异常等均放在公共包中
2. 粒度
服务接口尽可能大粒度,每个服务方法应代表一个功能,而不是某功能的一个步骤,否则将面临分布式事务问题,Dubbo 暂未提供分布式事务支持
服务接口建议以业务场景为单位划分,并对相近业务做抽象,防止接口数量爆炸
不建议使用过于抽象的通用接口,如:Map query(Map),这样的接口没有明确语义,会给后期维护带来不便
3. 版本
每个接口都应定义版本号,为后续不兼容升级提供可能,如: <dubbo:service interface="com.xxx.XxxService" version="1.0" />。
建议使用两位版本号,要变更服务版本。先升级一半提供者为新版本,再将消费者全部升为新版本,然后将剩下的一半提供者升为新版本
二、改造 dubbo 项目
抽象分散在多个项目中的公共接口,实体类,异常,工具类到一个项目中(比如:link-interface)
在其他项目如服务提供者,消费者共用公共的资源
三、link-interface
link-interface是一个maven Java工程
dubbo官方推荐使用的一个模式,将实体bean和业务接口存放到接口工程中
1. pom.xml
这只是一个java工程,这里不用改变
<?xml version="1.0" encoding="UTF-8"?>
<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>com.md.dubbo</groupId>
<artifactId>03-link-interface</artifactId>
<version>1.0.0</version>
</project>
2. 实体类
package com.md.dubbo.model;
import java.io.Serializable;
/**
* @author MD
* @create 2020-08-19 10:40
*/
// 对于分布式开发,对象要进行序列化操作
public class User implements Serializable {
private Integer id;
private String username;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
}
3. 公共接口
package com.md.dubbo.service;
import com.md.dubbo.model.User;
/**
* @author MD
* @create 2020-08-19 10:41
*/
public interface UserService {
/**
* 通过用户id获取用户信息
* @param id
* @return
*/
User queryUserById(Integer id);
/**
* 获取用户总人数
* @return
*/
Integer queryAllUserCount();
}
四、提供者
建立maven web工程
1. pom.xml
注意引入接口工程的依赖
<?xml version="1.0" encoding="UTF-8"?>
<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>com.md.dubbo</groupId>
<artifactId>04-link-userservice-provider</artifactId>
<version>1.0.0</version>
<packaging>war</packaging>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<!--spring依赖-->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.3.16.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>4.3.16.RELEASE</version>
</dependency>
<!--dubbo依赖-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>dubbo</artifactId>
<version>2.6.2</version>
</dependency>
<!--引入接口工程-->
<dependency>
<groupId>com.md.dubbo</groupId>
<artifactId>03-link-interface</artifactId>
<version>1.0.0</version>
</dependency>
</dependencies>
<build>
</build>
</project>
2. 接口实现
这里只是一个简单的模拟
package com.md.dubbo.service.impl;
import com.md.dubbo.model.User;
import com.md.dubbo.service.UserService;
/**
* @author MD
* @create 2020-08-19 10:48
*/
public class UserServiceImpl implements UserService {
@Override
public User queryUserById(Integer id) {
User user = new User();
user.setId(id);
user.setUsername("山丘!");
return user;
}
@Override
public Integer queryAllUserCount() {
return 9;
}
}
3. 服务提供者的核心配置文件
在resources目录下建立dubbo-userservice-provider.xml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:dubbo="http://dubbo.apache.org/schema/dubbo"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://dubbo.apache.org/schema/dubbo http://dubbo.apache.org/schema/dubbo/dubbo.xsd">
<!--声明dubbo服务提供者名称:保证唯一性,通常用model名就可以-->
<dubbo:application name="04-link-userservice-provider"/>
<!--设置dubbo使用的协议和端口号-->
<dubbo:protocol name="dubbo" port="20880"/>
<!--暴露服务接口-->
<dubbo:service interface="com.md.dubbo.service.UserService" ref="userService" registry="N/A"/>
<!--加载业务接口的实现类到spring容器中-->
<bean id="userService" class="com.md.dubbo.service.impl.UserServiceImpl"/>
</beans>
4. 添加监听器
在web.xml中
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<!--默认的版本低的话换成这个版本的,直接复制即可-->
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:dubbo-userservice-provider.xml</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
</web-app>
5. 配置Tomcat
端口号注意修改一下:避免冲突
HTTP port :8081
JMX port:1098
五、消费者
1. pom.xml
还是maven web项目
注意:添加了接口的依赖
<?xml version="1.0" encoding="UTF-8"?>
<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>com.md.dubbo</groupId>
<artifactId>05-link-consumer</artifactId>
<version>1.0.0</version>
<packaging>war</packaging>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<!--spring依赖-->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.3.16.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>4.3.16.RELEASE</version>
</dependency>
<!--dubbo依赖-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>dubbo</artifactId>
<version>2.6.2</version>
</dependency>
<!--接口工程-->
<!--此时不像之前的还得打jar包,这里不用,03是普通的java工程,只提供接口-->
<dependency>
<groupId>com.md.dubbo</groupId>
<artifactId>03-link-interface</artifactId>
<version>1.0.0</version>
</dependency>
</dependencies>
<build>
</build>
</project>
2. 服务消费者的核心配置文件
在resources目录下建立dubbo-consumer.xml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:dubbo="http://dubbo.apache.org/schema/dubbo"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://dubbo.apache.org/schema/dubbo http://dubbo.apache.org/schema/dubbo/dubbo.xsd">
<!--声明服务消费着名称:唯一-->
<dubbo:application name="05-link-consumer"/>
<!--引用远程接口服务-->
<dubbo:reference id="userService" interface="com.md.dubbo.service.UserService"
url="dubbo://localhost:20880"
registry="N/A"/>
</beans>
3. controller
package com.md.dubbo.web;
import com.md.dubbo.model.User;
import com.md.dubbo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
/**
* @author MD
* @create 2020-08-19 11:11
*/
@Controller
public class UserController {
@Autowired
private UserService userService;
@RequestMapping(value = "/userDetail")
public String userDetail(Model model,Integer id){
// 根据id获取用户信息
User user = userService.queryUserById(id);
// 获取用户总人数
Integer allUserCount = userService.queryAllUserCount();
model.addAttribute("user",user);
model.addAttribute("allUserCount",allUserCount);
return "userDetail";
}
}
4. applicationContext.xml
在resources目录下创建spring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:context="http://www.springframework.org/schema/context"
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/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!--扫描组件-->
<context:component-scan base-package="com.md.dubbo.web"/>
<!--配置注解驱动-->
<mvc:annotation-driven/>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/"/>
<property name="suffix" value=".jsp"/>
</bean>
</beans>
5. 配置中央调度器
在web.xml中
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<!--中央调度器-->
<servlet>
<servlet-name>dispatcherServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:applicationContext.xml,classpath:dubbo-consumer.xml</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>dispatcherServlet</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
6. 配置Tomcat
此时使用默认的就可以了
7. 配置测试页面
在webapp下 建立userDetail.jsp
<%--
Created by IntelliJ IDEA.
User: MD
Date: 2020/8/19
Time: 11:16
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<h1>hello Dubbo</h1>
<h2>用户id:${user.id}</h2>
<h2>用户姓名:${user.username}</h2>
<h2>用户总数:${allUserCount}</h2>
</body>
</html>
8. 测试
- 首先开服务提供者的Tomcat
- 然后开服务消费者的Tomcat
- 然后在地址栏输入,就可以看到了