快速入门
实现功能
存在2个系统,A系统和B系统,A系统调用B系统的接口获取数据,用于查询用户列表。
安装zookeeper
解压得到如下:
修改配置文件zoo.cfg: 该目录必须存在。
启动zookeeper服务:
搭建B系统
创建工程
导入依赖
<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.dubbo</groupId>
<artifactId>dubbo-b</artifactId>
<version>1.0.0-SNAPSHOT</version>
<packaging>war</packaging>
<dependencies>
<!-- dubbo采用spring配置方式,所以需要导入spring容器依赖 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>4.1.3.RELEASE</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.6.4</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>dubbo</artifactId>
<version>2.5.3</version>
<exclusions>
<exclusion>
<!-- 排除传递spring依赖 -->
<artifactId>spring</artifactId>
<groupId>org.springframework</groupId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.tomcat.maven</groupId>
<artifactId>tomcat7-maven-plugin</artifactId>
<version>2.2</version>
<configuration>
<port>8181</port>
<path>/</path>
</configuration>
</plugin>
</plugins>
</build>
</project>
配置log4j文件
log4j.properties:
log4j.rootLogger=DEBUG,A1
log4j.appender.A1=org.apache.log4j.ConsoleAppender
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=%-d{yyyy-MM-dd HH:mm:ss,SSS} [%t] [%c]-[%p] %m%n
创建User对象
package cn.itcast.dubbo.pojo;
// 使用dubbo要求传输的对象必须实现序列化接口
public class User implements java.io.Serializable {
private static final long serialVersionUID = -2668999087589887337L;
private Long id;
private String username;
private String password;
private Integer age;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
}
创建UserService(接口)提供查询服务
package cn.itcast.dubbo.service;
import java.util.List;
import cn.itcast.dubbo.pojo.User;
public interface UserService {
/**
* 查询所有的用户数据
*
* @return
*/
public List<User> queryAll();
}
创建UserServiceImpl实现类
package cn.itcast.dubbo.service.impl;
import java.util.ArrayList;
import java.util.List;
import cn.itcast.dubbo.pojo.User;
import cn.itcast.dubbo.service.UserService;
public class UserServiceImpl implements UserService {
/**
* 实现查询,这里做模拟实现,不做具体的数据库查询
*/
public List<User> queryAll() {
List<User> list = new ArrayList<User>();
for (int i = 0; i < 10; i++) {
User user = new User();
user.setAge(10 + i);
user.setId(Long.valueOf(i + 1));
user.setPassword("123456");
user.setUsername("username_" + i);
list.add(user);
}
return list;
}
}
编写dubbo配置文件
具体配置:
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<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p"
xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 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/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://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd">
<!-- 提供方应用信息,用于计算依赖关系 -->
<dubbo:application name="dubbo-b-server" />
<!-- 这里使用的注册中心是zookeeper -->
<dubbo:registry address="zookeeper://127.0.0.1:2181" client="zkclient"/>
<!-- 用dubbo协议在20880端口暴露服务 -->
<dubbo:protocol name="dubbo" port="20880" />
<!-- 将该接口暴露到dubbo中 -->
<dubbo:service interface="cn.itcast.dubbo.service.UserService" ref="userServiceImpl" />
<!-- 将具体的实现类加入到Spring容器中 -->
<bean id="userServiceImpl" class="cn.itcast.dubbo.service.impl.UserServiceImpl" />
</beans>
导入zookeeper依赖
<dependency>
<groupId>org.apache.zookeeper</groupId>
<artifactId>zookeeper</artifactId>
<version>3.3.3</version>
</dependency>
<dependency>
<groupId>com.github.sgroschupf</groupId>
<artifactId>zkclient</artifactId>
<version>0.1</version>
</dependency>
编写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" id="WebApp_ID" version="2.5">
<display-name>dubbo-b</display-name>
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:dubbo/dubbo-*.xml</param-value>
</context-param>
<!--Spring的ApplicationContext 载入 -->
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
启动tomcat
查看tomcat启动日志:
dubbo version: 2.5.3, current host: 127.0.0.1
2018-05-17 14:49:20,819 [localhost-startStop-1] [com.alibaba.dubbo.config.AbstractConfig]-[INFO] [DUBBO] Export dubbo service cn.itcast.dubbo.service.UserService to local registry, dubbo version: 2.5.3, current host: 127.0.0.1
2018-05-17 14:49:20,819 [localhost-startStop-1] [com.alibaba.dubbo.config.AbstractConfig]-[INFO] [DUBBO] Export dubbo service cn.itcast.dubbo.service.UserService to url dubbo://172.20.10.6:20880/cn.itcast.dubbo.service.UserService?anyhost=true&application=dubbo-b-server&dubbo=2.5.3&interface=cn.itcast.dubbo.service.UserService&methods=queryAll&pid=13560&side=provider×tamp=1526539760699, dubbo version: 2.5.3, current host: 127.0.0.1
2018-05-17 14:49:20,819 [localhost-startStop-1] [com.alibaba.dubbo.config.AbstractConfig]-[INFO] [DUBBO] Register dubbo service cn.itcast.dubbo.service.UserService url dubbo://172.20.10.6:20880/cn.itcast.dubbo.service.UserService?anyhost=true&application=dubbo-b-server&dubbo=2.5.3&interface=cn.itcast.dubbo.service.UserService&methods=queryAll&pid=13560&side=provider×tamp=1526539760699 to registry registry://127.0.0.1:2181/com.alibaba.dubbo.registry.RegistryService?application=dubbo-b-server&client=zkclient&dubbo=2.5.3&pid=13560®istry=zookeeper×tamp=1526539760681, dubbo version: 2.5.3, current host: 127.0.0.1
2018-05-17 14:49:20,831 [localhost-startStop-1] [com.alibaba.dubbo.common.extension.ExtensionLoader]-[DEBUG] [DUBBO] package com.alibaba.dubbo.rpc.cluster;
可以看到,已经将UserService服务注册到zookeeper注册中心,协议采用的是dubbo。
搭建A系统
创建工程
导入依赖
<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.dubbo</groupId>
<artifactId>dubbo-a</artifactId>
<version>0.0.1-SNAPSHOT</version>
<dependencies>
<!-- dubbo采用spring配置方式,所以需要导入spring容器依赖 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>4.1.3.RELEASE</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.6.4</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>dubbo</artifactId>
<version>2.5.3</version>
<exclusions>
<exclusion>
<!-- 排除传递spring依赖 -->
<artifactId>spring</artifactId>
<groupId>org.springframework</groupId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.apache.zookeeper</groupId>
<artifactId>zookeeper</artifactId>
<version>3.3.3</version>
</dependency>
<dependency>
<groupId>com.github.sgroschupf</groupId>
<artifactId>zkclient</artifactId>
<version>0.1</version>
</dependency>
</dependencies>
</project>
配置log4j文件
log4j.properties:
log4j.rootLogger=DEBUG,A1
log4j.appender.A1=org.apache.log4j.ConsoleAppender
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=%-d{yyyy-MM-dd HH:mm:ss,SSS} [%t] [%c]-[%p] %m%n
从b系统中拷贝User对象、UserService接口道a系统
编写dubbo配置文件
dubbo-consumer.xml:
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p"
xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 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/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://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd">
<!-- 提供方应用信息,用于计算依赖关系 -->
<dubbo:application name="dubbo-a-consumer" />
<!-- 这里使用的注册中心是zookeeper -->
<dubbo:registry address="zookeeper://127.0.0.1:2181" client="zkclient"/>
<!-- 从注册中心中查找服务 -->
<dubbo:reference id="userService" interface="cn.itcast.dubbo.service.UserService"/>
</beans>
编写UserService测试用例
package cn.itcast.dubbo.service;
import static org.junit.Assert.*;
import java.util.List;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import cn.itcast.dubbo.pojo.User;
public class UserServiceTest {
private UserService userService;
@Before
public void setUp() throws Exception {
ApplicationContext applicationContext = new ClassPathXmlApplicationContext(
"classpath:dubbo/*.xml");
this.userService = applicationContext.getBean(UserService.class);
}
@Test
public void testQueryAll() {
List<User> users = this.userService.queryAll();
for (User user : users) {
System.out.println(user);
}
}
}
查看效果
可以看到,已经查询到10条数据,那么,也就是说A系统通过B系统提供的服务获取到了数据。
解决代码重复问题
通过刚刚的示例我们可以发现,其中User对象和UserService在A系统和B系统中都使用,那么,我们是否应该讲该代码复用呢?
答案是肯定的。
在使用dubbo时,provider需要将提供服务所需要的java代码(bean、interface等)单独打包成jar提供给consumer使用。
创建dubbo-b-api
创建dubbo-b-api作为代码的抽取
将dubbo-b中的pojo和service接口移动到dubbo-b-api中
删掉dubbo-a和dubbo-b的pojo和service
在dubbo-b和dubbo-a的pom.xml文件中添加dubbo-b-api的依赖
<dependency>
<groupId>cn.itcast.dubbo</groupId>
<artifactId>dubbo-b-api</artifactId>
<version>0.0.1-SNAPSHOT</version>
</dependency>
测试
测试,发现,和之前实现一样。