Java RPC 程式設計：Motan 實現示例，叢集配置
阿新 • • 發佈：2019-01-05
在多個伺服器程序之間的通訊，目前使用的技術一般是 RPC（Remote Procedure Call Protocol，遠端過程呼叫協議）。
使用 RPC 可以訪問遠端主機的程序服務，不需要清楚底層網路通訊機制，只需要關注服務本身即可。RPC 是目前分散式開發技術中一種常用的技術，其在分散式開發中能更簡單地呼叫遠端服務，就像本地開發一樣。
Motan 是新浪微博開源的 RPC 輕量級框架，其底層網路通訊使用了 Netty 網路框架，序列化協議支援 Hessian 和 Java 的序列化，網路通訊協議可以支援 Motan、Http、TCP 等。
Motan Github 連結：
建立 webapp 專案參見連結：https://blog.csdn.net/qq_39384184/article/details/85406037
新增 pom 依賴
<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/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.youyoo</groupId> <artifactId>Motan</artifactId> <packaging>war</packaging> <version>1.0</version> <name>Motan Maven Webapp</name> <url>http://maven.apache.org</url> <repositories> <repository> <id>spy</id> <name>36</name> <layout>default</layout> <url>http://repo1.maven.org/maven2</url> <snapshots> <enabled>false</enabled> </snapshots> </repository> </repositories> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>3.8.1</version> <scope>test</scope> </dependency> <!--Motan--> <dependency> <groupId>com.weibo</groupId> <artifactId>motan-core</artifactId> <version>0.0.1</version> </dependency> <dependency> <groupId>com.weibo</groupId> <artifactId>motan-transport-netty</artifactId> <version>0.0.1</version> </dependency> <!-- 叢集相關 --> <!-- consul --> <dependency> <groupId>com.weibo</groupId> <artifactId>motan-registry-consul</artifactId> <version>0.0.1</version> </dependency> <!-- zookeeper --> <dependency> <groupId>com.weibo</groupId> <artifactId>motan-registry-zookeeper</artifactId> <version>0.0.1</version> </dependency> <!-- dependencies blow were only needed for spring-based features --> <dependency> <groupId>com.weibo</groupId> <artifactId>motan-springsupport</artifactId> <version>0.0.1</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>4.0.5.RELEASE</version> </dependency> </dependencies> <build> <finalName>Motan</finalName> </build> </project>
為服務方的呼叫方建立介面
- FooService
package server; import java.util.List; import java.util.Map; public interface FooService { String hello(String name); int helloInt(int number1); double helloDouble(double number2); List<String> helloList(List<String> list); Map<String, List<String>> helloMap(Map<String, List<String>> map); DemoBean helloJavabean(DemoBean bean); }
- DemoBean
package server;
import java.io.Serializable;
public class DemoBean implements Serializable {
private static final long serialVersionUID = -8088381880917660322L;
private long id;
private String name;
private double score;
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getScore() {
return score;
}
public void setScore(double score) {
this.score = score;
}
}
服務方實現這個介面的邏輯
- FooServiceImpl
package server;
import java.util.List;
import java.util.Map;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class FooServiceImpl implements FooService {
public static void main(String[] args) throws InterruptedException {
ApplicationContext applicationContext = new ClassPathXmlApplicationContext(
"classpath:motan_server.xml");
System.out.println("server start...");
}
public String hello(String name) {
System.out.println("invoked rpc service " + name);
return "hello " + name;
}
public int helloInt(int number1) {
System.out.println("invoked rpc service " + number1);
return number1;
}
public double helloDouble(double number2) {
System.out.println("invoked rpc service " + number2);
return number2;
}
public List<String> helloList(List<String> list) {
System.out.print("invoked rpc service ");
for (String string : list) {
System.out.print(string + ",");
}
System.out.println();
return list;
}
public Map<String, List<String>> helloMap(Map<String, List<String>> map) {
System.out.print("invoked rpc service ");
for (String key : map.keySet()) {
System.out.print(key + ":[");
for (String list : map.get(key)) {
System.out.print(list + ",");
}
System.out.print("],");
}
System.out.println();
return map;
}
public DemoBean helloJavabean(DemoBean bean) {
System.out.print("invoked rpc service " + bean);
System.out.print("," + bean.getId());
System.out.print("," + bean.getName());
System.out.print("," + bean.getScore());
System.out.println();
return bean;
}
}
配置服務方暴露介面
- motan_server.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:motan="http://api.weibo.com/schema/motan"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://api.weibo.com/schema/motan http://api.weibo.com/schema/motan.xsd">
<!-- service implemention bean -->
<bean id="serviceImpl" class="server.FooServiceImpl"/>
<!-- exporting service by motan -->
<motan:service interface="server.FooService" ref="serviceImpl"
export="8002"/>
<!--叢集配置：registry 定義-->
<!--consul-->
<!--<motan:registry regProtocol="consul" name="my_consul"-->
<!--address="127.0.0.1:8003"></motan:registry>-->
<!--consul server-->
<!--<motan:service interface="server.FooService" ref="serviceImpl"-->
<!--registry="my_consul" export="8002"/>-->
<!--zookeeper 單節點-->
<!--<motan:registry regProtocol="zookeeper" name="my_zookeeper"-->
<!--address="127.0.0.1:2181"></motan:registry>-->
<!--zookeeper 多節點叢集-->
<!--<motan:registry regProtocol="zookeeper" name="my_zookeeper"-->
<!--address="127.0.0.1:2181,127.0.0.1:2182,127.0.0.1:2183"></motan:registry>-->
<!--zookeeper server-->
<!--<motan:service interface="server.FooService" ref="serviceImpl"-->
<!--registry="my_zookeeper" export="8002"/>-->
</beans>
配置呼叫方呼叫介面
- client_server.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:motan="http://api.weibo.com/schema/motan"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://api.weibo.com/schema/motan http://api.weibo.com/schema/motan.xsd">
<!-- reference to the remote service -->
<motan:referer id="remoteService" interface="server.FooService"
directUrl="localhost:8002"/>
<!--叢集配置：registry 定義-->
<!--consul-->
<!--<motan:registry regProtocol="consul" name="my_consul"-->
<!--address="127.0.0.1:8500"></motan:registry>-->
<!--consul client-->
<!--<motan:referer id="remoteService"-->
<!--interface="server.FooService"-->
<!--registry="my_consul"></motan:referer>-->
<!--zookeeper 單節點-->
<!--<motan:registry regProtocol="zookeeper" name="my_zookeeper"-->
<!--address="127.0.0.1:2181"></motan:registry>-->
<!--zookeeper 多節點叢集-->
<!--<motan:registry regProtocol="zookeeper" name="my_zookeeper"-->
<!--address="127.0.0.1:2181,127.0.0.1:2182,127.0.0.1:2183"></motan:registry>-->
<!--zookeeper client-->
<!--<motan:referer id="remoteService"-->
<!--interface="server.FooService"-->
<!--registry="my_zookeeper"></motan:referer>-->
</beans>
呼叫方呼叫
- Client
package client;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.ArrayList;
import java.util.Map;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import server.DemoBean;
import server.FooService;
public class Client {
public static void main(String[] args) throws InterruptedException {
ApplicationContext ctx = new ClassPathXmlApplicationContext(
"classpath:motan_client.xml");
// 獲取到service
FooService service = (FooService) ctx.getBean("remoteService");
// rpc呼叫
/** String **/
String ret1 = service.hello("motan");
System.out.println(ret1);
/** int **/
int ret2 = service.helloInt(110);
System.out.println(ret2);
/** double **/
double ret3 = service.helloDouble(11.2);
System.out.println(ret3);
/** list **/
List<String> list = new ArrayList<String>();
list.add("hello");
list.add("motan");
List<String> ret4 = service.helloList(list);
for (String string : ret4) {
System.out.print(string + ",");
}
System.out.println();
/** map **/
Map<String, List<String>> map = new HashMap<String, List<String>>();
map.put("key1", Arrays.asList(new String[] { "val1","val2" }));
map.put("key2", Arrays.asList(new String[] { "val1","val2","val3" }));
map.put("key3", Arrays.asList(new String[] { "val1","val2","val3","val4" }));
Map<String, List<String>> ret5 = service.helloMap(map);
for (String key : ret5.keySet()) {
System.out.print(key + ":[");
for (String tmp : map.get(key)) {
System.out.print(tmp + ",");
}
System.out.print("],");
}
System.out.println();
/** javabean **/
DemoBean bean = new DemoBean();
bean.setId(1001l);
bean.setName("motan bean");
bean.setScore(99.998);
DemoBean ret6 = service.helloJavabean(bean);
System.out.print(ret6.getId());
System.out.print("," + ret6.getName());
System.out.print("," + ret6.getScore());
System.out.println();
}
}
Motan 的服務方建立好服務介面之後，將暴露介面、埠等在配置檔案中寫好，啟動配置檔案即可開啟，呼叫方需要使用與服務方相同的介面（包括包名相同），並正確配置配置檔案，即可在程式碼中呼叫服務方暴露的介面服務。
叢集配置
實現叢集呼叫只需要在上述操作的基礎上做一點改變即可，Motan 的叢集與阿里的 Dubbo 的原理類似，通過註冊方、服務方、呼叫方三方實現。
- RPC Sever 向 RPC Registry 註冊服務，並每隔一定時間向 RPC Registry 傳送心跳彙報狀態。
- RPC Client 需要向 RPC Registry 訂閱 RPC 服務，RPC Client 根據 RPC Registry 返回的服務列表，對具體的 RPC Server 進行 RPC 呼叫。
- 當 RPC Server 發生變更時，RPC Registry 會同步變更，RPC Client 感知後會對本地的服務列表作相應調整。
Motan 支援 consul 和 Zookeeper 兩種外部伺服器發現元件，實現方式見上述程式碼的註釋：需要新增 pom 依賴和在 server 和 client 的配置檔案中增加 registry 的定義。
consul 需要顯示呼叫心跳開關注冊到 consul（zookeeper 不需要）。
MotanSwitcherUtil.setSwitcher(ConsulConstants.NAMING_PROCESS_HEARTBEAT_SWITCHER,true);