今天分享两者区别：
1、原理方面：
java是一次性加载完毕，浪费资源。
Dubbo是对javaSPI的扩展，以键值对的形式存在，用到哪个实现类取哪一个，而且可以分组，默认注解配置等方式。
2、代码示例：
1）javaspi示例：
定义一个接口：
public interface Log {
void debug();
}
定义两个实现类：
public class Log4j implements Log {
@Override
public void debug() {
System.out.println("==========log4j");
}
}
public class Logback implements Log {
@Override
public void debug() {
System.out.println("========logback");
}
}
配置文件配置：
代码：
cn.enjoy.javaspi.Log4j cn.enjoy.javaspi.Logback
测试获取代码：
public class MyTest {
public static void main(String[] args) {
//这个代码就会加载META-INF/services 下面的log接口的文件中的所有类
ServiceLoader all = ServiceLoader.load(Log.class);
Iterator iterator = all.iterator();
//这个地方需要挨个遍历去区分每一个实例的不同
while (iterator.hasNext()) {
Log next = iterator.next();
if(next instanceof Log4j) {
next.debug();
}
}
}
}
2）dubbospi代码示例：
定义接口一个：
//这个注解一定要
@SPI("spring")
public interface ActivateApi {
String todo(String param);
}
定义实现类N个：
import com.alibaba.dubbo.common.extension.Activate;
import com.alibaba.dubbo.common.extension.Adaptive;
@Adaptive
@Activate(order = 2,group = {"dubbo"})
public class DubboActivate implements ActivateApi {
@Override
public String todo(String param) {
return param;
}
}
@Activate(group = {"mybatis","mybatis1"})
public class MyBatisActivate implements ActivateApi {
@Override
public String todo(String param) {
return param;
}
}
@Activate(group = {"rabbitmq"})
public class RabbitmqActivate implements ActivateApi {
@Override
public String todo(String param) {
return param;
}
}
@Activate(group = {"rabbitmq"})
public class RabbitmqActivate1 implements ActivateApi {
@Override
public String todo(String param) {
return param;
}
}
@Activate(value = {"value1"},group = {"rabbitmq"})
public class RabbitmqActivate2 implements ActivateApi {
@Override
public String todo(String param) {
return param;
}
}
@Activate(group = {"spring"})
public class SpringActivate implements ActivateApi {
@Override
public String todo(String param) {
return param;
}
}
@Activate(order = 1,group = {"springcloud"})
public class SpringCloudActivate implements ActivateApi {
@Override
public String todo(String param) {
return param;
}
}
配置文件配置：
核心配置：
dubbo=cn.enjoy.dubbospi.DubboActivate mybatis=cn.enjoy.dubbospi.MyBatisActivate rabbitmq=cn.enjoy.dubbospi.RabbitmqActivate rabbitmq1=cn.enjoy.dubbospi.RabbitmqActivate1 rabbitmq2=cn.enjoy.dubbospi.RabbitmqActivate2 spring=cn.enjoy.dubbospi.SpringActivate springcloud=cn.enjoy.dubbospi.SpringCloudActivate
测试类：
import cn.nandao.dubbospi.ActivateApi;
import com.alibaba.dubbo.common.URL;
import com.alibaba.dubbo.common.extension.ExtensionLoader;
import com.alibaba.dubbo.registry.Registry;
import com.alibaba.dubbo.registry.RegistryFactory;
import com.alibaba.dubbo.rpc.Protocol;
import com.alibaba.dubbo.rpc.ProxyFactory;
import org.junit.Test;
import java.util.List;
public class SpiTest {
@Test
public void adaptive() {
//@Adaptive 有单独的api那实现了这个注解的实现类
ActivateApi adaptiveExtension = ExtensionLoader.getExtensionLoader(ActivateApi.class).getAdaptiveExtension();
System.out.println(adaptiveExtension.getClass());
}
@Test
public void test1() {
URL url = URL.valueOf("test://localhost/test");
url = url.addParameter("value1","gggg");
//只看分组，不看url中的参数
List rabbitmq = ExtensionLoader.getExtensionLoader(ActivateApi.class).getActivateExtension(url, new String[]{"spring"}, "rabbitmq");
System.out.println(rabbitmq.size());
for (ActivateApi activateApi : rabbitmq) {
System.out.println(activateApi.getClass());
}
}
@Test
public void defaultL() {
//寻找@SPI注解中配置的value值
System.out.println(ExtensionLoader.getExtensionLoader(ActivateApi.class).getDefaultExtension());
System.out.println(ExtensionLoader.getExtensionLoader(ActivateApi.class).getDefaultExtensionName());
//根据指定的name拿值
System.out.println(ExtensionLoader.getExtensionLoader(ActivateApi.class).getExtension("mybatis"));
System.out.println(ExtensionLoader.getExtensionLoader(ActivateApi.class).getSupportedExtensions());
}
@Test
public void protocol() {
// Protocol protocolproxy = ExtensionLoader.getExtensionLoader(Protocol.class).getAdaptiveExtension();
// System.out.println(protocolproxy);
System.out.println(ExtensionLoader.getExtensionLoader(Protocol.class).getAdaptiveExtension());
}
@Test
public void proxyFactory() {
System.out.println(ExtensionLoader.getExtensionLoader(ProxyFactory.class).getAdaptiveExtension());
}
@Test
public void override() {
RegistryFactory registryFactory = ExtensionLoader.getExtensionLoader(RegistryFactory.class).getAdaptiveExtension();
Registry registry = registryFactory.getRegistry(URL.valueOf("zookeeper://192.168.67.19:2184"));
registry.register(URL.valueOf("override://0.0.0.0/com.xiangxue.jack.service.UserService?category=configurators&dynamic=false&application=dubbo_provider&timeout=8900"));
}
@Test
public void decode() {
System.out.println(URL.decode("route%3A%2F%2F0.0.0.0%2Fcom.xiangxue.jack.service.UserService%3Fcategory%3Drouters%26dynamic%3Dfalse%26enabled%3Dtrue%26force%3Dfalse%26name%3DrouteTest%26priority%3D0%26router%3Dcondition%26rule%3Dmethod%2B%253D%2BqueryUser%2B%253D%253E%2Bprovider.cluster%2B%253D%2Bfailover%2B%2526%2Bprovider.host%2B%253D%2B192.168.90.126%2B%2526%2Bprovider.protocol%2B%253D%2Bdubbo%26runtime%3Dfalse"));
}
@Test
public void providerReg() {
RegistryFactory registryFactory = ExtensionLoader.getExtensionLoader(RegistryFactory.class).getAdaptiveExtension();
Registry registry = registryFactory.getRegistry(URL.valueOf("zookeeper://192.168.67.19:2184"));
registry.register(URL.valueOf("dubbo://192.168.2.23:20880/com.xiangxue.jack.service.UserService?anyhost=true&application=dubbo_provider&bean.name=ServiceBean:com.xiangxue.jack.service.UserService&connections=10&doKill.actives=10&doKill.executes=10&doKill.return=true&dubbo=2.0.2&generic=false&interface=com.xiangxue.jack.service.UserService&methods=doKill,queryUser&owner=world&pid=5704&revision=0.0.1-SNAPSHOT&side=provider×tamp=1626242405336&token=3d9492a1-c9ca-4bb4-a5de-a76a7a93684e"));
}
}
到此两者区别分享完毕，大家稍后一定多多测试，定会很快掌握。
