Dubbo-spi-demo与Adaptive使用

建立API模块-dubbo-spi-demo-api

• api添加依赖

    <dependencies>
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo</artifactId>
            <version>2.7.5</version>
        </dependency>
    </dependencies>

• 建立Service-添加spi注解

@SPI
public interface HelloService {

    String  sayHello();
}

• 建立实现-依赖上面的模块
  

public class DogHelloServiceImpl implements HelloService {
    @Override
    public String sayHello() {
        return "hello dog";
    }
}
public class HumanHelloServiceImpl implements HelloService {

    @Override
    public String sayHello() {
        return "hello Human";
    }
}

• 在resources目录下建立META-INF/dubbo目录
  
  文件名就是接口名-内容key=value

dog=com.liu.service.impl.DogHelloServiceImpl
human=com.liu.service.impl.HumanHelloServiceImpl

• 测试

 ExtensionLoader<HelloService> extensionLoader = ExtensionLoader.getExtensionLoader(HelloService.class);


        Set<String> supportedExtensions = extensionLoader.getSupportedExtensions();

        supportedExtensions.forEach(s->{
            System.out.println(extensionLoader.getExtension(s).sayHello());
        });

hello dog
hello Human

• 添加spi默认-在接口上

@SPI("dog")
public interface HelloService {

    String  sayHello();
}

• 测试修改

    public static void main(String[] args) {

        ExtensionLoader<HelloService> extensionLoader = ExtensionLoader.getExtensionLoader(HelloService.class);


        Set<String> supportedExtensions = extensionLoader.getSupportedExtensions();

        supportedExtensions.forEach(s->{
            System.out.println(extensionLoader.getExtension(s).sayHello());
        });

        System.out.println("===============");
        HelloService defaultExtension = extensionLoader.getDefaultExtension();
        System.out.println(defaultExtension.sayHello());

    }
}

hello dog
hello Human
===============
hello dog

getDefaultExtension可以获取默认配置的是哪个接口实现

• JDK 标准的 SPI 会一次性实例化扩展点所有实现，如果有扩展实现初始化很耗时，但如果没用上也加
  载，会很浪费资源
• 如果有扩展点加载失败，则所有扩展点无法使用

Adaptive

@SPI("dog")
public interface HelloService {

    String  sayHello();

    @Adaptive
    String sayHello(URL url);
}

public class DogHelloServiceImpl implements HelloService {
    @Override
    public String sayHello() {
        return "hello dog";
    }

    @Override
    public String sayHello(URL url) {
        return "hello dog : "+url;
    }
}

public class HumanHelloServiceImpl implements HelloService {

    @Override
    public String sayHello() {
        return "hello Human";
    }

    @Override
    public String sayHello(URL url) {
        return "hello Human   "+url;
    }
}

public class AdaptiveMain {
    public static void main(String[] args) {
        /**
         * 这里注意?后面
         * hello.service=HelloService
         * =后面就是在配置文件中的key
         */
        URL   url  = URL.valueOf("test://localhost/hello?hello.service=human");
        ExtensionLoader<HelloService> extensionLoader = ExtensionLoader.getExtensionLoader(HelloService.class);

        HelloService helloService = extensionLoader.getAdaptiveExtension();

        System.out.println(helloService.sayHello(url));
    }
}

hello Human test://localhost/hello?hello.service=human

如果不写就调用@SPI注解配置的，

public class AdaptiveMain {
    public static void main(String[] args) {
        /**
         * 这里注意?后面
         * hello.service=HelloService
         * =后面就是在配置文件中的key
         * ?hello.service=human
         */
        URL   url  = URL.valueOf("test://localhost/hello");
        ExtensionLoader<HelloService> extensionLoader = ExtensionLoader.getExtensionLoader(HelloService.class);

        HelloService helloService = extensionLoader.getAdaptiveExtension();

        System.out.println(helloService.sayHello(url));
    }
}

hello dog : test://localhost/hello

最后

以上就是坚强白猫为你收集整理的Dubbo-spi-demo与Adaptive使用的全部内容，希望文章能够帮你解决Dubbo-spi-demo与Adaptive使用所遇到的程序开发问题。

如果觉得靠谱客网站的内容还不错，欢迎将靠谱客网站推荐给程序员好友。