When multiple providers are registered at the register center, dynamically specifying one of the instances’ IP through RpcContext is enabled. Port does Dubbo invoke.
2.7.12 or above.Assume two registered providers at the register center are provided, which are 10.220.47.253:20880;10.220.47.253:20881; respectively.
// 10.220.47.253:20880
@Service(interfaceClass = TestService.class)
public class TestServiceImpl implements TestService {
@Override
public String sayHello(String name) {
return "Hello "+name+" i am provider1";
}
}
// 10.220.47.253:20881
@Service(interfaceClass = TestService.class)
public class TestServiceImpl implements TestService {
@Override
public String sayHello(String name) {
return "Hello "+name+" i am provider2";
}
}
@DubboReference introduces provider. Setting parameters = {“router”,“address”} specifies routing method.
For the instance that is going to be invoked, specify its IP, construct Address object with Port and set RpcContext key as “address”. Value is that object.
// require dependent class
import org.apache.dubbo.rpc.RpcContext;
import org.apache.dubbo.rpc.cluster.router.address.Address;
@RestController
public class TestServiceConsumer {
@DubboReference(interfaceClass = TestService.class,group = "dev",parameters = {"router","address"})
private TestService testService;
@GetMapping("/invokeByIpPortSpecified")
public String invokeByIp(){
try {
// create Address instance based on provider's ip port
Address address = new Address("10.220.47.253", 20880);
RpcContext.getContext().setObjectAttachment("address", address);
return testService.sayHello("Tom");
}catch (Throwable ex){
return ex.getMessage();
}
}
}
After running the code multiple times we can see that the same “Hello Tom i am provider1” is returned. In other words, we always route to the instance where port 20880 is located.
>curl http://localhost:8081/invokeByIpPortSpecified
>Hello Tom i am provider1