GRPC Protobuf's Java class library integration and development guide
GRPC Protobuf's Java class library integration and development guide
Introduction:
GRPC (Google Remote Procedure Call) is a high -performance, open source communication framework that is implemented based on the Protocol Buffers (Protobuf).It allows developers to create distributed systems between different languages and provide a simple and easy -to -use interface definition language (IDL) to define services and messages.In this article, we will discuss how to integrate GRPC Protobuf in the Java application and explain the implementation process through some complete programming code and related configuration.
Step 1: Define .proto file
First, we need to define a .proto file to declare our service and message format.Suppose we are constructing a service called "UserService".First of all, we create a .proto file named "User.proto" and define our services and messages in it.
protobuf
syntax = "proto3";
package com.example;
service UserService {
rpc getUser(UserRequest) returns (UserResponse);
}
message UserRequest {
string userId = 1;
}
message UserResponse {
string username = 1;
int32 age = 2;
}
In the above example, we define a service called "UseRSERVICE", which contains an RPC method called "getuser".This method uses "userRequest" as the input parameter and returns "userResponse" as the output.
Step 2: Generate java class
After defining the .proto file, we need to use the Protobuf tool to generate the Java class.We can generate the Java class through the following command:
protoc --java_out=. user.proto
The command will generate the Java class corresponding to the .proto file in the current directory.
Step 3: Write the service implementation class
Next, we need to write a service implementation class that will implement the interface defined in the .proto file.In our example, the service implementation class will inherit the customized abstraction class and implement the abstract method.
package com.example;
public class UserServiceImpl extends UserServiceGrpc.UserServiceImplBase {
@Override
public void getUser(UserRequest request, StreamObserver<UserResponse> responseObserver) {
// Write the logic of obtaining user information here
UserResponse response = UserResponse.newBuilder()
.setUsername("John Doe")
.setAge(30)
.build();
responseObserver.onNext(response);
responseObserver.onCompleted();
}
}
In the above code, we implemented the "Getuser" method and wrote the logic of obtaining user information in it.We created a "userResponse" object and returned to the client through Responseobserver.
Step 4: Start GRPC server
Now, we need to write code to start the GRPC server and register our service implementation class.The following is a basic example:
package com.example;
import io.grpc.Server;
import io.grpc.ServerBuilder;
import java.io.IOException;
public class GRPCServer {
public static void main(String[] args) throws IOException, InterruptedException {
Server server = ServerBuilder.forPort(8080)
.addService(new UserServiceImpl())
.build();
server.start();
server.awaitTermination();
}
}
In the above example, we created a GRPC server and set the port to 8080.We also add our service implementation "UserserviceIMPL" to the service list of the server.Finally, we start the server and wait for the termination.
Step 5: Write client code
Finally, we need to write client code to call our services.The following is a basic example:
package com.example;
import io.grpc.ManagedChannel;
import io.grpc.ManagedChannelBuilder;
public class GRPCClient {
public static void main(String[] args) {
ManagedChannel channel = ManagedChannelBuilder.forAddress("localhost", 8080)
.usePlaintext()
.build();
UserServiceGrpc.UserServiceBlockingStub stub = UserServiceGrpc.newBlockingStub(channel);
UserRequest request = UserRequest.newBuilder()
.setUserId("123")
.build();
UserResponse response = stub.getUser(request);
System.out.println("Username: " + response.getUsername());
System.out.println("Age: " + response.getAge());
channel.shutdown();
}
}
In the above example, we created a connection with the server and used the Stub generated by "UserserViceGRPC" to call the remote method.We created a "userRequst" object and passed it as a parameter to the "Getuser" method.Finally, we printed the response of the server.
Summarize:
