本文介绍在http协议中，使用protobuf格式进行二进制数据通信。双方需设置http的header中ContentType为application/x-protobuf。

1、springboot下实现protobuf：

1）pom.xml

<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- protobuf -->
<dependency><groupId>com.google.protobuf</groupId><artifactId>protobuf-java</artifactId><version>3.11.0</version>
</dependency>
<dependency><groupId>com.google.protobuf</groupId><artifactId>protobuf-java-util</artifactId><version>3.11.0</version>
</dependency>
<dependency><groupId>com.googlecode.protobuf-java-format</groupId><artifactId>protobuf-java-format</artifactId><version>1.2</version>
</dependency>
<!-- 网络请求依赖 -->
<dependency><groupId>org.apache.httpcomponents</groupId><artifactId>httpclient</artifactId><version>4.5.2</version>
</dependency>
<dependency><groupId>org.apache.httpcomponents</groupId><artifactId>httpcore</artifactId><version>4.4</version>
</dependency>

2）user_login.proto

syntax = "proto3";
// 转成java后所在包
option java_package = "com.tencent.rating.audi_model_api.pb";
// 转成java后的类名
option java_outer_classname = "MessageUserLogin";
// 转java后生成一个java文件
option java_multiple_files = false;message MessageUserLoginRequest {string username = 1;string password = 2;
}
message MessageUserLoginResponse {string access_token = 1;string username = 2;
}

编译：

protoc --proto_path=/data/ --java_out=./ /data/user_login.proto

3）创建springboot工程，编写config：

@Configuration
public class WebConfig {@BeanProtobufHttpMessageConverter protobufHttpMessageConverter() {return new ProtobufHttpMessageConverter();}/*** protobuf 反序列化 可以不用配置*/
//    @Bean
//    RestTemplate restTemplate(ProtobufHttpMessageConverter protobufHttpMessageConverter) {
//        return new RestTemplate(Collections.singletonList(protobufHttpMessageConverter));
//    }
}

4）编写contorller：

import java.util.UUID;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import com.tencent.rating.audi_model_api.pb.MessageUserLogin;@Controller
public class PbTestController {	@RequestMapping(value = "/pbtest", produces = "application/x-protobuf")@ResponseBodypublic MessageUserLogin.MessageUserLoginResponse getPersonProto(@RequestBody MessageUserLogin.MessageUserLoginRequest request) {System.out.println("request:" + request.toString());MessageUserLogin.MessageUserLoginResponse.Builder builder = MessageUserLogin.MessageUserLoginResponse.newBuilder();builder.setAccessToken(UUID.randomUUID().toString()+"_res");builder.setUsername(request.getUsername()+"_res");return builder.build();}
}

然后启动sprinboot工程。监听8080端口

5）编写客户端请求：

public class PbTest {public static void main(String...strings) {try {String uri = "http://127.0.0.1:8080/clue/pbtest";MessageUserLogin.MessageUserLoginRequest.Builder builder = MessageUserLogin.MessageUserLoginRequest.newBuilder();builder.setUsername("tom");builder.setPassword("123456");HttpResponse response = doPost(uri, builder.build().toByteArray());MessageUserLogin.MessageUserLoginResponse messageUserLoginResponse = MessageUserLogin.MessageUserLoginResponse.parseFrom(response.getEntity().getContent());System.out.println("response:" + messageUserLoginResponse.toString());System.err.println(messageUserLoginResponse.getAccessToken());} catch (Exception e) {}}private static HttpResponse doPost(String uri, byte[] bytes) throws Exception {CloseableHttpResponse closeableHttpResponse = null;CloseableHttpClient httpclient = HttpClients.createDefault();try {HttpPost post = new HttpPost(uri);ByteArrayInputStream inputStream = new ByteArrayInputStream(bytes);InputStreamEntity inputStreamEntity = new InputStreamEntity(inputStream);post.setEntity(inputStreamEntity);post.addHeader("Content-Type", "application/x-protobuf");closeableHttpResponse = httpclient.execute(post);} catch (IOException e) {e.printStackTrace();} finally {// httpclient.close();}return closeableHttpResponse;}
}

2、servlet下实现protobuf： 

1）创建servlet项目，编写servlet代码：

import java.io.IOException;
import java.io.InputStream;
import java.util.UUID;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import servlet_test.pb.MessageUserLogin;
import servlet_test.pb.MessageUserLogin.MessageUserLoginRequest;
import servlet_test.pb.MessageUserLogin.MessageUserLoginResponse.Builder;@WebServlet(urlPatterns = {"/syncServlet2"})
public class SyncServlet2 extends HttpServlet {private static final long serialVersionUID = 1L;protected void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {//解析请求InputStream stream=request.getInputStream();MessageUserLoginRequest mlr = MessageUserLogin.MessageUserLoginRequest.parseFrom(stream);System.out.println(mlr.toString());//创建响应Builder newBuilder = MessageUserLogin.MessageUserLoginResponse.newBuilder();newBuilder.setAccessToken(UUID.randomUUID().toString()+"_res");newBuilder.setUsername(mlr.getUsername()+"_res");response.setCharacterEncoding("UTF-8");ServletOutputStream out = response.getOutputStream();out.write(newBuilder.build().toByteArray());out.flush();out.close();}
}

2）客户端测试：

同上。