During the interview, it is easy to be asked by the interviewer:
How to design an RPC framework?
You may not have been asked, maybe you are lucky, or maybe you are not at this level yet. Usually the monthly salary is more than 20k, and they will basically ask some design questions.
From the interviewer’s perspective: Asking this type of question is better than an eight-part essay, which involves many technical points. For example: knowledge about design patterns, communication protocols, dynamic agents, virtualization, thread pools, etc.
Okay, let’s not go too far, let’s start talking about today’s topic.
RPC is a Remote procedure call. Many people may not particularly understand these words. To put it simply:
It’s like calling a local The method is the same as calling the remote service.
For example, the following case: a user operates a service:
public interface UserService{
String findUserNameById(Integer userId);
}
@Service
public class UserServiceImpl implements UserService{
String findUserNameById(Integer userId){
//查数据或查缓存获取到用户名
return "田哥"
}
}Now a controller wants to call the findUserNameById method of UserServiceImpl to obtain the user name.
@RestController
public class UserController{
@Resource
private UserService userService;
@GetMapping("/test")
public String test(){
return userService.findUserNameById(1);
}
}Assuming that the three classes UserController, UserServiceImpl, and UserService are all in the same project, it is very simple for the controller to call the findUserNameById method.
However, if the controller is another project and wants to be called as above (subtle difference, the feeling is still the same), then we can use the RPC framework.
1. The interface UserService needs to be placed in a separate project, which we usually call an api project.
2. UserServiceImpl needs to be placed in a separate project, which we usually call the provider project.
3. Controller, through a web or other (consumer) project
4. Type the API into a jar package, and then reference it in both the consumer project and the provider project.
The RPC frameworks on the market, such as: Dubbo (Alibaba), Thrift (FaceBook), gRpc (Google), brpc (Baidu), etc., all focus on different aspects to solve the original purpose. Some want extreme perfection, some pursue extreme performance, and some prefer extreme simplicity.
Back to what we said earlierCalling remote services like calling local services, what technical support is needed?
UserService defined and no implementation class. Do you want to call a method of the interface? Then you can only create a proxy object. Why is a registration center needed? I have shared it before:
Meituan Interview: How to design a registration center?
根据上面的这些原理，田哥也搞了一个RPC框架，命名为mink（一个动物的名称）。
--mink ----mink-rpc rpc基本功能 ----mink-registry 服务注册与发现 ----mink-spring 集成SpringBoot
然后，我们把mink-spring打成jar包，服务发布和服务引用都把这个jar给依赖进去。
上面，我们创造了轮子，下面，我们就来看如何使用。
mink-demo就是一个Spring Boot项目，有三个module。
我们把mink-api打成jar包，共consumer和provider使用。
也就是我们在consumer和provider都引入：
<dependency>
<groupId>com.tian</groupId>
<artifactId>mink-api</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>下面，我们来看看provider端的代码：
<dependency> <groupId>com.tian</groupId> <artifactId>mink-spring</artifactId> <version>1.0-SNAPSHOT</version> </dependency> <dependency> <groupId>com.tian</groupId> <artifactId>mink-api</artifactId> <version>1.0-SNAPSHOT</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId> <version>2.5.4</version> </dependency>
我们的mink框架，只需要引入mink-spring依赖即可。
接着就是properties的配置：
mink.rpc.servicePort=20880 mink.rpc.registryType=0 mink.rpc.registryAddress=127.0.0.1:2181
再来看看具体服务实现类：
package com.tian.service;
import com.tian.annotation.MinkService;
/**
* @author tianwc 公众号：java后端技术全栈、面试专栏
* @version 1.0.0
* @description 用户服务
* @createTime 2022年08月23日 18:16
*/
@MinkService
public class UserServiceImpl implements UserService {
@Override
public String findUserNameByiD(Integer id) {
System.out.println("服务调用");
return "tian";
}
}这一步，我们只需要在实现类上加上注解@MinkService即可。
最后就是项目启动类：
@ComponentScan(basePackages = {"com.tian.service","com.tian"})
@SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}我们启动项目（注册中心用的是zookeeper）：
从日志中可以看出，我们的服务已经成功注册到注册中心了。
下面，我们来看看consumer端代码。
首先来看看依赖：
<dependency> <groupId>com.tian</groupId> <artifactId>mink-spring</artifactId> <version>1.0-SNAPSHOT</version> </dependency> <dependency> <groupId>com.tian</groupId> <artifactId>mink-api</artifactId> <version>1.0-SNAPSHOT</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId> <version>2.5.4</version> </dependency>org.springframework.boot spring-boot-starter-web 2.5.4
这依赖也很简单，没什么好说的。
再来看看properties配置项：
mink.rpc.registryType=0 mink.rpc.registryAddress=127.0.0.1:2181 server.port=8090
是不是也很简单？
再来看看我们的controller代码：
package com.tian.controller;
import com.tian.annotation.MinkReference;
import com.tian.service.UserService;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
/**
* @author tianwc 公众号：java后端技术全栈、面试专栏
* @version 1.0.0
* @description 消费端
* @createTime 2022年08月23日 23:08
*/
@RestController
public class UserController {
@MinkReference
private UserService userService;
@RequestMapping("/test")
public String test() {
return userService.findUserNameByiD(1);
}
}需要用到对应服务，只需要添加注解@MinkReference即可。
最后就是项目启动类，简单的不行。
@SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}启动日志：
访问：http://localhost:8090/test
成功！整个过程，非常轻松地集成mink框架并在业务代码中使用。
总结起来，其实就三步：
1、pom中添加依赖
2、properties文件中配置注册中心信息
3、使用的时候加上注解@MinkReference或 @MinkService即可
The above is the detailed content of The handwritten RPC framework is really not just for pretending to be 13!. For more information, please follow other related articles on the PHP Chinese website!
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