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关于intellij-idea:SpringClub03ribbon负载均衡和重试

jiezi

一、ribbon 服务消费者

ribbon 提供了负载平衡和重试性能, 它底层是应用 RestTemplate 进行 Rest api 调用

1.RestTemplate

RestTemplate 是 SpringBoot 提供的一个 Rest 近程调用工具
它的罕用办法:

  • getForObject() – 执行 get 申请
  • postForObject() – 执行 post 申请

之前的系统结构是浏览器间接拜访后盾服务

前面咱们通过一个 Demo 我的项目演示 Spring Cloud 近程调用

上面咱们先不应用 ribbon, 独自应用 RestTemplate 来执行近程调用

1.1 新建 sp06-ribbon 我的项目

1.2 批改 pom 文件

  • eureka-client 中曾经蕴含 ribbon 依赖
  • 须要增加 sp01-commons 依赖
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>cn.tedu</groupId>
    <artifactId>sp06-ribbon</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>sp06-ribbon</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Hoxton.RELEASE</spring-cloud.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>cn.tedu</groupId>
            <artifactId>sp01-commons</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>
    </dependencies>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

1.3 批改 application.yml

spring:
  application:
    name: ribbon
    
server:
  port: 3001
  
eureka:
  client:
    service-url:
      defaultZone: http://eureka1:2001/eureka, http://eureka2:2002/eureka

1.4 主程序

  • 创立 RestTemplate 实例
    RestTemplate 是用来调用其余微服务的工具类，封装了近程调用代码，提供了一组用于近程调用的模板办法，例如：getForObject()、postForObject() 等
package cn.tedu.sp06;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;
@EnableDiscoveryClient
@SpringBootApplication
public class Sp06RibbonApplication {
    // 创立 RestTemplate 实例，并存入 spring 容器
    @Bean
    public RestTemplate getRestTemplate() {return new RestTemplate();
    }
    public static void main(String[] args) {SpringApplication.run(Sp06RibbonApplication.class, args);
    }
}

1.5 创立 RibbonController 类

package com.tedu.sp06.controller;
import cn.tedu.sp01.pojo.Item;
import cn.tedu.sp01.pojo.Order;
import cn.tedu.sp01.pojo.User;
import cn.tedu.web.util.JsonResult;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.client.RestTemplate;
import java.util.List;
@RestController
@Slf4j
public class RibbonController {
    @Autowired
 private RestTemplate rt;
    @GetMapping("/item-service/{orderId}")
    public JsonResult<List<Item>> getItems(@PathVariable String orderId) {
        // 调用近程的商品服务，取得订单的商品列表
 // {1} - RestTemplate 本人定义的一种站位符格局
 return rt.getForObject("http://localhost:8001/{1}",
                JsonResult.class,
                orderId); // 用 orderId 填充占位符 {1} }
    @PostMapping("/item-service/decreaseNumber")
    public JsonResult<?> decreaseNumber(@RequestBody List<Item> items) {
        return rt.postForObject(
                "http://localhost:8001/decreaseNumber",
                items,
                JsonResult.class);
    }
    @GetMapping("/user-service/{userId}")
    public JsonResult<User> getUser(@PathVariable Integer userId) {return rt.getForObject("http://localhost:8101/{1}",
                JsonResult.class,
                userId);
    }
    @GetMapping("/user-service/{userId}/score") //    ?score=1000
 public JsonResult<?> addScore(@PathVariable Integer userId,
                                  @RequestParam Integer score) {return rt.getForObject("http://localhost:8101/{1}/score?score={2}",
                JsonResult.class,
                userId, score);
    }
    @GetMapping("/order-service/{orderId}")
    public JsonResult<Order> getOrder(@PathVariable String orderId) {return rt.getForObject("http://localhost:8201/{1}",
                JsonResult.class,
                orderId);
    }
    @GetMapping("/order-service/")
    public JsonResult<?> addOrder() {return rt.getForObject("http://localhost:8201/",JsonResult.class);
    }
}

1.6 启动服务，并拜访测试

http://eureka1:2001
http://localhost:3001/item-service/35
http://localhost:3001/item-service/decreaseNumber
应用 postman，POST 发送以下格局数据：
[{"id":1, "name":"abc", "number":23},{"id":2, "name":"def", "number":11}]
http://localhost:3001/user-service/7
http://localhost:3001/user-service/7/score?score=100
http://localhost:3001/order-service/123abc
http://localhost:3001/order-service/

2. ribbon 负载平衡和重试

2.1 Ribbon 负载平衡

2.1.1 增加 ribbon 依赖

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
</dependency>

2.1.2 RestTemplate 设置 @LoadBalanced

@LoadBalanced 负载平衡注解，会对 RestTemplate 实例进行封装，创立动静代理对象，并切入（AOP）负载平衡代码，把申请散发到集群中的服务器

package cn.tedu.sp06;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;
@EnableDiscoveryClient
@SpringBootApplication
public class Sp06RibbonApplication {
    @LoadBalanced // 负载平衡注解
    @Bean
    public RestTemplate getRestTemplate() {return new RestTemplate();
    }
    public static void main(String[] args) {SpringApplication.run(Sp06RibbonApplication.class, args);
    }
}

2.1.3 拜访门路设置为服务 id

package cn.tedu.sp06.controller;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
import cn.tedu.sp01.pojo.Item;
import cn.tedu.sp01.pojo.Order;
import cn.tedu.sp01.pojo.User;
import cn.tedu.web.util.JsonResult;
@RestController
public class RibbonController {
    @Autowired
    private RestTemplate rt;
    @GetMapping("/item-service/{orderId}")
@HystrixCommand(fallbackMethod = "getItemsFB")
public JsonResult<List<Item>> getItems(@PathVariable String orderId) {
    // 调用近程的商品服务，取得订单的商品列表
    //{1} - RestTemplate 本人定义的一种站位符格局
@PostMapping("/item-service/decreaseNumber")
public JsonResult<?> decreaseNumber(@RequestBody List<Item> items) {return rt.postForObject("http://item-service/decreaseNumber", items, JsonResult.class);
}
@GetMapping("/user-service/{userId}")
public JsonResult<User> getUser(@PathVariable Integer userId) {return rt.getForObject("http://user-service/{1}", JsonResult.class, userId);
}
@GetMapping("/user-service/{userId}/score") // ?score=1000
public JsonResult<?> addScore(@PathVariable Integer userId, @RequestParam Integer score) {return rt.getForObject("http://user-service/{1}/score?score={2}", JsonResult.class, userId, score);
}
@GetMapping("/order-service/{orderId}")
public JsonResult<Order> getOrder(@PathVariable String orderId) {return rt.getForObject("http://order-service/{1}", JsonResult.class, orderId);
}
@GetMapping("/order-service")
public JsonResult<?> addOrder() {return rt.getForObject("http://order-service", JsonResult.class);
}

2.1.4 拜访测试

  • 拜访测试，ribbon 会把申请散发到 8001 和 8002 两个服务端口上
    http://localhost:3001/item-service/34


2.2 ribbon 重试

2.2.1 增加 ribbon 依赖

<dependency>
    <groupId>org.springframework.retry</groupId>
    <artifactId>spring-retry</artifactId>
</dependency>

2.2.2 配置 application.yml

spring:
  application:
    name: ribbon   
server:
  port: 3001
#连贯 eureka
eureka:
  client:
    service-url:
      defaultZone: http://eureka1:2001/eureka, http://eureka2:2002/eureka
ribbon:
  #单台重试次数
 MaxAutoRetries: 1
  #更换服务器次数
 MaxAutoRetriesNextServer: 2

2.2.3 主程序设置 RestTemplate 的申请工厂的超时属性

package com.tedu.sp06;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.http.client.SimpleClientHttpRequestFactory;
import org.springframework.web.client.RestTemplate;
@SpringBootApplication
@EnableCircuitBreaker// 启用断路器
public class Sp06RibbonApplication {public static void main(String[] args) {SpringApplication.run(Sp06RibbonApplication.class, args);
   }
   // 创立 RestTemplate 实例，并存入 spring 容器
 @LoadBalanced// 负载平衡注解, 对 RestTemplate 进行封装, 加强 RestTemplate 的性能
 @Bean
 public RestTemplate getRestTemplate (){SimpleClientHttpRequestFactory f=new SimpleClientHttpRequestFactory();
      // 两个超时参数默认 -1，示意不启用
 f.setConnectTimeout(1000);
      f.setReadTimeout(1000);
      return new RestTemplate();}
}

2.2.4 ItemController 增加提早代码，以便测试 ribbon 的重试机制

package cn.tedu.sp02.item.controller;
import cn.tedu.sp01.pojo.Item;
import cn.tedu.sp01.service.ItemService;
import cn.tedu.web.util.JsonResult;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.*;
import java.util.List;
import java.util.Random;
@RestController
@Slf4j
public class ItemController {
    @Autowired
 private ItemService itemService;
    // 为了前面测试集群多台服务器，这里注入端口号
 @Value("${server.port}")
    private int port;
    @GetMapping("/{orderId}")
    public JsonResult<List<Item>> getItems(@PathVariable String orderId) throws InterruptedException {log.info("orderId="+orderId+", port="+port);
        // 增加随机提早代码
        if (Math.random()<0.9){
        // 随机产生 0 到 5000 的随机提早时长
            long t=new Random().nextInt(5000);
            log.info("提早:"+t);
            Thread.sleep(t);
        }
       //
        List<Item> items = itemService.getItems(orderId);
        return JsonResult.ok().msg("port="+port).data(items);
    }
    // 只解决 post 申请
 // @RequestBody 注解，残缺接管 post 申请协定体数据
 @PostMapping("/decreaseNumber")
    public JsonResult<?> decreaseNumber(@RequestBody List<Item> items) {itemService.decreaseNumber(items);
        return JsonResult.ok().msg("缩小商品库存胜利");
    }
}

2.2.5 测试 ribbon 重试机制

  • 通过 ribbon 拜访 item-service，当超时，ribbon 会重试申请集群中其余服务器
    http://localhost:3001/item-service/35


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