eureka 启动多个，实现高可用
2，3，4 都向注册中心进行注册，每一个模块都应该使用多个，进行高可用
item和eureka实现高可用
实际情况下，需要在不同主机上进行部署，多台主机，端口号不用修改，但是在一台主机上测试，需要修改端口号
provider高可用配置
8001 端口
java -jar item.jar
java -jar item.jar --server.port=8002
访问两个端口测试
http://localhost:8001/35
http://localhost:8002/35
成功测试界面：
Eureka高可用配置
两个配置
主配置和profile同时存在会运行profile,profile是个性配置，主配置是通用配置
euraka1配置
eureka:
instance:
hostname: eureka1
client:
register-with-eureka: true
fetch-registry: true
euraka2配置
eureka:
instance:
hostname: eureka2
client:
register-with-eureka: true
fetch-registry: true
配置连接地址、
service-url.defaultZone: http://eureka2:2002/eureka
访问测试：
http://eureka1:2001/
http://eureka2:2002/
eureka客户端注册时，向两个服务器注册
修改以下微服务：
sp02-itemservice
sp03-userservice
sp04-orderservice
eureka:
client:
service-url:
defaultZone: http://eureka1:2001/eureka, http://eureka2:2002/eureka
当一个 eureka 服务宕机时，仍可以连接另一个 eureka 服务
测试连接：
06 功能演示项目—远程调用
06 调用02，03，04
02有集群，需要负载均衡调用 Ribbon容错
Ribbon 负载均衡和重试
负载均衡：
远程调用一个服务，在它的集群服务器之间来回调用，分散访问压力
重试：
一种容错方式，当调用远程服务器失败，可以自动进行重试调用
远程调用工具：RestTemplate
Spring 提供的远程调用工具，执行一个HTTP请求，并获得响应，一般获得的是JSON数据
底层有工具API，可将json转化为java对象
对Rest API调用过程做了高度封装，一步就可以完成发送请求，处理响应，json转换
getForObject(url,转化的类型，提交的参数)
postForObject(url,协议体数据，转化的类型)
不是springCloud工具是Spring提供的远程调用工具
Ribbon是对RestTemplate进行了封装，增强了RestTemplate的功能增强
Ribbon 案例测试
增加配置：
<dependency>
<groupId>cn.tedu</groupId>
<artifactId>sp01-commons</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>
RestTemplate
-http协议
-一次请求一次响应，之后断开连接，是一种短链接
-直接连接Web(tomcat)服务器
-调用的是Controller
Dubbo
-java序列化
-长连接
-连接Dubbo自己的端口（20880 默认）
-调用Service
-Dubbo效率高
1. 创建实例对象
1 在启动类中配置
2 添加一个配置类
2.创建Controller
package cn.tedu.sp06.controller;
import cn.tedu.sp01.pojo.Item;
import cn.tedu.web.util.JsonResult;
import lombok.extern.slf4j.Slf4j;
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.RestController;
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){
//调用远程服务,调用的是路径
return rt.getForObject("http://localhost:8001/{1}}", JsonResult.class,orderId);
}
}
访问测试：
调用远程的user
@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")
public JsonResult<?> addScore(@PathVariable Integer userId,Integer score){
return rt.getForObject("http://localhost:8101/{1}/score?score={2}",
JsonResult.class,userId,score);
}
调用远程的订单
@GetMapping("/order-service/")
public JsonResult<?> addOrder(String orderId){
return rt.getForObject("http://localhost:8201/", JsonResult.class);
}
@GetMapping("/order-service/{orderId}")
public JsonResult<Order> getOrder(@PathVariable String orderId){
return rt.getForObject("http://localhost:8201/{1}", JsonResult.class,orderId);
}
启动服务
测试eureka:
http://localhost:3001/user-service/7/score?score=100
http://localhost:3001/order-service/123abc
ribbon 重试
pom.xml 添加 spring-retry 依赖
复制代码到 pom.xml
<dependency>
<groupId>org.springframework.retry</groupId>
<artifactId>spring-retry</artifactId>
</dependency>
yml
spring:
application:
name: ribbon
server:
port: 3001
eureka:
client:
service-url:
defaultZone: http://eureka1:2001/eureka, http://eureka2:2002/eureka
ribbon:
MaxAutoRetriesNextServer: 2
MaxAutoRetries: 1
OkToRetryOnAllOperations: true
ConnectionTimeout
ReadTimeout
OkToRetryOnAllOperations=true
默认只对GET请求重试, 当设置为true时, 对POST等所有类型请求都重试
MaxAutoRetriesNextServer
更换实例的次数
MaxAutoRetries
当前实例重试次数，尝试失败会更换下一个实例
主程序设置 RestTemplate 的请求工厂的超时属性
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.http.client.SimpleClientHttpRequestFactory;
import org.springframework.web.client.RestTemplate;
@EnableDiscoveryClient
@SpringBootApplication
public class Sp06RibbonApplication {
@LoadBalanced
@Bean
public RestTemplate getRestTemplate() {
SimpleClientHttpRequestFactory f = new SimpleClientHttpRequestFactory();
f.setConnectTimeout(1000);
f.setReadTimeout(1000);
return new RestTemplate(f);
//RestTemplate 中默认的 Factory 实例中，两个超时属性默认是 -1，
//未启用超时，也不会触发重试
//return new RestTemplate();
}
public static void main(String[] args) {
SpringApplication.run(Sp06RibbonApplication.class, args);
}
}
item-service 的 ItemController 添加延迟代码，以便测试 ribbon 的重试机制
package cn.tedu.sp02.item.controller;
import java.util.List;
import java.util.Random;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
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 cn.tedu.sp01.pojo.Item;
import cn.tedu.sp01.service.ItemService;
import cn.tedu.web.util.JsonResult;
import lombok.extern.slf4j.Slf4j;
@Slf4j
@RestController
public class ItemController {
@Autowired
private ItemService itemService;
@Value("${server.port}")
private int port;
@GetMapping("/{orderId}")
public JsonResult<List<Item>> getItems(@PathVariable String orderId) throws Exception {
log.info("server.port="+port+", orderId="+orderId);
///--设置随机延迟
if(Math.random()<0.6) {
long t = new Random().nextInt(5000);
log.info("item-service-"+port+" - 暂停 "+t);
Thread.sleep(t);
}
///~~
List<Item> items = itemService.getItems(orderId);
return JsonResult.ok(items).msg("port="+port);
}
@PostMapping("/decreaseNumber")
public JsonResult decreaseNumber(@RequestBody List<Item> items) {
itemService.decreaseNumbers(items);
return JsonResult.ok();
}
}
访问，测试 ribbon 重试机制
通过 ribbon 访问 item-service，当超时，ribbon 会重试请求集群中其他服务器
http://localhost:3001/item-service/35
ribbon的重试机制，在 feign 和 zuul 中进一步进行了封装，后续可以使用feign或zuul的重试机制
Hystrix 断路器
微服务宕机时，ribbon 无法转发请求
复制 sp06-ribbon 项目，命名为sp07-hystrix
选择 sp06-ribbon 项目，ctrl-c，ctrl-v，复制为sp07-hystrix
关闭 sp06-ribbon 项目，后续测试使用 sp07-hystrix 项目
修改 pom.xml
添加 hystrix 起步依赖
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
</dependency>
修改 application.yml
spring:
application:
name: hystrix
server:
port: 3001
eureka:
client:
service-url:
defaultZone: http://eureka1:2001/eureka, http://eureka2:2002/eureka
ribbon:
MaxAutoRetries: 1
MaxAutoRetriesNextServer: 2
OkToRetryOnAllOperations: true
主程序添加 @EnableCircuitBreaker 启用 hystrix 断路器
启动断路器，断路器提供两个核心功能：
降级，超时、出错、不可到达时，对服务降级，返回错误信息或者是缓存数据
熔断，当服务压力过大，错误比例过多时，熔断所有请求，所有请求直接降级
可以使用 @SpringCloudApplication 注解代替三个注解
package cn.tedu.sp06;
import org.springframework.boot.SpringApplication;
import org.springframework.cloud.client.SpringCloudApplication;
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;
//@EnableCircuitBreaker
//@EnableDiscoveryClient
//@SpringBootApplication
@SpringCloudApplication
public class Sp06RibbonApplication {
@LoadBalanced
@Bean
public RestTemplate getRestTemplate() {
SimpleClientHttpRequestFactory f = new SimpleClientHttpRequestFactory();
f.setConnectTimeout(1000);
f.setReadTimeout(1000);
return new RestTemplate(f);
//RestTemplate 中默认的 Factory 实例中，两个超时属性默认是 -1，
//未启用超时，也不会触发重试
//return new RestTemplate();
}
public static void main(String[] args) {
SpringApplication.run(Sp06RibbonApplication.class, args);
}
}
RibbonController 中添加降级方法
为每个方法添加降级方法，例如 getItems() 添加降级方法 getItemsFB()
添加 @HystrixCommand 注解，指定降级方法名
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 com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
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") //指定降级方法的方法名
public JsonResult<List<Item>> getItems(@PathVariable String orderId) {
return rt.getForObject("http://item-service/{1}", JsonResult.class, orderId);
}
@PostMapping("/item-service/decreaseNumber")
@HystrixCommand(fallbackMethod = "decreaseNumberFB")
public JsonResult decreaseNumber(@RequestBody List<Item> items) {
return rt.postForObject("http://item-service/decreaseNumber", items, JsonResult.class);
}
/
@GetMapping("/user-service/{userId}")
@HystrixCommand(fallbackMethod = "getUserFB")
public JsonResult<User> getUser(@PathVariable Integer userId) {
return rt.getForObject("http://user-service/{1}", JsonResult.class, userId);
}
@GetMapping("/user-service/{userId}/score")
@HystrixCommand(fallbackMethod = "addScoreFB")
public JsonResult addScore(@PathVariable Integer userId, Integer score) {
return rt.getForObject("http://user-service/{1}/score?score={2}", JsonResult.class, userId, score);
}
/
@GetMapping("/order-service/{orderId}")
@HystrixCommand(fallbackMethod = "getOrderFB")
public JsonResult<Order> getOrder(@PathVariable String orderId) {
return rt.getForObject("http://order-service/{1}", JsonResult.class, orderId);
}
@GetMapping("/order-service")
@HystrixCommand(fallbackMethod = "addOrderFB")
public JsonResult addOrder() {
return rt.getForObject("http://order-service/", JsonResult.class);
}
/
//降级方法的参数和返回值，需要和原始方法一致，方法名任意
public JsonResult<List<Item>> getItemsFB(String orderId) {
return JsonResult.err("获取订单商品列表失败");
}
public JsonResult decreaseNumberFB(List<Item> items) {
return JsonResult.err("更新商品库存失败");
}
public JsonResult<User> getUserFB(Integer userId) {
return JsonResult.err("获取用户信息失败");
}
public JsonResult addScoreFB(Integer userId, Integer score) {
return JsonResult.err("增加用户积分失败");
}
public JsonResult<Order> getOrderFB(String orderId) {
return JsonResult.err("获取订单失败");
}
public JsonResult addOrderFB() {
return JsonResult.err("添加订单失败");
}
}
hystrix 超时设置
hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds
hystrix等待超时后, 会执行降级代码, 快速向客户端返回降级结果, 默认超时时间是1000毫秒
为了测试 hystrix 降级，我们把 hystrix 等待超时设置得非常小（500毫秒）
此设置一般应大于 ribbon 的重试超时时长，例如 10 秒
spring:
application:
name: hystrix
server:
port: 3001
eureka:
client:
service-url:
defaultZone: http://eureka1:2001/eureka, http://eureka2:2002/eureka
ribbon:
MaxAutoRetriesNextServer: 2
MaxAutoRetries: 1
OkToRetryOnAllOperations: true
hystrix:
command:
default:
execution:
isolation:
thread:
timeoutInMilliseconds: 500
启动项目进行测试
通过 hystrix 服务，访问可能超时失败的 item-service
http://localhost:3001/item-service/35
通过 hystrix 服务，访问未启动的 user-service
http://localhost:3001/user-service/7
可以看到，如果 item-service 请求超时，hystrix 会立即执行降级方法
访问 user-service，由于该服务未启动，hystrix也会立即执行降级方法
hystrix dashboard 断路器仪表盘
hystrix 对请求的降级和熔断，可以产生监控信息，hystrix dashboard可以实时的进行监控
sp07-hystrix 项目添加 actuator，并暴露 hystrix 监控端点
actuator 是 spring boot 提供的服务监控工具，提供了各种监控信息的监控端点
management.endpoints.web.exposure.include 配置选项，
可以指定端点名，来暴露监控端点
如果要暴露所有端点，可以用 “*”
pom.xml 添加 actuator 依赖
右键点击项目或pom.xml, 编辑起步依赖, 添加 actuator 依赖
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
调整 application.yml 配置，并暴露 hystrix.stream 监控端点
spring:
application:
name: hystrix
server:
port: 3001
eureka:
client:
service-url:
defaultZone: http://eureka1:2001/eureka, http://eureka2:2002/eureka
ribbon:
MaxAutoRetriesNextServer: 1
MaxAutoRetries: 1
OkToRetryOnAllOperations: true
hystrix:
command:
default:
execution:
isolation:
thread:
timeoutInMilliseconds: 500
management:
endpoints:
web:
exposure:
include: hystrix.stream
访问 actuator 路径，查看监控端点
http://localhost:3001/actuator
Hystrix dashboard 仪表盘
新建 sp08-hystrix-dashboard 项目
pom.xml
<?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>sp08-hystrix-dashboard</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>sp08-hystrix-dashboard</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.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-hystrix-dashboard</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>
</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>
application.yml
spring:
application:
name: hystrix-dashboard
server:
port: 4001
eureka:
client:
service-url:
defaultZone: http://eureka1:2001/eureka, http://eureka2:2002/eureka
hystrix:
dashboard:
proxy-stream-allow-list: localhost
主程序添加 @EnableHystrixDashboard 和 @EnableDiscoveryClient
package cn.tedu.sp08;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.hystrix.dashboard.EnableHystrixDashboard;
@EnableDiscoveryClient
@EnableHystrixDashboard
@SpringBootApplication
public class Sp08HystrixDashboardApplication {
public static void main(String[] args) {
SpringApplication.run(Sp08HystrixDashboardApplication.class, args);
}
}
启动，并访问测试
访问 hystrix dashboard
http://localhost:4001/hystrix
填入 hystrix 的监控端点，开启监控
http://localhost:3001/actuator/hystrix.stream
通过 hystrix 访问服务多次，观察监控信息
http://localhost:3001/item-service/35
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/