Rest学习环境搭建:服务消费者
pom.xml(springcloud-consumer-dept-80)
<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>springcloud</artifactId>
<groupId>com.kuang</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>springcloud-consumer-dept-80</artifactId>
<properties>
<maven.compiler.source>8</maven.compiler.source>
<maven.compiler.target>8</maven.compiler.target>
</properties>
<!--实体类+web-->
<dependencies>
<dependency>
<groupId>com.kuang</groupId>
<artifactId>springcloud-api</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
</dependency>
</dependencies>
</project>
config
ConfigBean.java
package com.kuang.springcloud.config;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;
@Configuration
public class ConfigBean { // @Configuration 相当于---spring 里面的applicationContext.xml
@Bean
public RestTemplate getRestTemplate(){
return new RestTemplate();
}
}
controller
DeptConsumerController.java
package com.kuang.springcloud.controller;
import com.kuang.springcloud.pojo.Dept;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
import java.util.List;
@RestController
public class DeptConsumerController {
//理解:消费者,不应该有service层 service是通过url去请求
//RestTemplate....有很多模板供我们直接调用 使用RestTemplate,需要注册到spring中
//String url,实体: Map, Class<T> responseType :请求的地址及响应的类型
@Autowired
private RestTemplate restTemplate; // RestTemplate 提供多种便捷访问远程http服务的方法,是简单的restful模板
//请求的地址是固定的所以把地址写死
private static final String REST_URL_PREFIX = "http://localhost:8001";
@RequestMapping("/consumer/dept/add")
public boolean add(Dept dept){
// REST_URL_PREFIX+"/dept/add",dept,Boolean.class 地址+ 具体的位置 传的对象 返回类型
return restTemplate.postForObject(REST_URL_PREFIX+"/dept/add",dept,Boolean.class);
}
@RequestMapping("/consumer/dept/get/{id}")
public Dept get(@PathVariable("id")Long id) {
return restTemplate.getForObject(REST_URL_PREFIX+"/dept/get/"+id, Dept.class);//去远程服务上拿
}
@RequestMapping("/consumer/dept/list")
public List<Dept> list(){
return restTemplate.getForObject(REST_URL_PREFIX+"/dept/list",List.class);
}
}
application.yml
server:
port: 80
测试
DeptConsumer_80.java
package com.kuang.springcloud;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class DeptConsumer_80 {
public static void main(String[] args){
SpringApplication.run(DeptConsumer_80.class,args);
}
}
目录:

注意:把提供方先启动自测一下 然后再启动消费者方
结果:
访问:localhost/consumer/dept/get/1

添加:localhost/consumer/dept/add?dname=233

5Eureka 服务注册与发现
5.1什么是Eureka
- Netflix在设计Eureka时,遵循的就是AP原则
- Eureka是Netflix的一个子模块,也是核心模块之一。Eureka是一个基于REST的服务,用于定位服务,以实现云端中间层服务发现和故障转移,服务注册与发现对于微服务来说是非常重要的,有了服务发现与注册,只需要使用服务的标识符,就可以访问到服务,而不需要修改服务调用的配置文件了,功能类似于Dubbo的注册。
5.2原理讲解
- Eureka的基本架构
- SpringCloud封装了NetFlix公司开发的Eureka模块来实现服务注册与发现(对比Zookeeper)
- Eureka采用了C-S的架构设计,EurekaServer作为服务注册功能的服务器,他是服务注册中心。
- 而系统中的其他微服务。使用Eureka的客户端连接到EurekaServer并维持心跳连接。这样系统的维护人员就可以通过EurekaServer来监控系统中各个微服务是否正常运行,SpringCloud的一些其他模块(比如Zuul)就可以通过EurekaServer来发现系统中的其他微服务,并执行相关的逻辑;
- Eureka包含两个组件:Eureka Server 和 Eureka Client
- Eureka Server 提供服务注册服务,各个节点启动后,会在EurekaServer中进行注册,这样Eureka Server 中的服务注册表中将会储存所有可用服务节点的信息,服务节点的信息可以在界面中直观的看到。
- Eureka Client是一个Java客户端,用于简化Eureka Server 的交互,客户端同时也具备一个内置的,使用轮询负载算法的负载均衡器。在应用启动后,将会向Eureka Server 发送心跳(默认周期为30秒)。如果Eureka Server 在多个心跳周期内没有接收到某个节点的心跳,Eureka Server 将会从服务注册表中把这个服务节点移除调(默认周期是90秒)。
- 三大角色
- Eureka Server :提供服务的注册与发现。(相当于zookeeper的客户端)
- Service Provider: 将自身服务注册到Eureka 中,从而使消费方能够找到。
- Service Consumer:服务消费方从Eureka 中获取注册服务列表,从而找到消费服务。
**在运行中会出各种各样的错,总的原因都是pom.xml父依赖里面的问题,所以该降级的要降级 **
父依赖pom.xml(springcloud)
<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.kuang</groupId>
<artifactId>springcloud</artifactId>
<version>1.0-SNAPSHOT</version>
<modules>
<module>springcloud-api</module>
<module>springcloud-provider-dept-8001</module>
<module>springcloud-consumer-dept-80</module>
<module>springcloud-eureka-7001</module>
<module>springboot-eureka1-7001</module>
</modules>
<packaging>pom</packaging>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
<junit.version>4.12</junit.version>
<log4j.version>1.2.17</log4j.version>
<lombok.version>1.16.18</lombok.version>
</properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-alibaba-dependencies</artifactId>
<version>0.2.0.RELEASE</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<!--springCloud的依赖-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Greenwich.SR1</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<!--SpringBoot-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<version>2.1.4.RELEASE</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<!--数据库-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.47</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.1.10</version>
</dependency>
<!--SpringBoot 启动器-->
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.2</version>
</dependency>
<!--日志测试~-->
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-core</artifactId>
<version>1.2.3</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>${junit.version}</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>${log4j.version}</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>${lombok.version}</version>
</dependency>
</dependencies>
</dependencyManagement>
</project>
pom.xml(springboot-eureka1-7001)
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>springcloud</artifactId>
<groupId>com.kuang</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>springboot-eureka1-7001</artifactId>
<!--导包~-->
<dependencies>
<!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-starter-eureka-server -->
<!--导入Eureka Server依赖-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka-server</artifactId>
<version>1.4.6.RELEASE</version>
</dependency>
<!--热部署工具-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
</dependency>
</dependencies>
</project>
application.yml
server:
port: 7001
# Eureka配置
eureka:
instance:
hostname: localhost # Eureka服务端的实例名称
client:
register-with-eureka: false # 是否向eureka注册自己 它是服务端就不用注册自己
fetch-registry: false # fetch-registry如果为false,则表示自己为注册中心
service-url:
defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/ # 监控页面
测试
EurekaServer_7001.java
package com.kuang.springcloud;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
//启动之后访问页面 http://localhost:7001/
@SpringBootApplication
@EnableEurekaServer// EnableEurekaServer服务端启动类,可以接受别人注册进来
public class EurekaServer_7001 {
public static void main(String[] args) {
SpringApplication.run(EurekaServer_7001.class,args);
}
}
测试结果:

Rureka:服务注册 信息配置 自我保护机制
springcloud-provider-dept-8001
在pom.xml(springcloud-provider-dept-8001)中导入依赖
<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>springcloud</artifactId>
<groupId>com.kuang</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>springcloud-provider-dept-8001</artifactId>
<properties>
<maven.compiler.source>8</maven.compiler.source>
<maven.compiler.target>8</maven.compiler.target>
</properties>
<dependencies>
<!-- Eureka的依赖-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
<version>1.4.6.RELEASE</version>
</dependency>
<dependency>
<groupId>com.kuang</groupId>
<artifactId>springcloud-api</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-core</artifactId>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-test</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jetty</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
</dependency>
</dependencies>
</project>
application.yml
server:
port: 8001
mybatis:
type-aliases-package: com.kuang.springcloud.pojo
config-location: classpath:mybatis/mybatis-config.xml
mapper-locations: classpath:mybatis/mapper/*.xml
spring:
application:
name: springcloud-provider-dept
datasource:
type: com.alibaba.druid.pool.DruidDataSource
driver-class-name: org.gjt.mm.mysql.Driver
url: jdbc:mysql://localhost:3306/db01?useUnicode=true&characterEncoding=utf-8
username: root
password: 123456
# Eureka的配置,服务注册到哪里
eureka:
client:
service-url:
defaultZone: http://localhost:7001/eureka
测试: 先启动7001 再启动8001
DeptProvider_8001.java
package com.kuang.springcloud;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
//启动类
@SpringBootApplication
@EnableEurekaClient//在服务启动后自动注册到Eureka中
public class DeptProvider_8001 {
public static void main(String[] args){
SpringApplication.run(DeptProvider_8001.class,args);
}
}
测试结果:

修改application.yml之后要全部重启
server:
port: 8001
mybatis:
type-aliases-package: com.kuang.springcloud.pojo
config-location: classpath:mybatis/mybatis-config.xml
mapper-locations: classpath:mybatis/mapper/*.xml
spring:
application:
name: springcloud-provider-dept
datasource:
type: com.alibaba.druid.pool.DruidDataSource
driver-class-name: org.gjt.mm.mysql.Driver
url: jdbc:mysql://localhost:3306/db01?useUnicode=true&characterEncoding=utf-8
username: root
password: 123456
# Eureka的配置,服务注册到哪里
eureka:
client:
service-url:
defaultZone: http://localhost:7001/eureka
instance:
instance-id: springcloud-provider-dept8001 # 修改eureka上的默认描述信息
结果:

修改application.yml
server:
port: 8001
mybatis:
type-aliases-package: com.kuang.springcloud.pojo
config-location: classpath:mybatis/mybatis-config.xml
mapper-locations: classpath:mybatis/mapper/*.xml
spring:
application:
name: springcloud-provider-dept
datasource:
type: com.alibaba.druid.pool.DruidDataSource
driver-class-name: org.gjt.mm.mysql.Driver
url: jdbc:mysql://localhost:3306/db01?useUnicode=true&characterEncoding=utf-8
username: root
password: 123456
# Eureka的配置,服务注册到哪里
eureka:
client:
service-url:
defaultZone: http://localhost:7001/eureka
instance:
instance-id: springcloud-provider-dept8001 # 修改eureka上的默认描述信息
# info 配置
info:
app.name: kuangshen-springcloud
company.name: blog.kuangstudy.com
结果页面:

点击跳转的页面:

6.Eureka的自我保护机制
自我保护机制:
一句话总结:某时刻某个微服务不可以用了,eureka不会立刻清理,依旧会对该服务的信息进行保存!
- 默认情况下,如果EurekaServer在一定时间内没有接收到某个微服务实例的心跳,EurekaServer将会注销该实例(默认90秒)。但是当网络分区故障发生时,微服务与Eureka之间无法正常通信。以上行为可能变得非常危险了。因为微服务本身其实是健康的,此时本不应该注销这个服务。Eureka通过自我保护机制来解决这个问题–当EurekaServer节点在短时间内丢失过多客户端时(可能发生了网络分区故障),那么这个节点就会进入自我保护模式。一旦进入该模式,EurekaServer就会保护服务注册表中的信息,不再删除服务注册表中的数据(也就是不会注销任何微服务)。当网络故障恢复后,该EurekaServer节点就会自动退出自我保护模式。
- 在自我保护模式中,EurekaServer会保护服务注册表中的信息,不再注销任何服务实例。当它收到的心跳数重新恢复到阈值以上时,该EurekaServer节点就会自动退出自我保护模式。它的设计哲学就是宁可保留错误的服务注册信息,也不盲目注销任何可能健康的服务实例。
- 综上,自我保护模式是一种应对网络异常的安全保护措施,它的架构哲学是宁可同时保留所有微服务(健康的微服务和不健康的微服务都会保留),也不盲目注销任何健康的微服务。使用自我保护模式,可以让Eureka集群更加的健壮和稳定。
- 在SpringCloud中,可以使用
eureka.server.enable-self-preservation = false禁用自我保护模式【不推荐关闭自我保护机制】
springcloud-provider-dept-8001
pom.xml(springcloud-provider-dept-8001)
<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>springcloud</artifactId>
<groupId>com.kuang</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>springcloud-provider-dept-8001</artifactId>
<properties>
<maven.compiler.source>8</maven.compiler.source>
<maven.compiler.target>8</maven.compiler.target>
</properties>
<dependencies>
<!-- Eureka的依赖-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
<version>1.4.6.RELEASE</version>
</dependency>
<!-- actuator完善监控信息-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>com.kuang</groupId>
<artifactId>springcloud-api</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-core</artifactId>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-test</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jetty</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
</dependency>
</dependencies>
</project>
DeptController.java
package com.kuang.springcloud.controller;
import com.kuang.springcloud.pojo.Dept;
import com.kuang.springcloud.service.DeptService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
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.RestController;
import java.util.List;
//Controller提供restful服务
@RestController //以json格式传输
public class DeptController {
@Autowired //这里就体现了controller调service层
private DeptService deptService;
//获取一些配置的信息,得到具体的微服务
@Autowired
private DiscoveryClient client;
@PostMapping("/dept/add")//添加请求一般以post提交 get不安全
public boolean addDept(Dept dept){
return deptService.addDept(dept);
}
@GetMapping("/dept/get/{id}")
public Dept get(@PathVariable("id") Long id){
return deptService.queryById(id);
}
@GetMapping ("/dept/list")
public List<Dept> queryAll(){
return deptService.queryAll();
}
//注册进来的微服务~ 获取一些消息~
@GetMapping("/dept/discovery")
public Object discovery(){
// 获取微服务列表的清单
List<String> services = client.getServices();
System.out.println("discovery=>services:" + services);
List<ServiceInstance> instances = client.getInstances("SPRINGCLOUD-PROVIDER-DEPT");
for (ServiceInstance instance : instances) {
System.out.println(
instance.getHost()+"\t"
+ instance.getPort()+"\t"
+ instance.getUri()+"\t"
+ instance.getServiceId()
);
}
return this.client;
}
}
测试:DeptProvider_8001.java
package com.kuang.springcloud;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
//启动类
@SpringBootApplication
@EnableEurekaClient//在服务启动后自动注册到Eureka中
@EnableDiscoveryClient //服务发现
public class DeptProvider_8001 {
public static void main(String[] args){
SpringApplication.run(DeptProvider_8001.class,args);
}
}
结果显示:

B站学习地址:【狂神说Java】SpringCloud最新教程IDEA版_哔哩哔哩 (゜-゜)つロ 干杯~-bilibili
本文介绍了如何在Spring Cloud中搭建Eureka服务注册与发现中心,包括EurekaServer的配置、服务提供者和服务消费者的设置。通过Eureka,实现了微服务之间的相互发现和健康检查,确保服务的高可用性。文中还提到了Eureka的自我保护机制,这是在网络异常时保持服务稳定的重要特性。
711

被折叠的 条评论
为什么被折叠?



