Eureka简介
Eureka采用的是Server/Client的模式进行设计。
Server扮演了服务注册中心的角色,为Client提供服务注册和发现的功能,维护着注册到自身的Client的相关信息,同时提供接口给Client获取到注册表中其他服务的信息。
Client将有关自己的服务的信息通过一定的方式登记到Server上,并在正常范围内维护自己信息的一致性,方便其他服务发现自己,同时可以通过Server获取到自己的依赖的其他服务信息,从而完成服务调用。
Eureka功能主要包括:
服务注册
、服务续约
、服务剔除
、服务下线
、获取注册表信息
、远程调用
等。
- 以下是Eureka几个角色的解释:
-
Eureka服务端
:负责服务注册、发现并管理每项服务的中心。 -
Eureka实例
:服务(如订单系统)部署多个服务器,每个服务器上提供的服务都是实例。 -
Eureka服务
:指提供特定服务功能的服务,例如:订单系统,同一服务可以提供多个实例; -
Eureka客户端
:主要向服务中心注册自己成为服务。但它既可以是服务提供者,也可以是消费者。它与Eureka实例感觉相似,但实际上意义不同。
-
Eureka项目创建
1、新建Maven项目
2、只保留Maven项目的依赖文件
pom.xml
文件作为后续创建的子模块依赖的父依赖文件
3、创建子模块(Eureka服务模块)
4、修改pom.xml
demo/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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example.demo</groupId>
<artifactId>demo</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>pom</packaging>
<modules>
<module>demo-eureka</module>
</modules>
<properties>
<java.version>1.8</java.version>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<spring-boot.version>2.6.13</spring-boot.version>
<spring-cloud.version>2021.0.5</spring-cloud.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<version>${spring-boot.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>${spring-boot.version}</version>
<executions>
<execution>
<id>repackage</id>
<goals>
<goal>repackage</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
demo/demo-eureka/pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<groupId>com.example.demo</groupId>
<artifactId>demo</artifactId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>demo-eureka</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>demo-eureka</name>
<description>demo-eureka</description>
</project>
5、创建并修改配置文件
demo/demo-eureka/src/main/resources/application.yml
server:
port: 8000
spring:
application:
name: demo-eureka
eureka:
instance:
hostname: 127.0.0.1
client:
register-with-eureka: false # 是否将自己注册到 Eureka-Server 中,默认的为 true
fetch-registry: false # 是否需要拉取服务信息,默认未true
service-url:
defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/ # 注册中心地址
6、添加Eureka注解
demo/demo-eureka/src/main/java/com/example/demo/demoeureka/DemoEurekaApplication.java
package com.example.demo.demoeureka;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
@EnableEurekaServer
@SpringBootApplication
public class DemoEurekaApplication {
public static void main(String[] args) {
SpringApplication.run(DemoEurekaApplication.class, args);
}
}
7、运行
8、创建其他服务
9、修改pom.xml
demo/pom.xml
<packaging>pom</packaging>
<modules>
<module>demo-eureka</module>
<module>demo-one</module>
<module>demo-two</module>
</modules>
demo/demo-one/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">
<parent>
<groupId>com.example.demo</groupId>
<artifactId>demo</artifactId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>demo-one</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>demo-one</name>
<description>demo-one</description>
</project>
demo/demo-two/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">
<parent>
<groupId>com.example.demo</groupId>
<artifactId>demo</artifactId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>demo-two</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>demo-two</name>
<description>demo-two</description>
</project>
10、创建并修改配置文件
把服务注册到Eureka中
demo/demo-one/src/main/resources/application.yml
server:
port: 8001
spring:
application:
name: demo-one
eureka:
client:
service-url:
defaultZone: http://127.0.0.1:8000/eureka/
demo/demo-two/src/main/resources/application.yml
server:
port: 8002
spring:
application:
name: demo-two
eureka:
client:
service-url:
defaultZone: http://127.0.0.1:8000/eureka/
11、添加Eureka注解
demo/demo-one/src/main/java/com/example/demo/demoone/DemoOneApplication.java
package com.example.demo.demoone;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
@EnableEurekaClient
@SpringBootApplication
public class DemoOneApplication {
public static void main(String[] args) {
SpringApplication.run(DemoOneApplication.class, args);
}
}
demo/demo-two/src/main/java/com/example/demo/demotwo/DemoTwoApplication.java
package com.example.demo.demotwo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
@EnableEurekaClient
@SpringBootApplication
public class DemoTwoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoTwoApplication.class, args);
}
}
12、添加项目服务
13、运行
14、访问404解决
开启监控服务配置demo/demo-one/src/main/resources/application.yml
开启监控服务配置demo/demo-two/src/main/resources/application.yml
management:
endpoints:
web:
exposure:
include: "*"
15、项目目录结构
搭建Eureka集群
应对服务挂了找不到服务的问题
1、准备
SwitchHosts
:用于修改 IP 和 域名 的映射https://github.com/oldj/SwitchHosts/releases
2. 创建 Eureka Server 模块
demo/pom.xml
<packaging>pom</packaging>
<modules>
<module>eureka-server-01</module>
<module>eureka-server-02</module>
<module>eureka-server-03</module>
<module>eureka-client-01</module>
</modules>
demo/eureka-server-01
、demo/eureka-server-02
、demo/eureka-server-03
- 启动类
-
demo/eureka-server-01/src/main/java/com/example/demo/eurekaserver01/EurekaServer01Application.java
package com.example.demo.eurekaserver01; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer; @EnableEurekaServer @SpringBootApplication public class EurekaServer01Application { public static void main(String[] args) { SpringApplication.run(EurekaServer01Application.class, args); } }
-
demo/eu¬reka-server-02/src/main/java/com/example/demo/eurekaserver01/EurekaServer02Application.java
package com.example.demo.eurekaserver02; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer; @EnableEurekaServer @SpringBootApplication public class EurekaServer02Application { public static void main(String[] args) { SpringApplication.run(EurekaServer02Application.class, args); } }
-
demo/eureka-server-03/src/main/java/com/example/demo/eurekaserver01/EurekaServer03Application.java
package com.example.demo.eurekaserver03; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer; @EnableEurekaServer @SpringBootApplication public class EurekaServer03Application { public static void main(String[] args) { SpringApplication.run(EurekaServer03Application.class, args); } }
-
- 配置项
-
demo/eureka-server-01/src/main/resources/application.yml
server: port: 8001 spring: application: name: eureka-server-01 eureka: instance: hostname: www.eureka-server-01.com client: register-with-eureka: false # 是否将自己注册到 Eureka-Server 中,默认的为 true fetch-registry: false # 是否需要拉取服务信息,默认未true service-url: defaultZone: http://www.eureka-server-02.com:8002/eureka/,http://www.eureka-server-03.com:8003/eureka/ # 注册中心地址
-
demo/eureka-server-02/src/main/resources/application.yml
server: port: 8002 spring: application: name: eureka-server-02 eureka: instance: hostname: www.eureka-server-02.com client: register-with-eureka: false # 是否将自己注册到 Eureka-Server 中,默认的为 true fetch-registry: false # 是否需要拉取服务信息,默认未true service-url: defaultZone: http://www.eureka-server-01.com:8001/eureka/,http://www.eureka-server-03.com:8003/eureka/ # 注册中心地址
-
demo/eureka-server-03/src/main/resources/application.yml
server: port: 8003 spring: application: name: eureka-server-03 eureka: instance: hostname: www.eureka-server-03.com client: register-with-eureka: false # 是否将自己注册到 Eureka-Server 中,默认的为 true fetch-registry: false # 是否需要拉取服务信息,默认未true service-url: defaultZone: http://www.eureka-server-01.com:8001/eureka/,http://www.eureka-server-02.com:8002/eureka/ # 注册中心地址
-
3、运行
4、创建 Eureka Client 模块并注册到Eureka服务中
- 启动类
-
demo/eureka-client-01/src/main/java/com/example/demo/eurekaclient01/EurekaClient01Application.java
package com.example.demo.eurekaclient01; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.netflix.eureka.EnableEurekaClient; @EnableEurekaClient @SpringBootApplication public class EurekaClient01Application { public static void main(String[] args) { SpringApplication.run(EurekaClient01Application.class, args); } }
-
- 配置项
-
demo/eureka-client-01/src/main/resources/application.yml
server: port: 8081 spring: application: name: eureka-client-01 eureka: instance: hostname: www.eureka-client-01.com instance-id: eureka-client-01 client: service-url: defaultZone: http://www.eureka-server-01.com:8001/eureka/,http://www.eureka-server-02.com:8002/eureka/,http://www.eureka-server-03.com:8003/eureka/ management: endpoints: web: exposure: include: "*"
-
5、运行
6、项目目录结构
网络请求获取数据
1、 创建项目
demo/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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example.demo</groupId>
<artifactId>demo</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>pom</packaging>
<modules>
<module>service-01</module>
<module>service-02</module>
</modules>
<properties>
<java.version>1.8</java.version>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<spring-boot.version>2.6.13</spring-boot.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<version>${spring-boot.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>${spring-boot.version}</version>
<executions>
<execution>
<id>repackage</id>
<goals>
<goal>repackage</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
demo/service-01/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">
<parent>
<groupId>com.example.demo</groupId>
<artifactId>demo</artifactId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>service-01</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>service-01</name>
<description>service-01</description>
</project>
demo/service-02/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">
<parent>
<groupId>com.example.demo</groupId>
<artifactId>demo</artifactId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>service-02</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>service-02</name>
<description>service-02</description>
</project>
demo/service-01/src/main/resources/application.yml
server:
port: 8001
demo/service-02/src/main/resources/application.yml
server:
port: 8002
2、 创建请求
demo/service-01/src/main/java/com/example/demo/service01/TestController.java
package com.example.demo.service01;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
@RestController
@RequestMapping
public class TestController {
private final RestTemplate restTemplate = new RestTemplate();
@GetMapping("msg")
public String msg() {
return "service-01 服务中请求 service-02";
}
@GetMapping("say")
public String say() {
String html = restTemplate.getForObject("https://www.example.com/", String.class);
String msg = restTemplate.getForObject("http://127.0.0.1:8002/msg", String.class);
return String.format("%s<h1 style=\"text-align: center;\">%s</h1>", html, msg);
}
}
demo/service-01/src/main/java/com/example/demo/service01/TestController.java
package com.example.demo.service02;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
@RestController
@RequestMapping
public class TestController {
private final RestTemplate restTemplate = new RestTemplate();
@GetMapping("msg")
public String msg() {
return "service-02 服务中请求 service-01";
}
@GetMapping("say")
public String say() {
String html = restTemplate.getForObject("https://www.example.com/", String.class);
String msg = restTemplate.getForObject("http://127.0.0.1:8001/msg", String.class);
return String.format("%s<h1 style=\"text-align: center;\">%s</h1>", html, msg);
}
}
3、 运行
4、 目录结构
利用Eureka实现服务间数据请求
1、 创建项目
demo/pom.xml
<packaging>pom</packaging>
<modules>
<module>eureka-server</module>
<module>service-01</module>
<module>service-02</module>
</modules>
2、 添加依赖
demo/pom.xml
<!-- 用于服务间请求的依赖 -->
<!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-starter-openfeign -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
3、 demo/eureka-server
demo/eureka-server/src/main/resources/application.yml
server:
port: 8001
spring:
application:
name: eureka-server
eureka:
instance:
hostname: www.eureka-server.com
client:
register-with-eureka: false # 是否将自己注册到 Eureka-Server 中,默认的为 true
fetch-registry: false # 是否需要拉取服务信息,默认未true
service-url:
defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/ # 注册中心地址
demo/eureka-server/src/main/java/com/example/demo/eurekaserver/EurekaServerApplication.java
package com.example.demo.eurekaserver;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
@EnableEurekaServer
@SpringBootApplication
public class EurekaServerApplication {
public static void main(String[] args) {
SpringApplication.run(EurekaServerApplication.class, args);
}
}
4、 demo/service-01
demo/service-01/src/main/resources/application.yml
server:
port: 8081
spring:
application:
name: service-01
eureka:
instance:
hostname: www.eureka-server.com
instance-id: service-01
client:
service-url:
defaultZone: http://www.eureka-server.com:8001/eureka/
management:
endpoints:
web:
exposure:
include: "*"
demo/service-01/src/main/java/com/example/demo/service01/Service01Application.java
package com.example.demo.service01;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.openfeign.EnableFeignClients;
@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients
public class Service01Application {
public static void main(String[] args) {
SpringApplication.run(Service01Application.class, args);
}
}
demo/service-01/src/main/java/com/example/demo/service01/api/IService02.java
package com.example.demo.service01.api;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
@FeignClient(value = "SERVICE-02")
public interface IService02 {
@GetMapping("/getMsg")
public String getMsg();
}
demo/service-01/src/main/java/com/example/demo/service01/Service01Controller.java
package com.example.demo.service01;
import com.example.demo.service01.api.IService02;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.annotation.Resource;
@RestController
@RequestMapping
public class Service01Controller {
@Resource
private IService02 service02;
@GetMapping("/say")
public String say(){
return service02.getMsg();
}
@GetMapping("getMsg")
public String getMsg() {
return "SERVICE-02 调用 SERVICE-01";
}
}
5、 demo/service-02
demo/service-02/src/main/resources/application.yml
server:
port: 8082
spring:
application:
name: service-02
eureka:
instance:
hostname: www.eureka-server.com
instance-id: service-02
client:
service-url:
defaultZone: http://www.eureka-server.com:8001/eureka/
management:
endpoints:
web:
exposure:
include: "*"
demo/service-02/src/main/java/com/example/demo/service02/Service02Application.java
package com.example.demo.service02;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.openfeign.EnableFeignClients;
@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients
public class Service02Application {
public static void main(String[] args) {
SpringApplication.run(Service02Application.class, args);
}
}
demo/service-02/src/main/java/com/example/demo/service02/api/IService01.java
package com.example.demo.service02.api;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
@FeignClient(value = "SERVICE-01")
public interface IService01 {
@GetMapping("/getMsg")
public String getMsg();
}
demo/service-02/src/main/java/com/example/demo/service02/Service02Controller.java
package com.example.demo.service02;
import com.example.demo.service02.api.IService01;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.annotation.Resource;
@RestController
@RequestMapping
public class Service02Controller {
@Resource
private IService01 service01;
@GetMapping("/say")
public String say(){
return service01.getMsg();
}
@GetMapping("getMsg")
public String getMsg() {
return "SERVICE-01 调用 SERVICE-02";
}
}
6、 运行
优先运行
EurekaServerApplication
启动类
文章来源:https://www.toymoban.com/news/detail-506410.html
7、 目录结构
文章来源地址https://www.toymoban.com/news/detail-506410.html
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