eurekaServer与eurekaClient关系
- Eureka Client：一个Java客户端，用于简化与 Eureka Server 的交互（通常就是微服务中的客户端和服务端）
- Eureka Server：提供服务注册和发现的能力（通常就是微服务中的注册中心）
一、搭建eureka server
1.1引入pom依赖
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency>
1.2配置application.properties
#eureka server端口
server.port=9000
spring.application.name=eurekaServer
#eureka配置
eureka.instance.hostname=localhost
#是否将自己注册到注册中心
eureka.client.register-with-eureka=false
#是否从eureka获取注册信息
eureka.client.fetch-registry=false
#暴露给Eureka Client的请求地址
eureka.client.service-url.defaultZone=http://localhost:9000/eureka/
#开发的时候配置这两项，正式上线保留
#关闭自我保护
eureka.server.enable-self-preservation=false
#剔除服务时间(毫秒)
eureka.server.eviction-interval-timer-in-ms=4000
1.3编写启动类
@SpringBootApplication
// 激活eurekaServer
@EnableEurekaServer
public class EurekaServerApplication {
public static void main(String[] args) {
SpringApplication.run(EurekaServerApplication.class, args);
}
}
启动EurekaServerApplication即搭建完成。
1.4测试地址
http://localhost:9000/eureka
2注册微服务到EurekaServer
2.1创建微服务提供者
pom文件
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<!-- 引入EurekaClient -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
</dependencies>
application.properties配置
server.port=9001
spring.application.name=product-service
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/shop?useUnicode=true&characterEncoding=utf-8
spring.datasource.username=root
spring.datasource.password=123456
spring.jpa.database=MySQL
spring.jpa.show-sql=true
spring.jpa.open-in-view=true
#配置eurekaClient
eureka.client.service-url.defaultZone=http://localhost:9000/eureka/
#使用IP地址注册
eureka.instance.prefer-ip-address=true
#在eurekaServer注册列表中以IP显示
eureka.instance.instance-id=${spring.cloud.client.ip-address}:${server.port}
#续约到期时间（每5秒发送一次心跳）
eureka.instance.lease-renewal-interval-in-seconds=5
eureka.instance.lease-expiration-duration-in-seconds=10
dao和serverice层省略，action层代码
@RestController
@RequestMapping("/product")
public class ProductController {
@Autowired
private ProductService productService;
@Value("${spring.cloud.client.ip-address}")
private String ip;
@Value("${server.port}")
private String port;
@RequestMapping(value="/{id}",method=RequestMethod.GET)
public Product findProductById(@PathVariable Long id){
Product product = productService.findById(id);
product.setProduct_name(ip+":"+port);
return product;
}
@RequestMapping(value="/save",method=RequestMethod.GET)
public String save(Product product){
productService.save(product);
return "保存成功";
}
启动类
@SpringBootApplication
@EntityScan("com.yan.product.entity")
//激活EurekaClient
//@EnableEurekaClient
@EnableDiscoveryClient
public class ProductApplication {
public static void main(String[] args) {
SpringApplication.run(ProductApplication.class, args);
}
}
2.1创建微服务消费者
pom文件
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<!-- 引入EurekaClient -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
</dependencies>
application.properties配置
server.port=9002
spring.application.name=order-service
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/shop?useUnicode=true&characterEncoding=utf-8
spring.datasource.username=root
spring.datasource.password=123456
spring.jpa.database=MySQL
spring.jpa.show-sql=true
spring.jpa.open-in-view=true
#配置eurekaClient
eureka.client.service-url.defaultZone=http://localhost:9000/eureka/
#使用IP地址注册
eureka.instance.prefer-ip-address=true
通过spring提供的RestTemplate发送http请求调用服务调用层代码
@RestController
@RequestMapping("/order")
public class OrderController {
@Autowired
private RestTemplate restTemplete;
@Autowired
private DiscoveryClient discoveryClient;
@RequestMapping(value="/findById/{id}")
public String findById(@PathVariable Long id){
Product product = null;
product = restTemplete.getForObject("http://product-service/product/"+id, Product.class);
return product.toString();
}
@RequestMapping(value="/save")
public String save(){
List<ServiceInstance> instances = discoveryClient.getInstances("product_service");
for (ServiceInstance serviceInstance : instances) {
System.out.println(serviceInstance.getHost());
System.out.println(serviceInstance.getPort());
}
// restTemplete.getForObject("http://localhost:9001/product/save?status=1", Product.class);
return "保存成功";
}
// @RequestMapping(value="/findById/{id}")
// public String findById(@PathVariable Long id){
// System.out.println(id);
// Product product = restTemplete.getForObject("http://localhost:9001/product/"+id, Product.class);
// return product.toString();
// }
}
启动类
@SpringBootApplication
@EntityScan("com.yan.order.entity")
@EnableDiscoveryClient
public class OrderApplication {
@Bean
//@LoadBalanced
public RestTemplate getRestTemplete(){
return new RestTemplate();
}
public static void main(String[] args) {
SpringApplication.run(OrderApplication.class, args);
}
}
至此，启动eureka server ,微服务提供者、消费者三个服务，在eureka server管理平台即可看到两个注册上去的微服务。
3EurekaServer的高可用
eureka server可以同时存在多个，多个服务之间需要相互注册。
application.properties配置文件
#eureka server端口
server.port=8000
spring.application.name=eurekaServer
#eureka配置
eureka.instance.hostname=localhost
#是否将自己注册到注册中心
eureka.client.register-with-eureka=true
#是否从eureka获取注册信息
eureka.client.fetch-registry=true
#暴露给Eureka Client的请求地址
eureka.client.service-url.defaultZone=http://localhost:8000/eureka/
#开发的时候配置这两项，正式上线保留
#关闭自我保护
eureka.server.enable-self-preservation=false
#剔除服务时间(毫秒)
eureka.server.eviction-interval-timer-in-ms=4000
微服务的提供者和消费者也需要同时注册到所有的eureka server上,多个注册服务之间用英文逗号隔开。
#配置eurekaClient
eureka.client.service-url.defaultZone=http://localhost:8000/eureka/,http://localhost:9000/eureka/
4服务注册与发现源码分析
https://www.cnblogs.com/trust-freedom/p/10310606.html
5 eureka注解原理
通过springboot加载外部配置类类似，主要是通过@ImportSelect注解实现。
1、定义一个需要使用的类User
2、建立一个配置
import org.springframework.context.annotation.Bean;
public class UserConfig {
@Bean
public User getUser(){
User user = new User();
user.setName("***");
user.setAge(23);
return user;
}
}
3、实现ImportSelector
import org.springframework.context.annotation.ImportSelector;
import org.springframework.core.type.AnnotationMetadata;
public class UserImportSeletor implements ImportSelector{
@Override
public String[] selectImports(AnnotationMetadata arg0) {
//获取配置类的名称
return new String[]{UserConfig.class.getName()};
}
}
4、创建一个注解
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import org.springframework.context.annotation.Import;
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Target(ElementType.TYPE)
@Import(UserImportSeletor.class)
public @interface EnableUserBean {
}
5、测试使用
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
@EnableUserBean
public class TestApplication {
public static void main(String[] args) {
AnnotationConfigApplicationContext ac = new AnnotationConfigApplicationContext(TestApplication.class);
User user = ac.getBean(User.class);
System.out.println(user);
ac.close();
}
}
来源：CSDN
作者：qq_37119960
链接：https://blog.csdn.net/qq_37119960/article/details/103465802