Spring Cloud Alibaba 教程 | Nacos 篇
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1、使用nacos做服务的注册和发现
1、父工程项目pom
<!--只做依赖管理，不引入依赖 -->
<dependencyManagement>
<dependencies>
<!--spring-boot-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<version>2.1.2.RELEASE</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<!-- spring-cloud -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Greenwich.SR2</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<!-- spring-cloud-alibaba -->
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-alibaba-dependencies</artifactId>
<version>2.1.0.RELEASE</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
2、nacos-provider 工程Pom文件
<dependencies>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.0</version>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<!--nacos注册中心服务治理-->
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>
</dependencies>
YAML文件配置
server:
port: 8081
servlet:
context-path: /nacos-provider
spring:
application:
name: nacos-provider
cloud:
nacos:
discovery:
server-addr: localhost:8848
服务提供类
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
@RequestMapping("/sayHello")
public class HelloController {
@RequestMapping("/test/{name}")
public String sayHello(@PathVariable("name") String name){
return "nihao! " + name;
}
}
3、nacos-consumer pom文件配置
<dependencies>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.0</version>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<!--注册中心服务治理-->
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>
</dependencies>
YAML配置
server:
port: 8082
spring:
application:
name: nacos-consumer
cloud:
nacos:
discovery:
server-addr: localhost:8848
消费类
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;
@SpringBootApplication
@EnableDiscoveryClient
public class NacosConsumerApplication {
public static void main(String[] args) {
SpringApplication.run(NacosConsumerApplication.class,args);
}
/**
* 创建RestTemplate并注入Spring容器
*/
@Bean
@LoadBalanced
public RestTemplate restTemplate(){
return new RestTemplate();
}
}
/**********************调用服务测试**************/
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;
@RestController
@RequestMapping("hello")
public class ConsumerController {
@Autowired
public RestTemplate restTemplate;
@RequestMapping("sayHi/{name}")
public String sayHello(@PathVariable("name") String name){
return restTemplate.getForObject("http://nacos-provider/nacos-provider/sayHello/test/" +name, String.class);
}
}
网页端测试：
http://localhost:8082/hello/sayHi/zhngsan
2、使用nacos做配置管理
微服务要拉取nacos中管理的配置，并且与本地的application.yml配置合并，才能完成项目启动。
但如果尚未读取application.yml，又如何得知nacos地址呢？
因此spring引入了一种新的配置文件：bootstrap.yaml文件，会在application.yml之前被读取，流程如下：
在nacos中新建配置
- 在需要抽取配置到nacos中的工程中引入nacos-config依赖配置：
<!--nacos配置管理依赖-->
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
</dependency>
-
添加bootstrap.yaml
spring: application: name: nacos-provider # 服务名称 profiles: active: dev #开发环境，这里是dev cloud: nacos: discovery: server-addr: 192.168.192.128:8848 config: server-addr: 192.168.192.128:8848 # Nacos地址 file-extension: yaml # 文件后缀名使用
${spring.application.name}-${spring.profiles.active}.${spring.cloud.nacos.config.file-extension}作为文件id，来读取配置。即nacos-provider-dev.yaml
3、读取nacos配置
@Value("${pattern.dateformat}")
private String dateFormater;
@RequestMapping("getConfig")
public String getConfig(){
return DateTimeFormatter.ofPattern(dateFormater).format(LocalDateTime.now());
}
2、1配置热更新
上面的步骤简单实现了读取nacos上的配置，还未实现配置的热更新。
要实现配置热更新，可以使用两种方式：
1、在@Value注入的变量所在类上添加注解@RefreshScope：
@RefreshScope
public class HelloController {
@Value("${pattern.dateformat}")
private String dateFormater;
}
2、使用@ConfigurationProperties注解的配置类代替@Value注解。
创建配置类：
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
@Component
@ConfigurationProperties(prefix = "pattern")
public class PaternProperties {
private String dateformat;
public String getDateformat() {
return dateformat;
}
public void setDateformat(String dateformat) {
this.dateformat = dateformat;
}
}
使用nacos配置
@Autowired
private PaternProperties paternProperties;
@RequestMapping("getConfig")
public String getConfig(){
return DateTimeFormatter.ofPattern(paternProperties.getDateformat()).format(LocalDateTime.now());
}
