SpringCloud教程 | 二.Nacos服务配置与发现

素颜马尾好姑娘i 2021-09-23 07:22 506阅读 0赞

## 配置管理 ##

示例代码：[nacos-spring-boot-config-example][]

1.启动Nacos Server

2.pom文件添加依赖

<dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter</artifactId>
            </dependency>
    
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <optional>true</optional>
            </dependency>
            <dependency>
                <groupId>com.alibaba.boot</groupId>
                <artifactId>nacos-config-spring-boot-starter</artifactId>
                <version>0.2.1</version>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
        </dependencies>

3.application.properties

nacos.config.server-addr=127.0.0.1:8848

4.使用@NacosPropertySource加载dataId为example 的配置源，并开启自动更新：

@NacosPropertySource(dataId = "example",groupId = "own_test",autoRefreshed = true)
    @SpringBootApplication
    public class SpringcloudApplication {
        public static void main(String[] args) {
            SpringApplication.run(SpringcloudApplication.class, args);
        }
    }

5.通过Nacos的@NacosValue注解设置属性值

import com.alibaba.nacos.api.config.annotation.NacosValue;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;
    import org.springframework.web.bind.annotation.ResponseBody;
    
    @Controller
    @RequestMapping("config")
    public class ConfigController {
        @NacosValue(value = "${useLocalCache:false}", autoRefreshed = true)
        private boolean useLocalCache;
    
        @RequestMapping(value = "/get",method = RequestMethod.GET)
        @ResponseBody
        public boolean get() {
            return useLocalCache;
        }
    }

6.启动项目后在浏览器中请求`http://localhost:8080/config/get`，返回内容是 `false`。

7.通过调用 Nacos Open API向Nacos server发布配置：dataId 为example，内容为useLocalCache=true

POST请求 "http://127.0.0.1:8848/nacos/v1/cs/configs?dataId=example&group=DEFAULT_GROUP&content=useLocalCache=true"

8.再次访问 http://localhost:8080/config/get，此时返回内容为true，说明程序中的useLocalCache值已经被动态更新了。

## 服务发现 ##

示例代码：[nacos-spring-boot-discovery-example][]

1.启动Nachos Server服务

2.添加依赖

<dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter</artifactId>
            </dependency>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <optional>true</optional>
            </dependency>
            <dependency>
                <groupId>com.alibaba.boot</groupId>
                <artifactId>nacos-discovery-spring-boot-starter</artifactId>
                <version>0.2.1</version>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
        </dependencies>

3.application.properties

nacos.discovery.server-addr=127.0.0.1:8848

4.使用@NacosInjected注入Nacos的NamingService实例：

import com.alibaba.nacos.api.annotation.NacosInjected;
    import com.alibaba.nacos.api.exception.NacosException;
    import com.alibaba.nacos.api.naming.NamingService;
    import com.alibaba.nacos.api.naming.pojo.Instance;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.ResponseBody;
    import java.util.List;
    
    /**
     * Description:
     * 作者：gu.weidong(Marco)
     * date:2019/9/10
     * ProjectName:alibaba-nacos-discovery-server
     */
    @Controller
    @RequestMapping("discovery")
    public class DiscoveryController {
        @NacosInjected
        private NamingService namingService;
    
        @RequestMapping(value = "/get", method = RequestMethod.GET)
        @ResponseBody
        public List<Instance> get(@RequestParam String serviceName) throws NacosException {
            return namingService.getAllInstances(serviceName);
        }
    }

5.启动项目，浏览器请求http://localhost:8080/discovery/get?serviceName=example，此时返回为空JSON数组\[\]。

6.通过调用Nacos Open API向Nacos server注册一个名称为example服务

post请求 'http://127.0.0.1:8848/nacos/v1/ns/instance?serviceName=example&ip=127.0.0.1&port=8080'

7.再次访问 http://localhost:8080/discovery/get?serviceName=example，此时返回内容为：

[{
    	"instanceId": "127.0.0.1#8080#DEFAULT#DEFAULT_GROUP@@example",
    	"ip": "127.0.0.1",
    	"port": 8081,
    	"weight": 1.0,
    	"healthy": true,
    	"cluster": {
    		"serviceName": null,
    		"name": "",
    		"healthChecker": {
    			"type": "TCP"
    		},
    		"defaultPort": 80,
    		"defaultCheckPort": 80,
    		"useIPPort4Check": true,
    		"metadata": {}
    	},
    	"service": null,
    	"metadata": {}
    }]

[nacos-spring-boot-config-example]: https://github.com/nacos-group/nacos-examples/tree/master/nacos-spring-boot-example/nacos-spring-boot-config-example
[nacos-spring-boot-discovery-example]: https://github.com/nacos-group/nacos-examples/tree/master/nacos-spring-boot-example/nacos-spring-boot-discovery-example