Eureka-實現微服務的呼叫

尤拉兔發表於2019-03-19
微服務

1、Eureka的註冊中心

Maven依賴：

<?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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>euraka-server</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>euraka-server</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR1</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </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>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

啟動類：

//開啟Eureka註冊中心
@EnableEurekaServer
@SpringBootApplication
public class EurakaServerApplication {

    public static void main(String[] args) {
        SpringApplication.run(EurakaServerApplication.class, args);
    }

}

配置資訊： 

server.port=8761

eureka.instance.hostname=127.0.0.1
eureka.client.register-with-eureka=false
eureka.client.fetch-registry=false
eureka.client.service-url.defaultZone=http://${eureka.instance.hostname}:${server.port}/eureka/

eureka.server.enable-self-preservation=false
eureka.server.eviction-interval-timer-in-ms=5000

這裡我們Eureka註冊中心配置的地址時是： http://127.0.0.1:8761/eureka

 

2.服務提供者

Maven依賴：

<?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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>eureka-client</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>eureka-client</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR1</spring-cloud.version>
    </properties>

    <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </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>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

啟動類：

@EnableEurekaClient
@SpringBootApplication
public class EurekaClientApplication {

    public static void main(String[] args) {
        SpringApplication.run(EurekaClientApplication.class, args);
    }

}

配置檔案：

包含了註冊的服務名稱和註冊中心的地址

server.port=8762
spring.application.name=eureka-client1


eureka.client.service-url.defaultZone=http://127.0.0.1:8761/eureka/
# 拉取服務註冊資訊間隔（預設為30s）
eureka.client.registry-fetch-interval-seconds: 10 
# 關閉健康檢查
eureka.client.healthcheck.enabled=false
# 心跳時間，即服務續約間隔時間（預設為30s）
eureka.instance.lease-renewal-interval-in-seconds=5 
# 發呆時間，即服務續約到期時間（預設為90s）
eureka.instance.lease-expiration-duration-in-seconds=15

這裡我們的服務名稱是通過spring.application.name來配置的，也就是說服務名稱是eureka-client1

編寫簡單的服務：

@RestController
public class HelloController {


    //restful api方式
    @GetMapping("/hello/{name}")
    public String index(@PathVariable String name){
        return "hello!" + name;
    }

}

執行程式：

通過瀏覽器訪問http://127.0.0.1:8762/hello/yang：

說明服務正常訪問

 

通過瀏覽器訪問http://127.0.0.1:8761/，檢視Eureka註冊中心：

在Eureka註冊服務中服務提供者eureka-client1已經成功註冊上了。

 

3.使用RestTemplate實現服務消費

Maven配置檔案：

<?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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR1</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </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>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

 

啟動類：

@SpringBootApplication
//開啟Eureka客戶端
@EnableEurekaClient
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

}

配置檔案：

包含Eureka註冊服務名稱和Eureka註冊中心地址.

server.port=8764

spring.application.name=eureka-consumer1
#Eureka的註冊中心
eureka.client.serviceUrl.defaultZone=http://127.0.0.1:8761/eureka/

編寫服務

@Controller
/*載入RestTemplate的配置*/
@Configuration
public class TestController {

    @Bean
    //為RestTemplate開啟客戶端的負載均衡
    @LoadBalanced
    public RestTemplate getRestTemplate() {
        return new RestTemplate();
    }

    @GetMapping("/usertest/{name}")
    @ResponseBody
    public String router(@PathVariable String name) {
        RestTemplate tpl = getRestTemplate();
        //到註冊中心找服務並呼叫服務,eureka-client1就是服務提供者在註冊中心的名稱
        String result = tpl.getForObject("http://eureka-client1/hello/{name}", String.class,name);
        return result;
    }
    
}

啟動測試

http://127.0.0.1:8764/usertest/yang

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