1. 什麼是Spring Cloud?
Spring提供了一系列工具,可以幫助開發人員迅速搭建分佈式系統中的公共組件(比如:配置管理,服務發現,斷路器,智能路由,微代理,控制總線,一次性令牌,全局鎖,主節點選舉, 分佈式session, 集羣狀態)。協調分佈式環境中各個系統,爲各類服務提供模板性配置。使用Spring Cloud, 開發人員可以搭建實現了這些樣板的應用,並且在任何分佈式環境下都能工作得非常好,小到筆記本電腦, 大到數據中心和雲平臺。
Spring Cloud官網的定義比較抽象,我們可以從簡單的東西開始。Spring Cloud是基於Spring Boot的, 最適合用於管理Spring Boot創建的各個微服務應用。要管理分佈式環境下的各個Spring Boot微服務,必然存在服務的註冊問題。所以我們先從服務的註冊談起。既然是註冊,必然有個管理註冊中心的服務器,各個在Spring Cloud管理下的Spring Boot應用就是需要註冊的client
Spring Cloud使用erureka server, 然後所有需要訪問配置文件的應用都作爲一個erureka client註冊上去。eureka是一個高可用的組件,它沒有後端緩存,每一個實例註冊之後需要向註冊中心發送心跳,在默認情況下erureka server也是一個eureka client ,必須要指定一個 server。
2.項目採用maven聚合工程 用spring boot 搭建 spring cloud的微服務 模塊式開發:
2.1創建聚合工程的父模塊
2.2設置父模塊的POM文件(沒有管理版本):
<?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">
<modelVersion>4.0.0</modelVersion>
<groupId>com.guo</groupId>
<artifactId>springCloud-parent</artifactId>
<version>1.0-SNAPSHOT</version>
</project>
3.創建Eureka Server
3.1創建 Eureka server
3.2 引入子模塊pom。
<?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">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.3.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.guo</groupId>
<artifactId>eureka-server</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>eureka-server</name>
<packaging>war</packaging>
<description>Demo project for Spring Boot</description>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
<spring-cloud.version>Finchley.RELEASE</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>
<!--eureka server安全認證 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
子模塊管理到父pom中(可以省略)
<!-- 子模塊 -->
<modules>
<module>eureka-server</module>
</modules>
3.3 在application.yml中加入配置
application.yml
spring:
application:
name: boot-eureka
#不想讓所有人都能訪問到eurekaserver的界面,可以加上權限認證
security:
user:
name: admin
password: 123456
profiles:
#指向開發環境的yml文件
active: dev
application-dev.yml
server:
port: 8081
eureka:
instance:
hostname: localhost
server: #配置屬性,但由於 Eureka 自我保護模式以及心跳週期長的原因,經常會遇到 Eureka Server 不剔除已關停的節點的問題
enable-self-preservation: false
eviction-interval-timer-in-ms: 5000
peer-eureka-nodes-update-interval-ms: 1000
wait-time-in-ms-when-sync-empty: 0
# 不向註冊中心註冊自己
client:
fetch-registry: false
register-with-eureka: false
eureka-server-total-connections: 200
serviceUrl:
#添加認證密碼,用戶名
defaultZone: http://${spring.security.user.name}:${spring.security.user.password}@${eureka.instance.hostname}:${server.port}/eureka/
3.4 修改啓動類加註解:@EnableEurekaServer
package com.guo.eurekaserver;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
@SpringBootApplication
@EnableEurekaServer
public class EurekaServerApplication {
public static void main(String[] args) {
SpringApplication.run(EurekaServerApplication.class, args);
}
}
3.5報錯無法註冊到eureka-server,新版本的security默認開啓csrf了,添加一個文件(建在啓動類裏面)關掉就好了。
package com.guo.eurekaserver;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
@EnableWebSecurity
@Configuration
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {
@Override
protected void configure(HttpSecurity http) throws Exception {
http.csrf().disable(); // 關閉csrf
http.authorizeRequests().anyRequest().authenticated().and().httpBasic(); // 開啓認證
}
}
啓動eureka server,然後訪問http://localhost:10086/eureka, 界面如下, "No instances available" 表示無client註冊
4. 創建Eureka Client
4.1 用spring boot創建子工程
4.2. 創建主類EurekaClientApplication,使用@EnableEurekaClient註解表明是client
package com.guo.eurekaclient;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
@SpringBootApplication
@EnableDiscoveryClient
public class EurekaClientApplication {
public static void main(String[] args) {
SpringApplication.run(EurekaClientApplication.class, args);
}
}
4.3 eureka client的配置文件application.yml
spring:
application:
name: boot-service
profiles:
active: dev
application-dev.yml
server:
port: 9081
spring:
application:
name: client-a
eureka:
client:
serviceUrl:
#添加認證用戶名,密碼
defaultZone: http://admin:[email protected]:8081/eureka/
4.4 寫一個接口
package com.guo.service.impl;
import com.guo.service.UserService;
import org.springframework.stereotype.Service;
@Service
public class UserServiceImpl implements UserService {
public String getUser(){
return "hello world!";
}
}
package com.guo.controller;
import com.guo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class UserController {
@Autowired
UserService userService;
@RequestMapping("/getUser")
public String getUser(){
return userService.getUser();
}
}
4.5 Client啓動後, 可以訪問http://localhost:8762
4.6 如果訪問不到,檢查啓動類是否在最外層資源包裏面
5.創建Eureka 消費者(服務的調用者)
5.1 創建consumer項目(同4.1,與服務註冊一樣)
5.2 pom,application.yml文件(跟服務註冊一樣)
5.3 啓動類加入 RestTemplate
package com.guo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;
@SpringBootApplication
public class EurekaConsumer2Application {
public static void main(String[] args) {
SpringApplication.run(EurekaConsumer2Application.class, args);
}
@Bean
RestTemplate restTemplate() {
return new RestTemplate();
}
}
5.4 controller 層調用
package com.guo.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
@RestController
public class GetUserController {
@Autowired
RestTemplate restTemplate;
@RequestMapping("/user")
public String userString() {
String str = restTemplate.getForObject("http://localhost:9081/getUser", String.class);
return str;
}
}
5.5 restTemplate返回類型:string.class vo.class 扥類型。
5.6 調用consumer的方法http://localhost:10082/user,成功後的結果: