SpringCloud学习笔记(四)_ZooKeeper注册中心

基于Spring Cloud实现服务的发布与调用。而在18年7月份，Eureka2.0宣布停更了，将不再进行开发，所以对于公司技术选型来说，可能会换用其他方案做注册中心。本章学习便是使用ZooKeeper作为注册中心。

本章使用的zookeeper版本是 3.6.0

项目架构图如下：

搭建服务提供者

1、新建一个maven项目（test-springcloud-provider-payment8004）

结构如下：

2、引入依赖，编辑pom文件

1 <!-- spring-cloud 整合 zookeeper -->
2 <dependency>
3     <groupId>org.springframework.cloud</groupId>
4     <artifactId>spring-cloud-starter-zookeeper-discovery</artifactId>
5 </dependency>

完整pom文件如下：

 1 <?xml version="1.0" encoding="UTF-8"?>2 <project xmlns="http://maven.apache.org/POM/4.0.0"3          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"4          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">5     <parent>6         <artifactId>test-springcloud</artifactId>7         <groupId>com.test</groupId>8         <version>1.0-SNAPSHOT</version>9     </parent>
10     <modelVersion>4.0.0</modelVersion>
11 
12     <artifactId>test-springcloud-provider-payment8004</artifactId>
13 
14     <dependencies>
15 
16         <!-- spring-cloud 整合 zookeeper -->
17         <dependency>
18             <groupId>org.springframework.cloud</groupId>
19             <artifactId>spring-cloud-starter-zookeeper-discovery</artifactId>
20             <!-- 排除自带的zookeeper jar包 -->
21             <exclusions>
22                 <exclusion>
23                     <groupId>org.apache.zookeeper</groupId>
24                     <artifactId>zookeeper</artifactId>
25                 </exclusion>
26             </exclusions>
27         </dependency>
28 
29         <!-- zookeeper 引入对应版本的zookeeper -->
30         <dependency>
31             <groupId>org.apache.zookeeper</groupId>
32             <artifactId>zookeeper</artifactId>
33             <version>3.6.0</version>
34             <exclusions>
35                 <exclusion>
36                     <groupId>org.slf4j</groupId>
37                     <artifactId>slf4j-log4j12</artifactId>
38                 </exclusion>
39                 <exclusion>
40                     <groupId>log4j</groupId>
41                     <artifactId>log4j</artifactId>
42                 </exclusion>
43             </exclusions>
44         </dependency>
45 
46         <!-- spring boot -->
47         <dependency>
48             <groupId>org.springframework.boot</groupId>
49             <artifactId>spring-boot-starter-web</artifactId>
50         </dependency>
51         <dependency>
52             <groupId>org.springframework.boot</groupId>
53             <artifactId>spring-boot-starter-actuator</artifactId>
54         </dependency>
55 
56         <dependency>
57             <groupId>org.springframework.boot</groupId>
58             <artifactId>spring-boot-devtools</artifactId>
59             <scope>runtime</scope>
60             <optional>true</optional>
61         </dependency>
62         <dependency>
63             <groupId>org.projectlombok</groupId>
64             <artifactId>lombok</artifactId>
65             <optional>true</optional>
66         </dependency>
67 
68         <dependency>
69             <groupId>org.springframework.boot</groupId>
70             <artifactId>spring-boot-starter-test</artifactId>
71             <scope>test</scope>
72         </dependency>
73 
74     </dependencies>
75 
76     <build>
77         <finalName>test-springcloud-provider-payment8004</finalName>
78     </build>
79 
80 </project>

pom.xml

需要注意，由于通过spring-cloud-starter-zookeeper-discovery依赖引入的zookeeper jar包，于zookeeper服务器版本不一致导致的，导致项目启动失败

报错：Caused by: org.apache.zookeeper.KeeperException$UnimplementedException: KeeperErrorCode = Unimplemented for /services/xx/xxx

解决：引入对于版本的 zookeeper jar包，本章使用的zookeeper版本是3.6.0，所以引入zookeeper-3.6.0.jar，如下：

 1 <!-- spring-cloud 整合 zookeeper -->2 <dependency>3     <groupId>org.springframework.cloud</groupId>4     <artifactId>spring-cloud-starter-zookeeper-discovery</artifactId>5     <!-- 排除自带的zookeeper jar包 -->6     <exclusions>7         <exclusion>8             <groupId>org.apache.zookeeper</groupId>9             <artifactId>zookeeper</artifactId>
10         </exclusion>
11     </exclusions>
12 </dependency>
13 
14 <!-- zookeeper 引入对应版本的zookeeper -->
15 <dependency>
16     <groupId>org.apache.zookeeper</groupId>
17     <artifactId>zookeeper</artifactId>
18     <version>3.6.0</version>
19     <exclusions>
20         <exclusion>
21             <groupId>org.slf4j</groupId>
22             <artifactId>slf4j-log4j12</artifactId>
23         </exclusion>
24         <exclusion>
25             <groupId>log4j</groupId>
26             <artifactId>log4j</artifactId>
27         </exclusion>
28     </exclusions>
29 </dependency>

pom.xml

3、编辑配置文件application.yml

 1 # 端口2 server:3   port: 80044 5 spring:6   application:7     name: cloud-payment-service8   cloud:9     zookeeper:
10       # 集群模式用逗号隔开
11       connect-string: 127.0.0.1:2181

4、编写主启动类

1 // 启用服务发现
2 @EnableDiscoveryClient
3 @SpringBootApplication
4 public class PaymentMain8004 {
5     public static void main(String[] args) {
6         SpringApplication.run(PaymentMain8004.class, args);
7     }
8 }

5、编写Controller

 1 @RestController2 @Slf4j3 public class PaymentController {4 5     @Value("${server.port}")6     private String serverPort;7 8     @RequestMapping(value = "payment/zk")9     public String paymentzk(){
10         return "springcloud with zookeeper：" + serverPort + "\t" + UUID.randomUUID();
11     }
12 }

6、启动项目，测试

1）使用地址：http://localhost:8004/payment/zk

2）使用zookeeper客户端连接到zookeeper服务中，查看节点信息

json格式如下：

 1 {2     "name": "cloud-payment-service",3     "id": "4f3db6b1-7d3a-4b3e-ac7a-159289573440",4     "address": "192.168.1.4",5     "port": 8004,6     "sslPort": null,7     "payload": {8         "@class": "org.springframework.cloud.zookeeper.discovery.ZookeeperInstance",9         "id": "application-1",
10         "name": "cloud-payment-service",
11         "metadata": {}
12     },
13     "registrationTimeUTC": 1586166066913,
14     "serviceType": "DYNAMIC",
15     "uriSpec": {
16         "parts": [{
17             "value": "scheme",
18             "variable": true
19         }, {
20             "value": "://",
21             "variable": false
22         }, {
23             "value": "address",
24             "variable": true
25         }, {
26             "value": ":",
27             "variable": false
28         }, {
29             "value": "port",
30             "variable": true
31         }]
32     }
33 }

View Code

7、测试zookeeper的服务节点是临时节点还是永久节点？

通过关闭应用服务，在zookeeper客户端中是用命令：ls /services/cloud-payment-service，

查看服务之后存在，然后启动服务，查看节点ID是否相同

通过测试验证：zookeeper的服务节点是临时节点

搭建服务消费者

1、新建一个maven项目（test-springcloud-order7999）

项目结构如下：

2、引入pom依赖，同上（与服务提供者依赖相同）

3、编辑application.yml文件

 1 # 端口2 server:3   port: 79994 5 spring:6   application:7     name: cloud-order8   cloud:9     zookeeper:
10       connect-string: 127.0.0.1

4、编写主启动类

1 @SpringBootApplication
2 public class OrderMain7999 {
3     public static void main(String[] args) {
4         SpringApplication.run(OrderMain7999.class, args);
5     }
6 }

5、编辑配置类，注入RestTemplate对象

 1 @Configuration2 public class AppConfig {3 4     /**5      * 注入restTemplate，请用请求rest接口6      * @return7      */8     @Bean9     // 标注此注解后，RestTemplate就具有了客户端负载均衡能力
10     // 负载均衡技术依赖于的是Ribbon组件~
11     // RestTemplate都塞入一个loadBalancerInterceptor 让其具备有负载均衡的能力
12     @LoadBalanced
13     public RestTemplate restTemplate(){
14         return new RestTemplate();
15     }
16 }

6、编辑Controller

 1 @RestController2 @Slf4j3 public class OrderController {4 5     public static final String PAYMENT_URL = "http://cloud-payment-service";6 7     @Autowired8     private RestTemplate restTemplate;9 
10     @GetMapping("/consumer/payment/zk")
11     public String paymentzk(){
12         return restTemplate.getForObject(PAYMENT_URL + "/payment/zk", String.class);
13     }
14 
15 }

7、启动项目测试

1）访问地址：http://localhost:7999/consumer/payment/zk

2）使用zookeeper客户端登录zookeeper服务器查看