代码：
maven依赖：
<groupId>com.junlaninfo</groupId>
<artifactId>sentry</artifactId>
<version>1.0-SNAPSHOT</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.0.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>com.101tec</groupId>
<artifactId>zkclient</artifactId>
<version>0.10</version>
<exclusions>
<exclusion>
<artifactId>slf4j-api</artifactId>
<groupId>org.slf4j</groupId>
</exclusion>
<exclusion>
<artifactId>log4j</artifactId>
<groupId>log4j</groupId>
</exclusion>
<exclusion>
<artifactId>slf4j-log4j12</artifactId>
<groupId>org.slf4j</groupId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
|
application.properties配置文件，后续步骤会把server.port 改为8080/8081/8082，分别启动，模拟集群的效果
server.port=8082 |
Controller
package com.junlaninfo.controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
/**
* Created by 辉 on 2020/7/4.
*/
@RestController
public class IndexController {
@GetMapping("/getInfo")
public String getInfo(){
return "当前是否为主节点："+Sentry.isMaster;
}
}
|
ZookeeperRunner
package com.junlaninfo.controller;
import org.I0Itec.zkclient.IZkDataListener;
import org.I0Itec.zkclient.ZkClient;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.stereotype.Component;
/**
* Created by 辉 on 2020/7/4.
*/
@Component
public class ZookeeperRunner implements ApplicationRunner {
// 创建zk连接
ZkClient zkClient = null;
private String path = "/election";
@Value("${server.port}")
private String serverPort;
@Override
public void run(ApplicationArguments applicationArguments) throws Exception {
System.out.println("项目已启动就执行这个方法");
zkClient = new ZkClient("192.168.196.175:2181");
createEphemeral(); //尝试创建节点
//创立监听watcher，看节点有无被删除和改变
zkClient.subscribeDataChanges(path, new IZkDataListener() {
@Override
public void handleDataChange(String s, Object o) throws Exception {
}
@Override
public void handleDataDeleted(String s) throws Exception {
// 主节点已经挂了，重新选举
System.out.println("主节点已经挂了，重新开始选举");
createEphemeral();
}
});
}
private void createEphemeral() {
try {
zkClient.createEphemeral(path); //创建临时节点
Sentry.isMaster = true; //创建节点要是成功，就把ismaster置为true，创建不成功就会出异常
} catch (Exception e) {
Sentry.isMaster = false;
}
}
}
|
判断是否为主节点的标识
package com.junlaninfo.controller;
import org.springframework.stereotype.Component;
/**
* Created by 辉 on 2020/7/4.
* 这个类主要做一个标识，看它是否为主节点
*/
@Component
public class Sentry {
public static boolean isMaster;
}
|
启动类
package com.junlaninfo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
/**
* Created by 辉 on 2020/7/4.
*/
@SpringBootApplication
public class sentryApplication {
public static void main(String[] args) {
SpringApplication.run(sentryApplication.class);
}
}
|
效果：分别把项目启动为端口号8080 、8081、8082
代码链接：https://github.com/xuexionghui/sentry.git