- 分布式框架之：Dubbo + Zookeeper （二）
- 1.建立聚合工程
- dubbo-zookeeper [pom.xml]
- dubbo-api [pom.xml]
- dubbo-provider [pom.xml]
- dubbo-customer [pom.xml]
- 2.项目结构
- application.yml
- application.yml
- 启动
dubbo-api [pom.xml]4.0.0 dubbo-zookeeper com.dahuilang 0.0.1-SNAPSHOT com.dahuilang dubbo-provider 0.0.1-SNAPSHOT dubbo-provider Demo project for Spring Boot 1.8 3.4.13 0.2.0 org.springframework.boot spring-boot-starter com.alibaba.boot dubbo-spring-boot-starter ${dubbo.version} org.apache.zookeeper zookeeper ${zookeeper.version} org.slf4j slf4j-log4j12 log4j log4j org.springframework.boot spring-boot-starter-test test org.junit.vintage junit-vintage-engine com.dahuilang dubbo-api 0.0.1-SNAPSHOT compile org.springframework.boot spring-boot-maven-plugin
dubbo-provider [pom.xml]4.0.0 dubbo-zookeeper com.dahuilang 0.0.1-SNAPSHOT com.dahuilang dubbo-api 0.0.1-SNAPSHOT dubbo-api Demo project for Spring Boot 1.8 org.springframework.boot spring-boot-starter org.springframework.boot spring-boot-starter-test test org.junit.vintage junit-vintage-engine org.springframework.boot spring-boot-maven-plugin
dubbo-customer [pom.xml]4.0.0 dubbo-zookeeper com.dahuilang 0.0.1-SNAPSHOT com.dahuilang dubbo-provider 0.0.1-SNAPSHOT dubbo-provider Demo project for Spring Boot 1.8 3.4.13 0.2.0 org.springframework.boot spring-boot-starter com.alibaba.boot dubbo-spring-boot-starter ${dubbo.version} org.apache.zookeeper zookeeper ${zookeeper.version} org.slf4j slf4j-log4j12 log4j log4j org.springframework.boot spring-boot-starter-test test org.junit.vintage junit-vintage-engine com.dahuilang dubbo-api 0.0.1-SNAPSHOT compile org.springframework.boot spring-boot-maven-plugin
2.项目结构4.0.0 dubbo-zookeeper com.dahuilang 0.0.1-SNAPSHOT com.dahuilang dubbo-customer 0.0.1-SNAPSHOT dubbo-customer Demo project for Spring Boot 1.8 3.4.13 0.2.0 com.dahuilang dubbo-api 0.0.1-SNAPSHOT org.springframework.boot spring-boot-starter-web com.alibaba.boot dubbo-spring-boot-starter ${dubbo.version} org.apache.zookeeper zookeeper ${zookeeper.version} org.slf4j slf4j-log4j12 log4j log4j org.springframework.boot spring-boot-starter-test test org.junit.vintage junit-vintage-engine org.springframework.boot spring-boot-maven-plugin
package com.dahuilang.dubboapi.service;
public interface HelloService {
String sayHello(String name);
}
package com.dahuilang.dubboprovider.service.impl;
import com.alibaba.dubbo.config.annotation.Service;
import com.dahuilang.dubboapi.service.HelloService;
@Service // 注册服务
public class HelloServiceImpl implements HelloService {
@Override
public String sayHello(String name) {
return "Hello, " + name;
}
}
application.yml
server:
port: 8091
dubbo:
application:
name: dubbo-provider
protocol:
name: dubbo
port: 20880
registry:
address: zookeeper://127.0.0.1:2181
package com.dahuilang.dubbocustomer.controller;
import com.alibaba.dubbo.config.annotation.Reference;
import com.dahuilang.dubboapi.service.HelloService;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class HelloController {
@Reference //dubbo引用服务
private HelloService helloService;
@GetMapping("/sayHello")
private String sayHello(@RequestParam String name){
System.out.println("调用sayHello成功了..." + " name:" + name);
return helloService.sayHello(name);
}
}
application.yml
server:
port: 8090
dubbo:
application:
name: dubbo-customer
registry:
address: zookeeper://127.0.0.1:2181
启动
http://localhost:8090/sayHello?name=dahuilang
[zk: localhost:2181(CONNECTED) 18] ls /dubbo [com.dahuilang.dubbo.service.TestService, com.dahuilang.dubboapi.service.HelloService, mapping]
拓展
set path data [version] 命令 修改操作.每次修改完以后版本号会变
delete path [version] 删除节点数据，可以带版本号，实现乐观锁机制
按顺序去获取锁
@Override
public void lock() {
// 如果获取不到锁，阻塞等待
if (!tryLock()) {
// 没获得锁，阻塞自己
waitForLock();
// 再次尝试
lock();
}
}
// 尝试加锁
@Override
public boolean tryLock() {
// 创建临时顺序节点
if (this.currentPath == null) {
// 在lockPath节点下面创建临时顺序节点
currentPath = this.client.createEphemeralSequential(LockPath + "/", "lockpath");
}
// 获得所有的子节点
List children = this.client.getChildren(LockPath);
// 排序list
Collections.sort(children);
// 判断当前节点是否是最小的,如果是最小的节点,则表明此这个client可以获取锁
if (currentPath.equals(LockPath + "/" + children.get(0))) {
return true;
} else {
// 如果不是当前最小的sequence,取到前一个临时节点
// 1.单独获取临时节点的顺序号
// 2.查找这个顺序号在children中的下标
// 3.存储前一个节点的完整路径
int curIndex = children.indexOf(currentPath.substring(LockPath.length() + 1));
beforePath = LockPath + "/" + children.get(curIndex - 1);
}
return false;
}
//
private void waitForLock() {
CountDownLatch cdl = new CountDownLatch(1);
// 注册watcher
IZkDataListener listener = new IZkDataListener() {
@Override
public void handleDataDeleted(String dataPath) throws Exception {
System.out.println("监听到前一个节点被删除了");
cdl.countDown();
}
@Override
public void handleDataChange(String dataPath, Object data) throws Exception {
}
};
// 监听前一个临时节点
client.subscribeDataChanges(this.beforePath, listener);
// 前一个节点还存在,则阻塞自己
if (this.client.exists(this.beforePath)) {
try {
// 直至前一个节点释放锁,才会继续往下执行
cdl.await();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
// 醒来后,表明前一个临时节点已经被删除,此时客户端可以获取锁 && 取消watcher监听
client.unsubscribeDataChanges(this.beforePath, listener);
}
