分布式框架之：Dubbo + Zookeeper （二）

分布式框架之：Dubbo + Zookeeper （二）

目录：

1.建立聚合工程

dubbo-zookeeper [pom.xml]

<?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>
        <artifactId>dubbo-zookeeper</artifactId>
        <groupId>com.dahuilang</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    
    <groupId>com.dahuilang</groupId>
    <artifactId>dubbo-provider</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>dubbo-provider</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
        <zookeeper.version>3.4.13</zookeeper.version>
        <dubbo.version>0.2.0</dubbo.version>
    </properties>

    <dependencies>


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


        <dependency>
            <groupId>com.alibaba.boot</groupId>
            <artifactId>dubbo-spring-boot-starter</artifactId>
            <version>${dubbo.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.zookeeper</groupId>
            <artifactId>zookeeper</artifactId>
            <version>${zookeeper.version}</version>
            <exclusions>
                <exclusion>
                    <groupId>org.slf4j</groupId>
                    <artifactId>slf4j-log4j12</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>log4j</groupId>
                    <artifactId>log4j</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>com.dahuilang</groupId>
            <artifactId>dubbo-api</artifactId>
            <version>0.0.1-SNAPSHOT</version>
            <scope>compile</scope>
        </dependency>

    </dependencies>

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

</project>
dubbo-api [pom.xml]
<?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>
        <artifactId>dubbo-zookeeper</artifactId>
        <groupId>com.dahuilang</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <groupId>com.dahuilang</groupId>
    <artifactId>dubbo-api</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>dubbo-api</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

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

</project>
dubbo-provider [pom.xml]
<?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>
        <artifactId>dubbo-zookeeper</artifactId>
        <groupId>com.dahuilang</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>

    <groupId>com.dahuilang</groupId>
    <artifactId>dubbo-provider</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>dubbo-provider</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
        <zookeeper.version>3.4.13</zookeeper.version>
        <dubbo.version>0.2.0</dubbo.version>
    </properties>

    <dependencies>


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


        <dependency>
            <groupId>com.alibaba.boot</groupId>
            <artifactId>dubbo-spring-boot-starter</artifactId>
            <version>${dubbo.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.zookeeper</groupId>
            <artifactId>zookeeper</artifactId>
            <version>${zookeeper.version}</version>
            <exclusions>
                <exclusion>
                    <groupId>org.slf4j</groupId>
                    <artifactId>slf4j-log4j12</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>log4j</groupId>
                    <artifactId>log4j</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>com.dahuilang</groupId>
            <artifactId>dubbo-api</artifactId>
            <version>0.0.1-SNAPSHOT</version>
            <scope>compile</scope>
        </dependency>

    </dependencies>

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

</project>
dubbo-customer [pom.xml]
<?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>
        <artifactId>dubbo-zookeeper</artifactId>
        <groupId>com.dahuilang</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <groupId>com.dahuilang</groupId>
    <artifactId>dubbo-customer</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>dubbo-customer</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
        <zookeeper.version>3.4.13</zookeeper.version>
        <dubbo.version>0.2.0</dubbo.version>
    </properties>

    <dependencies>

        <dependency>
            <groupId>com.dahuilang</groupId>
            <artifactId>dubbo-api</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>

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

        <dependency>
            <groupId>com.alibaba.boot</groupId>
            <artifactId>dubbo-spring-boot-starter</artifactId>
            <version>${dubbo.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.zookeeper</groupId>
            <artifactId>zookeeper</artifactId>
            <version>${zookeeper.version}</version>
            <exclusions>
                <exclusion>
                    <groupId>org.slf4j</groupId>
                    <artifactId>slf4j-log4j12</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>log4j</groupId>
                    <artifactId>log4j</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>


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

</project>

2.项目结构

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package com.dahuilang.dubboapi.service;

public interface HelloService {
    String sayHello(String name);
}

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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

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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

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http://localhost:8090/sayHello?name=dahuilang
在这里插入图片描述

[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<String> 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);
    }
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