队列使用手册_Java SDK_SDK 参考_消息服务 MNS-阿里云

本文档介绍如何使用java sdk中的sample代码，完成创建队列、发送消息、接收删除消息和删除队列操作。

1. 准备

下载最新版java sdk，解压到aliyun-sdk-mns-samples文件夹；
用Eclipse导入Maven工程，选中aliyun-sdk-mns-samples文件夹；
在用户目录(Linux系统为”/home/YOURNAME/“目录或者Windows系统为 “C:\Users\YOURNAME”目录)中创建.aliyun-mns.properties文件，并填写服务地址、AccessKeyID和AccessKeySecret：
- AccessKeyId、AccessKeySecret
  - 访问阿里云API的密钥对；
  - 如果使用主账号访问，登陆阿里云 AccessKey 管理页面创建、查看；
  - 如果使用子账号访问，请登录阿里云访问控制控制台查看；
- Endpoint
  - 访问MNS的接入地址，登陆MNS控制台单击右上角 获取Endpoint 查看;
  - 不同地域的接入地址不同，分为公网以及内网域名；

2. 创建队列

下面给出了创建队列的代码段（队列详细信息请参考详情）;

public class CreateQueueDemo {
    public static void main(String[] args) {
        CloudAccount account = new CloudAccount("YourAccessId", "YourAccessKey", "MNSEndpoint");
        MNSClient client = account.getMNSClient(); // 在程序中，CloudAccount以及MNSClient单例实现即可，多线程安全
        String queueName = "TestQueue";
        QueueMeta meta = new QueueMeta(); //生成本地QueueMeta属性，有关队列属性详细介绍见https://help.aliyun.com/document_detail/27476.html
        meta.setQueueName(queueName);  // 设置队列名
        meta.setPollingWaitSeconds(15);
        meta.setMaxMessageSize(2048L);
        try {
            CloudQueue queue = client.createQueue(meta);
        } catch (ClientException ce)
        {
            System.out.println("Something wrong with the network connection between client and MNS service."
                   + "Please check your network and DNS availablity.");
            ce.printStackTrace();
        } catch (ServiceException se)
        {
            se.printStackTrace();
            logger.error("MNS exception requestId:" + se.getRequestId(), se);
            if (se.getErrorCode() != null) {
                if (se.getErrorCode().equals("QueueNotExist"))
                {
                    System.out.println("Queue is not exist.Please create before use");
                } else if (se.getErrorCode().equals("TimeExpired"))
                {
                    System.out.println("The request is time expired. Please check your local machine timeclock");
                }
            /*
            you can get more MNS service error code from following link:
            https://help.aliyun.com/document_detail/mns/api_reference/error_code/error_code.html
            */
            }
        } catch (Exception e)
        {
            System.out.println("Unknown exception happened!");
            e.printStackTrace();
        }
        client.close();  // 程序退出时，需主动调用client的close方法进行资源释放
    }
}

3. 发送消息

创建完队列之后，就可以向队列发送消息

public class ProducerDemo {
    public static void main(String[] args) {
        CloudAccount account = new CloudAccount("YourAccessId", "YourAccessKey", "MNSEndpoint");
        MNSClient client = account.getMNSClient(); // 在程序中，CloudAccount以及MNSClient单例实现即可，多线程安全
        try {
            CloudQueue queue = client.getQueueRef("TestQueue");
            Message message = new Message();
            message.setMessageBody("I am test message ");
            Message putMsg = queue.putMessage(message);
            System.out.println("Send message id is: " + putMsg.getMessageId());
        } catch (ClientException ce)
        {
            System.out.println("Something wrong with the network connection between client and MNS service."
                   + "Please check your network and DNS availablity.");
            ce.printStackTrace();
        } catch (ServiceException se)
        {
            se.printStackTrace();
            logger.error("MNS exception requestId:" + se.getRequestId(), se);
            if (se.getErrorCode() != null) {
                if (se.getErrorCode().equals("QueueNotExist"))
                {
                    System.out.println("Queue is not exist.Please create before use");
                } else if (se.getErrorCode().equals("TimeExpired"))
                {
                    System.out.println("The request is time expired. Please check your local machine timeclock");
                }
            /*
            you can get more MNS service error code from following link:
            https://help.aliyun.com/document_detail/mns/api_reference/error_code/error_code.html
            */
            }
        } catch (Exception e)
        {
            System.out.println("Unknown exception happened!");
            e.printStackTrace();
        }
        client.close();  // 程序退出时，需主动调用client的close方法进行资源释放
    }
}

4. 接收和删除消息

队列中已经发送了1条消息，下面是从队列中取出并删除该条消息。

public class ConsumerDemo {
    public static void main(String[] args) {
        CloudAccount account = new CloudAccount("YourAccessId", "YourAccessKey", "MNSEndpoint");
        MNSClient client = account.getMNSClient(); // 在程序中，CloudAccount以及MNSClient单例实现即可，多线程安全
        try{
            CloudQueue queue = client.getQueueRef("TestQueue");
            Message popMsg = queue.popMessage();
            if (popMsg != null){
                System.out.println("message handle: " + popMsg.getReceiptHandle());
                System.out.println("message body: " + popMsg.getMessageBodyAsString());
                System.out.println("message id: " + popMsg.getMessageId());
                System.out.println("message dequeue count:" + popMsg.getDequeueCount());
                //删除已经取出消费的消息
                 queue.deleteMessage(popMsg.getReceiptHandle());
                    System.out.println("delete message successfully.\n");
            }
            else{
                System.out.println("message not exist in TestQueue.\n");
            }
        } catch (ClientException ce)
        {
            System.out.println("Something wrong with the network connection between client and MNS service."
                    + "Please check your network and DNS availablity.");
            ce.printStackTrace();
        } catch (ServiceException se)
        {
            se.printStackTrace();
            logger.error("MNS exception requestId:" + se.getRequestId(), se);
            if (se.getErrorCode() != null) {
                if (se.getErrorCode().equals("QueueNotExist"))
                {
                    System.out.println("Queue is not exist.Please create before use");
                } else if (se.getErrorCode().equals("TimeExpired"))
                {
                    System.out.println("The request is time expired. Please check your local machine timeclock");
                }
            /*
            you can get more MNS service error code from following link:
            https://help.aliyun.com/document_detail/mns/api_reference/error_code/error_code.html
            */
            }
        } catch (Exception e)
        {
            System.out.println("Unknown exception happened!");
            e.printStackTrace();
        }
        client.close();
    }
}

5. 删除队列

public class DeleteQueueDemo {
    public static void main(String[] args) {
        CloudAccount account = new CloudAccount("YourAccessId", "YourAccessKey", "MNSEndpoint");
        MNSClient client = account.getMNSClient(); // 在程序中，CloudAccount以及MNSClient单例实现即可，多线程安全
        try{
            CloudQueue queue = client.getQueueRef("TestQueue");
            queue.delete();
        } catch (ClientException ce)
        {
            System.out.println("Something wrong with the network connection between client and MNS service."
                    + "Please check your network and DNS availablity.");
            ce.printStackTrace();
        } catch (ServiceException se)
        {
            se.printStackTrace();
        } catch (Exception e)
        {
            System.out.println("Unknown exception happened!");
            e.printStackTrace();
        }
        client.close();
    }
}