我有一个通过RabbitMQ发送AMQP消息的应用程序。在http请求上触发消息发送。最近我注意到有些消息似乎丢失了（因为从未发送过）。我还注意到服务器管理的频道列表正在稳步增加。我纠正的第一件事就是在不再需要频道后关闭频道。但是，我仍然不确定我的代码是否正确构造以确保交付。下面是两段代码;第一个是管理连接的单例的一部分（不会在每次调用时重新创建），第二个是发送代码。任何建议/指导将不胜感激。
@Service
public class PersistentConnection {
private static Connection myConnection = null;
private Boolean blocked = false;
@Autowired ApplicationConfiguration applicationConfiguration;
@Autowired ConfigurationService configurationService;
@PostConstruct
private void init() {
}
@PreDestroy
private void destroy() {
try {
myConnection.close();
} catch (IOException e) {
e.printStackTrace();
}
}
public Connection getConnection( ) {
if (myConnection == null) {
start();
}
else if (!myConnection.isOpen()) {
log.warn("AMQP Connection closed. Attempting to start.");
start();
}
return myConnection;
}
private void start() {
log.debug("Building AMQP Connection");
ConnectionFactory factory = new ConnectionFactory();
String ipAddress = applicationConfiguration.getAMQPHost();
String password = applicationConfiguration.getAMQPUser();
String user = applicationConfiguration.getAMQPPassword();
String virtualHost = applicationConfiguration.getAMQPVirtualHost();
String port = applicationConfiguration.getAMQPPort();
try {
factory.setUsername(user);
factory.setPassword(password);
factory.setVirtualHost(virtualHost);
factory.setPort(Integer.parseInt(port));
factory.setHost(ipAddress);
myConnection = factory.newConnection();
}
catch (Exception e) {
e.printStackTrace();
}
myConnection.addBlockedListener(new BlockedListener() {
public void handleBlocked(String reason) throws IOException {
// Connection is now blocked
blocked = true;
}
public void handleUnblocked() throws IOException {
// Connection is now unblocked
blocked = false;
}
});
}
public Boolean isBlocked() {
return blocked;
}
}
/*
* Sends ADT message to AMQP server.
*/
private void send(String routingKey, String message) throws Exception {
String exchange = applicationConfiguration.getAMQPExchange();
String exchangeType = applicationConfiguration.getAMQPExchangeType();
Connection connection = myConnection.getConnection();
Channel channel = connection.createChannel();
channel.exchangeDeclare(exchange, exchangeType);
channel.basicPublish(exchange, routingKey, null, message.getBytes());
// Close the channel if it is no longer needed in this thread
channel.close();
}
答案 0 :(得分：2)
试试这段代码：
@Service
public class PersistentConnection {
private Connection myConnection = null;
private Boolean blocked = false;
@Autowired ApplicationConfiguration applicationConfiguration;
@Autowired ConfigurationService configurationService;
@PostConstruct
private void init() {
start(); /// In this way you can initthe connection and you are sure it is called only one time.
}
@PreDestroy
private void destroy() {
try {
myConnection.close();
} catch (IOException e) {
e.printStackTrace();
}
}
public Connection getConnection( ) {
return myConnection;
}
private void start() {
log.debug("Building AMQP Connection");
ConnectionFactory factory = new ConnectionFactory();
String ipAddress = applicationConfiguration.getAMQPHost();
String password = applicationConfiguration.getAMQPUser();
String user = applicationConfiguration.getAMQPPassword();
String virtualHost = applicationConfiguration.getAMQPVirtualHost();
String port = applicationConfiguration.getAMQPPort();
try {
factory.setUsername(user);
factory.setPassword(password);
factory.setVirtualHost(virtualHost);
factory.setPort(Integer.parseInt(port));
factory.setHost(ipAddress);
myConnection = factory.newConnection();
}
catch (Exception e) {
e.printStackTrace();
}
myConnection.addBlockedListener(new BlockedListener() {
public void handleBlocked(String reason) throws IOException {
// Connection is now blocked
blocked = true;
}
public void handleUnblocked() throws IOException {
// Connection is now unblocked
blocked = false;
}
});
}
public Boolean isBlocked() {
return blocked;
}
}
/*
* Sends ADT message to AMQP server.
*/
private void send(String routingKey, String message) throws Exception {
String exchange = applicationConfiguration.getAMQPExchange();
String exchangeType = applicationConfiguration.getAMQPExchangeType();
Connection connection = myConnection.getConnection();
if (connection!=null){
Channel channel = connection.createChannel();
try{
channel.exchangeDeclare(exchange, exchangeType);
channel.basicPublish(exchange, routingKey, null, message.getBytes());
} finally{
// Close the channel if it is no longer needed in this thread
channel.close();
}
} }
这可能就足够了，你在系统启动时与rabbitmq有联系。
如果你是一个懒惰的单身人士，代码就有点不同了。
我建议不要使用isOpen()方法，请阅读here：
ISOPEN
boolean isOpen（）确定组件当前是否打开。 如果我们正在关闭，将返回false。检查此方法 应该只是为了获取信息，因为竞争条件 - 国家 电话结束后可以改变。而只是执行并尝试捕获 ShutdownSignalException和IOException返回：组件时为true 是公开的，否则是假的
修改**
问题1：
您在寻找HA客户端。
RabbitMQ java客户端默认不支持此功能，因为版本3.3.0仅支持重新连接，请阅读this：
...允许基于Java的客户端在网络后自动重新连接 失败。如果你想确定你的消息，你必须创建一个 强大的客户能够抵抗所有失败。
通常你应该考虑失败，例如： 如果在发布消息期间出现错误会发生什么？
在您的情况下，您只是丢失了消息，您应该手动重新排队消息。
问题2：
我不知道您的代码，但connection == null不应该发生，因为首先调用此过程：
@PostConstruct
private void init() {
start(); /// In this way you can initthe connection and you are sure it is called only one time.
}
无论如何你可以提出异常，问题是： 我该怎么处理我试图发送的消息？
见问题1
我想建议阅读有关HA的更多信息，例如：
使用rabbitmq创建一个可靠的系统并不复杂，但您应该了解一些基本概念。
无论如何..让我知道！