rabbitmq文档中 factory.setUri();

public class Send {
    private final static String QUEUE_NAME = "hello";

    public static void main(String[] argv) throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setUri("amqp://admin:admin@127.0.0.1:5672");
        factory.setVirtualHost("/va");
        try (Connection connection = factory.newConnection();
             Channel channel = connection.createChannel()) {
            channel.queueDeclare(QUEUE_NAME, false, false, false, null);
            String message = "Hello World!";
            channel.basicPublish("", QUEUE_NAME, null, message.getBytes(StandardCharsets.UTF_8));
        }
    }
}

上面代码没有问题，但是

下面代码为什么报错呢？  

public class Send {
    private final static String QUEUE_NAME = "hello";

    public static void main(String[] argv) throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setUri("amqp://admin:admin@127.0.0.1:5672/va");
        try (Connection connection = factory.newConnection();
             Channel channel = connection.createChannel()) {
            channel.queueDeclare(QUEUE_NAME, false, false, false, null);
            String message = "Hello World!";
            channel.basicPublish("", QUEUE_NAME, null, message.getBytes(StandardCharsets.UTF_8));
        }
    }
}

异常为：

Exception in thread "main" java.io.IOException
	at com.rabbitmq.client.impl.AMQChannel.wrap(AMQChannel.java:129)
	at com.rabbitmq.client.impl.AMQChannel.wrap(AMQChannel.java:125)
	at com.rabbitmq.client.impl.AMQChannel.exnWrappingRpc(AMQChannel.java:147)
	at com.rabbitmq.client.impl.AMQConnection.start(AMQConnection.java:403)
	at com.rabbitmq.client.impl.recovery.RecoveryAwareAMQConnectionFactory.newConnection(RecoveryAwareAMQConnectionFactory.java:64)
	at com.rabbitmq.client.impl.recovery.AutorecoveringConnection.init(AutorecoveringConnection.java:156)
	at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:1106)
	at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:1063)
	at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:1021)
	at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:1182)
	at com.hecatolite.producer.Send.main(Send.java:15)
Caused by: com.rabbitmq.client.ShutdownSignalException: connection error; protocol method: #method<connection.close>(reply-code=530, reply-text=NOT_ALLOWED - vhost va not found, class-id=10, method-id=40)
	at com.rabbitmq.utility.ValueOrException.getValue(ValueOrException.java:66)
	at com.rabbitmq.utility.BlockingValueOrException.uninterruptibleGetValue(BlockingValueOrException.java:36)
	at com.rabbitmq.client.impl.AMQChannel$BlockingRpcContinuation.getReply(AMQChannel.java:502)
	at com.rabbitmq.client.impl.AMQChannel.privateRpc(AMQChannel.java:293)
	at com.rabbitmq.client.impl.AMQChannel.exnWrappingRpc(AMQChannel.java:141)
	... 8 more

因为虚拟主机的名称是  /va ,那么在url中需要把 / 转换成  %2F

factory.setUri("amqp://admin:admin@127.0.0.1:5672/%2Fva");