失败确认
在生产者通过channel的basicPublish方法发布消息时，通常有几个参数需要设置，为此我们有必要了解清楚这些参数代表的具体含义及其作用，查看Channel接口，会发现存在3个重载的basicPublish方法
void basicPublish(String exchange, String routingKey, BasicProperties props, byte[] body) throws IOException; void basicPublish(String exchange, String routingKey, boolean mandatory, BasicProperties props, byte[] body) throws IOException; void basicPublish(String exchange, String routingKey, boolean mandatory, boolean immediate, BasicProperties props, byte[] body) throws IOException;