核心概念

Ref: https://camel.apache.org/manual/latest/book-getting-started.html

ENDPOINT

• A JMS queue.
• A web service.
• A file. A file may sound like an unlikely type of endpoint, until you realize that in some systems one application might write information to a file and, later, another application might read that file.
• An FTP server.
• An email address. A client can send a message to an email address, and a server can read an incoming message from a mail server.
• A POJO (plain old Java object).

CAMELCONTEXT

CamelContext是一个容器。 你可以把它看作Camel的运行时系统，它把所有的东西放在一起。

CamelContext提供了许多有用的服务，最值得注意的是组件，类型转换器，注册表，端点，路由，数据格式和语言。

CAMELTEMPLATE

The CamelTemplate class is a thin wrapper around the CamelContext class。对camelContext的Wrapper。

THE MEANING OF URL, URI, URN AND IRI

The syntax of a URN is urn:<scheme-name>:<unique-identifier>

COMPONENTS

组件是创建EndPoint的。

myCamelContext.getEndpoint("pop3://[email protected]?password=myPassword");

MESSAGE AND EXCHANGE

The Message interface provides an abstraction for a single message, such as a request, reply or exception message. 消息接口提供对单一消息的抽象，比如请求，响应 或者异常消息。

The Exchange interface provides an abstraction for an exchange of messages, that is, a request message and its corresponding reply or exception message. In Camel terminology, the request, reply and exception messages are called in, out and fault messages. Exchange接口提供了消息通道的抽象。

PROCESSOR

消息处理器

ChoiceProcessor

void process(Exchange exchange) throws Exception;

处理器是一个核心Camel概念，代表了一个能够使用，创建或修改传入交换的节点。 在路由期间，交换从一个处理器流向另一个; 因此，您可以将路由视为具有专用处理器作为节点的图形，以及将一个处理器的输出连接到另一个处理器的输入的线路。 许多处理器都是EIP的实现，但是可以轻松实现自己的定制处理器并将其插入到路由中。

ROUTES, ROUTEBUILDERS AND JAVA DSL

A route is the step-by-step movement of a Message from an input queue, through arbitrary types of decision making (such as filters and routers) to a destination queue (if any)

• RouteBuilder
• myCamelContext.addRoutes(builder);