路由属性和交换属性之间的骆驼区别

Question

谁能解释一下这两个属性之间的区别？

@Override
public void setUp() throws Exception {
    context = new DefaultCamelContext(new SimpleRegistry());        
    template = context.createProducerTemplate();

    context.addRoutes(new RouteBuilder() {

        public void configure() throws Exception {              
            PropertiesComponent prop = context.getComponent(
                                      "properties", PropertiesComponent.class);
            prop.setLocation("classpath:test.properties");

            from("direct:start")
            .log("Property: ${properties:a}")
            .process(new Processor() {

                @Override
                public void process(Exchange ex) throws Exception {
                    String a = ex.getProperty("a", String.class);
                    LOG.info("Property: " + a);
                }
            })
            ;
        }
    });

    context.getShutdownStrategy().setTimeout(1);
    context.start();
}

@Test
public void testRoute() throws Exception {
    template.sendBody("direct:start", null);
}

属性文件 (test.properties):

a = a

输出：

2015-09-03 14:38:01,740 | INFO  | route1           | Property: a
2015-09-03 14:38:01,743 | INFO  | CamelTest2       | Property: null

第一行来自.log("${properties:a}")，所以可以找到。但是，String a = ex.getProperty("a", String.class); 不能。两者都是属性，指向同一个属性，对吧？

有什么区别，如何在处理器中找到属性？

Answer 1

Exchange 仅在客户端收到请求时创建。这意味着您的 Camel 处理器只能访问 Message 而不能访问来自外部资源的属性。

Exchange 的属性是消息的元信息。根据文档，

The Exchange also holds meta-data during its entire lifetime stored as properties accessible using the various getProperty(String) methods. The setProperty(String, Object) is used to store a property. For example you can use this to store security, SLA related data or any other information deemed useful throughout processing.

路由属性和交换属性之间的骆驼区别

Camel difference between route properties and exchange properties

java

properties

apache-camel