如何在駱駝處理器中使用屬性佔位符

Question

我正在用駱駝編寫一些路由，並且我想使用處理器進行一些轉換。我有一個屬性文件，它工作正常。

from(URI_LOG) 
    .routeId("{{PREFIX_LOG}}.prepareForMQ") 
    .log("Mail to: {{MAIL}}") //The value is read from a property file 
    .process(new ProcessorPrepareMail()) 
    .log("${body}"); 

現在...我想讀取處理器中{{MAIL}}的值，但我不知道如何。

我想這些東西：

public class ProcessorPrepareMail implements Processor 
{ 

    @Override 
    public void process(Exchange exchange) throws Exception 
    { 
     //Plan A: Does not work.... I get an empty String 
     String mail = exchange.getProperty("MAIL", String.class); 

     //Plan B: Does not work.... I get the String "{{MAIL}}" 
     Language simple = exchange.getContext().resolveLanguage("simple"); 
     Expression expresion = simple.createExpression("{{MAIL}}"); 
     String valor = expresion.evaluate(exchange, String.class); 

     //Plan C: Does not work. It activates the default error handler 
     Language simple = exchange.getContext().resolveLanguage("simple"); 
     Expression expresion = simple.createExpression("${MAIL}"); 
     String valor = expresion.evaluate(exchange, String.class); 
    } 
} 

你能幫助我嗎？

感謝

Answer 1

上有CamelContext API來做到這一點：

String mail = exchange.getContext().resolvePropertyPlaceholders("{{MAIL}}");