Java 如何检索骆驼路由XML中的exchange属性？

我得在路线上绕一圈。我的路线看起来像

<camel:loop>
      <camel:constant>${property.x}</camel:constant> 
</camel:loop>

运行此命令时，请输入x=4的值。我希望访问骆驼路线XML文件中的x

Date date = new Date();
    this.LOGGER
            .info("\n****WELCOME TO THE REQUEST OF CHECK PROCESSOR**");
    int y=4;
    Integer a=new Integer(y);
    exchange.setProperty(x,a);
    int k=(Integer) exchange.getProperty(x);
    this.LOGGER
    .info("\n***WELCOME TO THE REQUEST OF CHECK PROCESSOR ENDINGGGGGGGG***"+"a=   "+a+"  Y=  "+y+"  x=   "+exchange.getProperty(x)+"  k=  "+k);