带有节点列表的 Apache Camel XPath [英] Apache Camel XPath with nodelist

问题描述

我想连接来自 Apache Camel XPath 结果的所有值并将其添加到消息上下文中.标题应如下所示:"|value1|value2|valueN|"

I would like to concatenate all values from the Apache Camel XPath result and add it to the message context. The header should look like: "|value1|value2|valueN|"

我的路线如下:

from("direct:test")
.setHeader("key").xpath("//Identifier", List.class)
.to("mock:result")

这样做的最佳方法是什么?有没有办法实现自己的结果类型?

What is the best way for doing that? Is there a way to implement an own result type?

推荐答案

正如 Willem 所说，您必须编写自己的处理器.

As Willem said, you have to write your own processor.

对于这样的小事，我最喜欢的方法是在包含路由定义的类中声明一个函数，返回一个匿名处理器，如下所示:

For such a little thing, my favourite way is to declare a function in the class containing the route definition returning an anonymous Processor like this:

private Processor setHeaderWithIdentifiers() {
    return exchange -> {
        List<String> identifiers = new ArrayList<>();
        NodeList nodes = XPathBuilder.xpath("//Identifier").evaluate(exchange,  NodeList.class);

        for (int i = 0; i < nodes.getLength(); i++) {
            identifiers.add(nodes.item(i).getNodeValue());
        }

        // StringUtils from Apache Commons 3 
        String idAsString = StringUtils.join(identifiers, "|");
        exchange.getIn().setHeader("key", idAsString);
    };
}

有了它，您就不需要找到任何复杂的 XPath 函数，只要处理器代码保持简短，代码就会清晰易懂.

With that, you do not need to find any complex XPath functions and the code remains clear to understand as long the Processor code remains short.

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