Question

如何在Camel的2.16.1 Loop之后获得聚合消息？我得到的唯一输出是在循环中处理的最后一条消息。

我的循环迭代三次，并且聚合器在单个String中组合了主体。循环看起来像这样：

from("timer:begin?repeatCount=1&delay=1")
.routeId("timer")
.to("direct:loop")
.log("Body after Loop Route: ${body}");

from("direct:loop")
.routeId("loop")
.loop(3)
    .setBody().simple("Hello ${exchangeProperty.CamelLoopIndex}")
    .log("Body in Loop: ${body}")
    .aggregate(new AggregationStrategy() {

        public Exchange aggregate(Exchange oldExchange, Exchange newExchange) {
            if (oldExchange == null) {
                return newExchange;
            }
            else {
                String oldBody = oldExchange.getIn().getBody(String.class);
                String newBody = oldBody + ", " + newExchange.getIn().getBody(String.class);
                newExchange.getIn().setBody(newBody);
                return newExchange;
            }
        }
    }).constant(true).completionSize(3)
    .log("Body after Aggregate: ${body}")
.end();

问题是在 timer -route中我无法访问聚合消息。相反，示例中的 timer -route输出 Hello 2 ，如下所示：

Body in Loop: Hello 0
Body in Loop: Hello 1
Body in Loop: Hello 2
Body after Aggregate: Hello 0, Hello 1, Hello 2
Body after Loop Route: Hello 2

Answer 1

我没有弄清楚怎么用Loop做这件事。然而，它在Camel网站上说Loop是

主要在测试期间有用。

所以我走了另一条路。

所以，要循环遍历某些值，比如在循环中获取聚合结果，我修改了使用Splitter和Aggregator这样的路径

from("timer:begin?repeatCount=1&delay=1")
.routeId("timer")
.to("direct:splitter-loop")
.log("Body after Loop Route: ${body}");

from("direct:splitter-loop")
.routeId("splitter-loop")
.process(exchange -> {
    // Add items that you want to iterate over to body or header
    // and later use splitter over those items.
    List<String> loopIndex = new ArrayList<String>();
    loopIndex.add("1");
    loopIndex.add("2");
    loopIndex.add("3");
    exchange.getOut().setBody(loopIndex);
})
.split(body(), new StringAggregator())
    .setBody().simple("Hello ${body}")
    .log("Body in Loop: ${body}")
.end()
.log("Body after Aggregate: ${body}");

StringAggregator之前的情况如下：

public class StringAggregator implements AggregationStrategy {

    public Exchange aggregate(Exchange oldExchange, Exchange newExchange) {
        if (oldExchange == null) {
            return newExchange;
        }
        else {
            String oldBody = oldExchange.getIn().getBody(String.class);
            String newBody = oldBody + ", " + newExchange.getIn().getBody(String.class);
            newExchange.getIn().setBody(newBody);
            return newExchange;
        }
    }
}

此路线现在为我提供了所需的汇总结果

Body in Loop: Hello 1
Body in Loop: Hello 2
Body in Loop: Hello 3
Body after Aggregate: Hello 1, Hello 2, Hello 3
Body after Loop Route: Hello 1, Hello 2, Hello 3

如何在Camel中循环后访问聚合消息

1 个答案: