Apache Camel 从 String 消息正文中删除撇号

Question

import static java.lang.System.out;

import org.apache.camel.ExchangePattern;
import org.apache.camel.Message;
import org.apache.camel.builder.RouteBuilder;
import org.apache.camel.impl.DefaultCamelContext;

class RequestReplyMessageSample {

    class Replier {

        String reply( final String /*Message*/ /*Exchange*/ request ) {
            out.println( "\n[ERROR] Expected: 'Re'quest', Actual: " + request
                    + "  <-- Am I doing somethig wrong, is this a bug or a feature?\n" );
            return String.format( "**** Replying to %s ****%n", request/*.getMessage()*/ /*.getBody( String.class )*/ );
        }
    } // Replier

    private static final DefaultCamelContext cc = new DefaultCamelContext();

    public static void main( final String... args ) throws Exception {

        final Replier replier = new RequestReplyMessageSample().new Replier();

        cc.setName( "Request Reply Sample" );
        cc.addRoutes( new RouteBuilder() {

            @Override
            public void configure() {

                from( "timer:start?repeatCount=1" )
                        .setExchangePattern( ExchangePattern.InOut )
                        .process().message( m -> m.setBody( "'Re'quest'" ) ) // EIP Request
                        .process().message( m -> print( "Request", m ) )
                        .log( "Requesting..." )
                        .log( "Replying..." )
                        // How to get Message (or Exchange) as argument in here?
                        .bean( replier, "reply(${body})" ) // EIP Requestor/Replier
                        .process().message( m -> print( "Reply", m ) ) // EIP Reply (in the body of the Message)
                        .setId( "Request/Reply" );
            }
        } );
        cc.start();
        Thread.sleep( 2000 );
        cc.stop();
        cc.close();
    } // main()

    static void print( final String endpoint, final Message m ) {

        out.printf( "%s %s: %s%n", endpoint, m, m.getBody() );
    } // print()

} // RequestReplyMessageSample

输出

...
Request Message: 'Re'quest'
[ple) thread #1 - timer://start] Request/Reply                  INFO  Requesting...
[ple) thread #1 - timer://start] Request/Reply                  INFO  Replying...

[ERROR] Expected: 'Re'quest', Actual: Re'quest  <-- Am I doing somethig wrong, is this a bug or a feature?

Reply Message: **** Replying to Re'quest ****
...

Answer 1

这是一个feature. In this case, the single quotes at the start/end of the expression are interpreted as a string literal start/end。您需要添加另一个单引号让解析器将其视为字符（即 m.setBody("''Re'quest''")）。

Answer 2

这是因为主体作为显式方法参数传递给 bean。

在以下情况下单引号被保留：

在请求中将字符串作为消息正文传递
将路由 (.setBody) 中的正文设置（或覆盖）为常量
将路由 (.setBody) 中的正文设置（或覆盖）为表达式
passing the body implicit to a bean
通过 bean 方法设置（或覆盖）主体 return 值
通过处理器 bean 设置（或覆盖）正文

仅当正文为passed explicitly to a bean method时，引号才被解释为字符串文字边界。

.bean(new EchoBean(), "echoBody(${body})")

成为你的情况

.bean(new EchoBean(), "echoBody('Re'quest')")

您可以尝试这个测试 class（Camel 3、JUnit 5）。它失败了，因为引号在最后一个带有显式参数的 bean 调用中丢失了。

package test.camel;

import org.apache.camel.builder.RouteBuilder;
import org.apache.camel.test.junit5.CamelTestSupport;
import org.junit.jupiter.api.Test;

class QuoteTest extends CamelTestSupport {
    public static final String MOCK_OUTPUT = "mock:output";

    protected RouteBuilder createRouteBuilder() throws Exception {
        return new RouteBuilder() {
            @Override
            public void configure() throws Exception {
                from( "direct:start" )
                        .log("Reveived body: ${body}")
                        .setBody(constant("'Re'quest'"))
                        .log("Body overwritten in route: ${body}")
                        .bean(new EchoBean())
                        .log("Body overwritten through bean: ${body}")
                        .process().message( m -> m.setBody( "'Re'quest'" ) )
                        .log("Body overwritten through processor: ${body}")
                        .bean(new EchoBean(), "echoBody(${body})")
                        .log("Body overwritten through bean with methodparameter: ${body}")
                        .to(MOCK_OUTPUT);
            }
        };
    }

    @Test
    void routeTest_quoteHandling_processed() throws Exception {
        getMockEndpoint(MOCK_OUTPUT).expectedBodiesReceived("'Re'quest'");
        template.requestBody("direct:start", "'Re'quest'");
        assertMockEndpointsSatisfied();
    }

    static class EchoBean {
        public String echoBody(final String messageBody) {
            System.out.println("Expected: 'Re'quest', Actual: " + messageBody);
            return messageBody;
        }
    }
}

它产生以下输出。如您所见，除了最后一个带有显式参数传递的 bean 调用外，所有步骤都保留了引号

09:00:53.521 [main] INFO  route1 - Reveived body: 'Re'quest'
09:00:53.521 [main] INFO  route1 - Body overwritten in route: 'Re'quest'
Expected: 'Re'quest', Actual: 'Re'quest'
09:00:53.527 [main] INFO  route1 - Body overwritten through bean: 'Re'quest'
09:00:53.527 [main] INFO  route1 - Body overwritten through processor: 'Re'quest'
Expected: 'Re'quest', Actual: Re'quest  <<-- only when the body is passed as method parameter, the quotes are lost
09:00:53.529 [main] INFO  route1 - Body overwritten through bean with methodparameter: Re'quest

Apache Camel 从 String 消息正文中删除撇号

Apache Camel trims off apostrophes from String message body

string

javabeans

apache-camel

message-body

输出