Luca Burgazzoli created CAMEL-10548:
---------------------------------------
Summary: Converter from List to String is not found when
@EnableAutoConfiguration is used
Key: CAMEL-10548
URL: https://issues.apache.org/jira/browse/CAMEL-10548
Project: Camel
Issue Type: Bug
Components: camel-spring-boot
Reporter: Luca Burgazzoli
Assignee: Luca Burgazzoli
Fix For: 2.19.0
This very simple spring-boot application :
{code:java}
@SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
@Component
public class MyRouteBuilder extends RouteBuilder {
@Override
public void configure() throws Exception {
from("timer:person")
.setBody().constant(Arrays.asList(
new Person("Peter", 25),
new Person("John", 33)
))
.log("Body is ${body}");
}
}
public static class Person {
private String name;
private int age;
public Person(String name, int age) {
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "Person{" +
"name='" + name + '\'' +
", age=" + age +
'}';
}
}
}
{code}
Fails to resolve the simple expression ${body} because of the following
exception:
{code}
org.apache.camel.TypeConversionException: Error during type conversion from
type: java.lang.String to the required type: java.lang.String with value
[Person{name='Peter', age=25}, Person{name='John', age=33}] due Failed to
convert from type [java.util.Arrays$ArrayList<?>] to type [java.lang.String]
for value '[Person{name='Peter', age=25}, Person{name='John', age=33}]'; nested
exception is org.springframework.core.convert.ConverterNotFoundException: No
converter found capable of converting from type [java.util.Arrays$ArrayList<?>]
to type [java.lang.String]
at
org.apache.camel.impl.converter.BaseTypeConverterRegistry.createTypeConversionException(BaseTypeConverterRegistry.java:629)
~[camel-core-2.18.0.jar:2.18.0]
at
org.apache.camel.impl.converter.BaseTypeConverterRegistry.convertTo(BaseTypeConverterRegistry.java:150)
~[camel-core-2.18.0.jar:2.18.0]
at
org.apache.camel.support.ExpressionAdapter.evaluate(ExpressionAdapter.java:41)
~[camel-core-2.18.0.jar:2.18.0]
at
org.apache.camel.builder.ExpressionBuilder$75.evaluate(ExpressionBuilder.java:1795)
~[camel-core-2.18.0.jar:2.18.0]
at
org.apache.camel.support.ExpressionAdapter.evaluate(ExpressionAdapter.java:36)
~[camel-core-2.18.0.jar:2.18.0]
at
org.apache.camel.processor.LogProcessor.process(LogProcessor.java:53)
~[camel-core-2.18.0.jar:2.18.0]
at
org.apache.camel.management.InstrumentationProcessor.process(InstrumentationProcessor.java:77)
~[camel-core-2.18.0.jar:2.18.0]
at
org.apache.camel.processor.RedeliveryErrorHandler.process(RedeliveryErrorHandler.java:542)
~[camel-core-2.18.0.jar:2.18.0]
at
org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:197)
[camel-core-2.18.0.jar:2.18.0]
at org.apache.camel.processor.Pipeline.process(Pipeline.java:120)
~[camel-core-2.18.0.jar:2.18.0]
at org.apache.camel.processor.Pipeline.process(Pipeline.java:83)
~[camel-core-2.18.0.jar:2.18.0]
at
org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:197)
[camel-core-2.18.0.jar:2.18.0]
at
org.apache.camel.component.timer.TimerConsumer.sendTimerExchange(TimerConsumer.java:192)
[camel-core-2.18.0.jar:2.18.0]
at
org.apache.camel.component.timer.TimerConsumer$1.run(TimerConsumer.java:76)
[camel-core-2.18.0.jar:2.18.0]
at java.util.TimerThread.mainLoop(Timer.java:555) [na:1.8.0_112]
at java.util.TimerThread.run(Timer.java:505) [na:1.8.0_112]
Caused by: org.springframework.core.convert.ConversionFailedException: Failed
to convert from type [java.util.Arrays$ArrayList<?>] to type [java.lang.String]
for value '[Person{name='Peter', age=25}, Person{name='John', age=33}]'; nested
exception is org.springframework.core.convert.ConverterNotFoundException: No
converter found capable of converting from type [java.util.Arrays$ArrayList<?>]
to type [java.lang.String]
at
org.springframework.core.convert.support.ConversionUtils.invokeConverter(ConversionUtils.java:42)
~[spring-core-4.3.3.RELEASE.jar:4.3.3.RELEASE]
at
org.springframework.core.convert.support.GenericConversionService.convert(GenericConversionService.java:192)
~[spring-core-4.3.3.RELEASE.jar:4.3.3.RELEASE]
at
org.springframework.core.convert.support.GenericConversionService.convert(GenericConversionService.java:176)
~[spring-core-4.3.3.RELEASE.jar:4.3.3.RELEASE]
at
org.apache.camel.spring.boot.SpringTypeConverter.convertTo(SpringTypeConverter.java:46)
~[camel-spring-boot-2.18.0.jar:2.18.0]
at
org.apache.camel.impl.converter.BaseTypeConverterRegistry.doConvertTo(BaseTypeConverterRegistry.java:346)
~[camel-core-2.18.0.jar:2.18.0]
at
org.apache.camel.impl.converter.BaseTypeConverterRegistry.convertTo(BaseTypeConverterRegistry.java:133)
~[camel-core-2.18.0.jar:2.18.0]
... 14 common frames omitted
Caused by: org.springframework.core.convert.ConverterNotFoundException: No
converter found capable of converting from type [java.util.Arrays$ArrayList<?>]
to type [java.lang.String]
at
org.springframework.core.convert.support.GenericConversionService.handleConverterNotFound(GenericConversionService.java:313)
~[spring-core-4.3.3.RELEASE.jar:4.3.3.RELEASE]
at
org.springframework.core.convert.support.GenericConversionService.convert(GenericConversionService.java:195)
~[spring-core-4.3.3.RELEASE.jar:4.3.3.RELEASE]
at
org.springframework.core.convert.support.CollectionToStringConverter.convert(CollectionToStringConverter.java:68)
~[spring-core-4.3.3.RELEASE.jar:4.3.3.RELEASE]
at
org.springframework.core.convert.support.ConversionUtils.invokeConverter(ConversionUtils.java:36)
~[spring-core-4.3.3.RELEASE.jar:4.3.3.RELEASE]
... 19 common frames omitted
{code}
The root cause is spring failing to find a converter for Person --> String and
as the SpringTypeConverter registered by camel-spring-boot is one of the
fallback converters used by BaseTypeConverterRegistry, it leads Camel to fail
too.
As today is a Camel TypeConverter fails with an exception while looping over
fallback converters, the loops ends and the conversion fails too. It may turn
out that the bug is caused by the way camel uses Spring's type converters but
it may be good to catch exceptions and try the next converter, [~davsclaus]
make sense ?
A workaround is to create a custom converter for the class:
{code:java}
@Component
public class PersonConverter implements Converter<Person, String> {
@Override
public String convert(Person source) {
return source.toString();
}
}
{code}
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