我正在使用Spring Java配置并使用一些Camel路由编写控制台应用程序。我的应用程序中有几个属性源，所以我使用两个PropertyPlaceholderConfigurers：
@Configuration
@Import(CamelConfig.class)
@ComponentScan(basePackageClasses = {App.class})
public class Config
{
final static String ENV = System.getProperty( "ENV" );
@Bean
public static BridgePropertyPlaceholderConfigurer properties()
{
final BridgePropertyPlaceholderConfigurer result = new BridgePropertyPlaceholderConfigurer();
result.setOrder( 0 );
result.setIgnoreUnresolvablePlaceholders( true );
result.setLocations( new ClassPathResource( "a/b/c/environments/base.properties" ),
new ClassPathResource( "a/b/c/environments/" + ENV + "/env.properties" ) );
return result;
}
@Bean
public static BridgePropertyPlaceholderConfigurer dlqAppProperties()
{
final YamlPropertiesFactoryBean yaml = new YamlPropertiesFactoryBean();
final BridgePropertyPlaceholderConfigurer result = new BridgePropertyPlaceholderConfigurer();
yaml.setResources( new ClassPathResource( "app.yaml" ) );
result.setOrder( 1 );
result.setIgnoreUnresolvablePlaceholders( true );
result.setProperties( yaml.getObject() );
return result;
}
}
根据this doc，我使用BridgePropertyPlaceholderConfigurer类在Camel中提供Spring属性。它的配置也很简单：
@Configuration
public class CamelConfig extends SingleRouteCamelConfiguration
{
@Override
protected CamelContext createCamelContext() throws Exception
{
final SpringCamelContext result = new SpringCamelContext( getApplicationContext() );
return result;
}
@Override
protected void setupCamelContext( CamelContext camelContext ) throws Exception
{
}
@Bean
@Override
public RouteBuilder route()
{
return (new Routes()).builder();
}
}
测试路线（Scala DSL）也很简单：
class Routes extends RouteBuilder {
"timer://{{foo}}?period=2s" ==> {
process((exchange) => {
exchange.getIn.setBody("test")
})
to("log:test")
}
}
但是上下文不是从以下异常开始的：
Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'camelContext' defined in class path resource [a/b/c/config/CamelConfig.class]: Invocation of init method failed; nested exception is org.apache.camel.FailedToCreateRouteException: Failed to create route route1: Route(route1)[[From[timer://{{foo}}?period=2s]] -> [process[... because of Failed to resolve endpoint: timer://{{foo}}?period=2s due to: PropertiesComponent with name properties must be defined in CamelContext to support property placeholders.
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1566)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:539)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:303)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:299)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:755)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:757)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480)
at org.springframework.context.annotation.AnnotationConfigApplicationContext.<init>(AnnotationConfigApplicationContext.java:84)
at a.b.c.App.main(App.java:13)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134)
Caused by: org.apache.camel.FailedToCreateRouteException: Failed to create route route1: Route(route1)[[From[timer://{{foo}}?period=2s]] -> [process[... because of Failed to resolve endpoint: timer://{{foo}}?period=2s due to: PropertiesComponent with name properties must be defined in CamelContext to support property placeholders.
at org.apache.camel.model.RouteDefinition.addRoutes(RouteDefinition.java:182)
at org.apache.camel.impl.DefaultCamelContext.startRoute(DefaultCamelContext.java:770)
at org.apache.camel.impl.DefaultCamelContext.startRouteDefinitions(DefaultCamelContext.java:1914)
at org.apache.camel.impl.DefaultCamelContext.doStartCamel(DefaultCamelContext.java:1670)
at org.apache.camel.impl.DefaultCamelContext.doStart(DefaultCamelContext.java:1544)
at org.apache.camel.spring.SpringCamelContext.doStart(SpringCamelContext.java:179)
at org.apache.camel.support.ServiceSupport.start(ServiceSupport.java:61)
at org.apache.camel.impl.DefaultCamelContext.start(DefaultCamelContext.java:1512)
at org.apache.camel.spring.SpringCamelContext.maybeStart(SpringCamelContext.java:228)
at org.apache.camel.spring.SpringCamelContext.afterPropertiesSet(SpringCamelContext.java:104)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1625)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1562)
... 16 more
Caused by: org.apache.camel.ResolveEndpointFailedException: Failed to resolve endpoint: timer://{{foo}}?period=2s due to: PropertiesComponent with name properties must be defined in CamelContext to support property placeholders.
at org.apache.camel.impl.DefaultCamelContext.getEndpoint(DefaultCamelContext.java:477)
at org.apache.camel.util.CamelContextHelper.getMandatoryEndpoint(CamelContextHelper.java:63)
at org.apache.camel.model.RouteDefinition.resolveEndpoint(RouteDefinition.java:192)
at org.apache.camel.impl.DefaultRouteContext.resolveEndpoint(DefaultRouteContext.java:106)
at org.apache.camel.impl.DefaultRouteContext.resolveEndpoint(DefaultRouteContext.java:112)
at org.apache.camel.model.FromDefinition.resolveEndpoint(FromDefinition.java:72)
at org.apache.camel.impl.DefaultRouteContext.getEndpoint(DefaultRouteContext.java:88)
at org.apache.camel.model.RouteDefinition.addRoutes(RouteDefinition.java:890)
at org.apache.camel.model.RouteDefinition.addRoutes(RouteDefinition.java:177)
... 27 more
Caused by: java.lang.IllegalArgumentException: PropertiesComponent with name properties must be defined in CamelContext to support property placeholders.
at org.apache.camel.impl.DefaultCamelContext.resolvePropertyPlaceholders(DefaultCamelContext.java:1121)
at org.apache.camel.impl.DefaultCamelContext.getEndpoint(DefaultCamelContext.java:475)
... 35 more
看起来这个桥不起作用（但我绝对可以在Spring中使用占位符）。可能是什么问题？
看起来如果你想使用BridgePropertyPlaceholderConfigurer，你需要用CamelContextFactoryBean实例化Camel上下文。它有initPropertyPlaceholder方法：
@Override
protected void initPropertyPlaceholder() throws Exception {
super.initPropertyPlaceholder();
Map<String, BridgePropertyPlaceholderConfigurer> beans = applicationContext.getBeansOfType(BridgePropertyPlaceholderConfigurer.class);
if (beans.size() == 1) {
// setup properties component that uses this beans
BridgePropertyPlaceholderConfigurer configurer = beans.values().iterator().next();
String id = beans.keySet().iterator().next();
LOG.info("Bridging Camel and Spring property placeholder configurer with id: " + id);
// get properties component
PropertiesComponent pc = getContext().getComponent("properties", PropertiesComponent.class);
// replace existing resolver with us
configurer.setResolver(pc.getPropertiesResolver());
configurer.setParser(pc.getPropertiesParser());
String ref = "ref:" + id;
// use the bridge to handle the resolve and parsing
pc.setPropertiesResolver(configurer);
pc.setPropertiesParser(configurer);
// and update locations to have our as ref first
String[] locations = pc.getLocations();
String[] updatedLocations;
if (locations != null && locations.length > 0) {
updatedLocations = new String[locations.length + 1];
updatedLocations[0] = ref;
System.arraycopy(locations, 0, updatedLocations, 1, locations.length);
} else {
updatedLocations = new String[]{ref};
}
pc.setLocations(updatedLocations);
} else if (beans.size() > 1) {
LOG.warn("Cannot bridge Camel and Spring property placeholders, as exact only 1 bean of type BridgePropertyPlaceholderConfigurer"
+ " must be defined, was {} beans defined.", beans.size());
}
}
嗯，现在的问题是有两座桥梁，但这是另一个故事......
我有同样的问题。这对我有用（灵感来自initPropertyPlaceholder()方法）：
import org.apache.camel.component.properties.PropertiesComponent;
import org.apache.camel.spring.javaconfig.CamelConfiguration;
import org.apache.camel.spring.spi.BridgePropertyPlaceholderConfigurer;
@Configuration
@ComponentScan
public class AwesomeConfig extends CamelConfiguration {
private static final String PROPERTIES_BEAN_NAME = "springProperties";
@Resource(name = PROPERTIES_BEAN_NAME)
private BridgePropertyPlaceholderConfigurer springProperties;
@Bean(PROPERTIES_BEAN_NAME)
public static BridgePropertyPlaceholderConfigurer springProperties() throws Exception {
BridgePropertyPlaceholderConfigurer configurer = new BridgePropertyPlaceholderConfigurer();
configurer.setSystemPropertiesMode(BridgePropertyPlaceholderConfigurer.SYSTEM_PROPERTIES_MODE_OVERRIDE);
String defaultPropertiesPath = buildProperties().getProperty("properties.path");
String propertiesPath = System.getProperty(PROPERTY_FILE_SYSTEM_PROPERTY, defaultPropertiesPath);
configurer.setLocations(new ClassPathResource("META-INF/application.properties"));
return configurer;
}
@Bean
public PropertiesComponent camelProperties() throws Exception {
PropertiesComponent camelProperties = new PropertiesComponent();
springProperties.setParser(camelProperties.getPropertiesParser());
springProperties.setResolver(camelProperties.getPropertiesResolver());
camelProperties.setSystemPropertiesMode(springProperties.getSystemPropertiesMode());
camelProperties.setPropertiesResolver(springProperties);
camelProperties.setPropertiesParser(springProperties);
camelProperties.setLocation("ref:" + PROPERTIES_BEAN_NAME);
return camelProperties;
}
@Override
protected void setupCamelContext(CamelContext camelContext) throws Exception {
camelContext.addComponent("properties", camelProperties());
}
}
以下是我如何使用它：
import org.apache.camel.spring.javaconfig.Main;
public class AwesomeMain extends Main {
setConfigClass(AwesomeConfig.class);
}
public static void main(String... args) throws Exception {
AwesomeMain main = new AwesomeMain();
instance = main;
main.run(args);
}
尝试重命名您的第一个BridgePropertyPlaceholderConfigurer bean（在您的情况下方法的名称）。
看看我搞砸了什么。尚未完全测试但想分享;应该使用Spring 5.x.基本上将所有Environment复制到Camel的properties，所以我根本不使用Camel的“桥”。我今天不确定的一件事，如果我必须把它放入“初始”或“重叠”属性：
@Configuration
public static class CamelConfig extends CamelConfiguration {
@Autowired
private ConfigurableEnvironment environment;
@Bean
... some beans ...
//@Bean -- haven't yet found out if we need it as a bean ...
private PropertiesComponent camelProperties() throws Exception {
PropertiesComponent camelProperties = new PropertiesComponent();
// just brutally copy all the properties form environment
HashSet<String> propertyNames = new HashSet<String>(100);
for (PropertySource ps : environment.getPropertySources()) {
if (ps instanceof MapPropertySource) {
MapPropertySource mps = (MapPropertySource) ps;
propertyNames.addAll(Arrays.asList(mps.getPropertyNames()));
}
}
Properties allProps = new Properties();
for (String prop : propertyNames) {
allProps.setProperty(prop, environment.getProperty(prop));
}
camelProperties.setInitialProperties(allProps);
// TODO: check it this is better or worse
//camelProperties.setOverrideProperties(allProps);
return camelProperties;
}
@Override
protected void setupCamelContext(CamelContext camelContext) throws Exception {
... some configs. ...
camelContext.addComponent("properties", camelProperties());
}
}