我想以这种方式注入配置参数：
public class MyManagedBean {
@Inject
public MyManagedBean(@Named("user") String user){
....
}
}
所以我尝试这样实现生产者方法：
@ApplicationScoped
public class MyConfiguration {
private Properties loadProperties() {
Properties properties = new Properties();
try {
properties.load(getClass().getResourceAsStream(
"user.properties"));
} catch (IOException e) {
throw new RuntimeException();
}
return properties;
}
@Produces
@Named("user")
String getUser() {
return loadProperties().getProperty("user");
}
}
我还有这样定义的其他 bean：
public class OtherManagedBean {
@Inject
public OtherManagedBean(MyManagedBean myManagedBean){
....
}
}
但是，当我尝试部署它时遇到此异常：
INFO: WEB0671: Loading application [example-ear#example-war.war] at [example]
SEVERE: Exception while loading the app
SEVERE: Exception while loading the app : WELD-001410 The injection point [parameter 1] of [constructor] @Inject public com.example.OtherManagedBean(MyManagedBean) has non-proxyable dependencies
org.jboss.weld.exceptions.UnproxyableResolutionException: WELD-001410 The injection point [parameter 1] of [constructor] @Inject public com.example.OtherManagedBean(MyManagedBean) has non-proxyable dependencies
at org.jboss.weld.bootstrap.Validator.validateInjectionPoint(Validator.java:317)
at org.jboss.weld.bootstrap.Validator.validateBean(Validator.java:139)
at org.jboss.weld.bootstrap.Validator.validateRIBean(Validator.java:162)
at org.jboss.weld.bootstrap.Validator.validateBeans(Validator.java:385)
at org.jboss.weld.bootstrap.Validator.validateDeployment(Validator.java:371)
at org.jboss.weld.bootstrap.WeldBootstrap.validateBeans(WeldBootstrap.java:390)
at org.glassfish.weld.WeldDeployer.event(WeldDeployer.java:190)
at org.glassfish.kernel.event.EventsImpl.send(EventsImpl.java:128)
at org.glassfish.internal.data.ApplicationInfo.start(ApplicationInfo.java:298)
at com.sun.enterprise.v3.server.ApplicationLifecycle.deploy(ApplicationLifecycle.java:461)
at com.sun.enterprise.v3.server.ApplicationLifecycle.deploy(ApplicationLifecycle.java:240)
at org.glassfish.deployment.admin.DeployCommand.execute(DeployCommand.java:370)
at com.sun.enterprise.v3.admin.CommandRunnerImpl$1.execute(CommandRunnerImpl.java:355)
at com.sun.enterprise.v3.admin.CommandRunnerImpl.doCommand(CommandRunnerImpl.java:370)
at com.sun.enterprise.v3.admin.CommandRunnerImpl.doCommand(CommandRunnerImpl.java:1067)
at com.sun.enterprise.v3.admin.CommandRunnerImpl.access$1200(CommandRunnerImpl.java:96)
at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1247)
at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1235)
at com.sun.enterprise.v3.admin.AdminAdapter.doCommand(AdminAdapter.java:465)
at com.sun.enterprise.v3.admin.AdminAdapter.service(AdminAdapter.java:222)
at com.sun.grizzly.tcp.http11.GrizzlyAdapter.service(GrizzlyAdapter.java:168)
at com.sun.enterprise.v3.server.HK2Dispatcher.dispath(HK2Dispatcher.java:117)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:234)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:822)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:719)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1013)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:225)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
at java.lang.Thread.run(Thread.java:662)
任何想法？
Thanks.
It looks like you need a default (no-arg) constructor for your MyManagedBean to make it proxyable. I am not really sure about why it is needed, since MyManagedBean is a @Dependent bean and so is not proxied AFAIK; I do not know even why a proxyable bean needs a default constructor, to be honest This seems to be an implementation detail or a little point from CDI specification that was ignored. Anyway, I bet it can make a good new question :)
EDIT：我发现了为什么可代理 bean 需要默认构造函数。实际上，这并不神秘：由于 bean 的代理是同一 bean 的子类，因此代理需要调用super()构造函数在它自己的构造中。如果它没有非私有默认构造函数，则它不知道要调用哪个构造函数。人们甚至可以想象这样一种场景：调用注入的构造函数来创建代理，但我不知道它会给 CDI 实现增加哪种复杂性；可能没那么容易做到...
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