Java 使用CDI注入命名字符串

我希望以这种方式注入配置参数：

public class MyManagedBean {
    @Inject
    public MyManagedBean(@Named("user") String user){
        ....

    }
}

@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");
    }
}

public class OtherManagedBean {
    @Inject
    public OtherManagedBean(MyManagedBean myManagedBean){
        ....

    }
}

因此，我尝试以这种方式实现生产者方法：

public class MyManagedBean {
    @Inject
    public MyManagedBean(@Named("user") String user){
        ....

    }
}

@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");
    }
}

public class OtherManagedBean {
    @Inject
    public OtherManagedBean(MyManagedBean myManagedBean){
        ....

    }
}

我用这种方式定义了其他bean：

public class MyManagedBean {
    @Inject
    public MyManagedBean(@Named("user") String user){
        ....

    }
}

@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");
    }
}

public class OtherManagedBean {
    @Inject
    public OtherManagedBean(MyManagedBean myManagedBean){
        ....

    }
}

但是，当我尝试部署它时，出现了以下异常：

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)

有什么想法吗

谢谢。

您的

MyManagedBean

似乎需要一个代理。我真的不知道为什么需要它，因为

MyManagedBean

是一个

@依赖的

bean，所以它不是AFAIK的代理；我甚至不知道为什么可代理bean需要一个默认构造函数，老实说，这似乎是一个实现细节，或者是CDI规范中被忽略的一点。无论如何，我打赌这会是一个很好的新问题：）

---

编辑：我发现了可代理bean需要默认构造的原因。事实上，这一点并不含糊：由于bean的代理是同一bean的子类，因此代理需要在其自身构造中调用

super（）

构造函数。如果它没有非私有的默认构造函数，它就不知道调用哪个构造函数。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；这可能不太容易……

谢谢，我真的忘了。然而，现在我有另一个问题。。。