相关疑难解决方法(0)

已经发布了几个关于依赖注入的具体问题的问题,例如何时使用它以及它有哪些框架.然而,

什么是依赖注入以及何时/为什么应该或不应该使用它？

我正在阅读spring 3.0.x参考文档以了解Spring Autowired注释:

3.9.2 @Autowired和@Inject

我无法理解下面的例子.我们是否需要在XML中执行某些操作才能使用它？

例1

public class SimpleMovieLister {

    private MovieFinder movieFinder;

    @Autowired
    public void setMovieFinder(MovieFinder movieFinder) {
        this.movieFinder = movieFinder;
    }

    // ...
}

例2

public class MovieRecommender {

    private MovieCatalog movieCatalog;

    private CustomerPreferenceDao customerPreferenceDao;

    @Autowired
    public void prepare(MovieCatalog movieCatalog,
                    CustomerPreferenceDao customerPreferenceDao) {
        this.movieCatalog = movieCatalog;
        this.customerPreferenceDao = customerPreferenceDao;
    }

    // ...
}

如何通过自动装配两个类来实现相同的接口并使用相同的类？

例:

class Red implements Color
class Blue implements Color

class myMainClass{
    @Autowired 
    private Color color;

    draw(){
        color.design(); 
    } 
}

将调用哪种设计方法？如何确保调用Red类的设计方法而不是Blue？

使用过滤器(DelegatingFilterProxy)安装SpringBoot Legacy(web.xml)WAR应用程序时,我收到以下错误/ stacktrace:

java.lang.IllegalStateException:org.springframework.boot.legacy.context.web.AnnotationConfigNonEmbeddedWebApplicationContext@fff88888尚未刷新

提供的日志......

[ERROR] 2016-01-11 11:11:11,265 org.springframework.web.servlet.DispatcherServlet - Context initialization failed
java.lang.IllegalStateException: org.springframework.boot.legacy.context.web.AnnotationConfigNonEmbeddedWebApplicationContext@fff88888 has not been refreshed yet
        at org.springframework.context.support.AbstractApplicationContext.assertBeanFactoryActive(AbstractApplicationContext.java:1041)
        at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1059)
        at org.springframework.web.servlet.DispatcherServlet.initMultipartResolver(DispatcherServlet.java:497)
        at org.springframework.web.servlet.DispatcherServlet.initStrategies(DispatcherServlet.java:479)
        at org.springframework.web.servlet.DispatcherServlet.onRefresh(DispatcherServlet.java:471)
        at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:559)
        at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:493)
        at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:136)
        at javax.servlet.GenericServlet.init(GenericServlet.java:161)
        at com.ibm.ws.webcontainer.servlet.ServletWrapper.init(ServletWrapper.java:342)
        at com.ibm.ws.webcontainer.servlet.ServletWrapperImpl.init(ServletWrapperImpl.java:168)
        at com.ibm.ws.webcontainer.servlet.ServletWrapper.load(ServletWrapper.java:1375)
        at com.ibm.ws.webcontainer.filter.WebAppFilterManager.invokeFilters(WebAppFilterManager.java:1024)
        at com.ibm.ws.webcontainer.webapp.WebApp.handleRequest(WebApp.java:3815)
        at com.ibm.ws.webcontainer.webapp.WebGroup.handleRequest(WebGroup.java:304)
        at com.ibm.ws.webcontainer.WebContainer.handleRequest(WebContainer.java:981)
        at com.ibm.ws.webcontainer.WSWebContainer.handleRequest(WSWebContainer.java:1662)
        at com.ibm.ws.webcontainer.channel.WCChannelLink.ready(WCChannelLink.java:200)
        at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleDiscrimination(HttpInboundLink.java:456)
        at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleNewRequest(HttpInboundLink.java:518)
        at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.processRequest(HttpInboundLink.java:309)
        at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.ready(HttpInboundLink.java:280)
        at com.ibm.ws.ssl.channel.impl.SSLConnectionLink.determineNextChannel(SSLConnectionLink.java:1049)
        at com.ibm.ws.ssl.channel.impl.SSLConnectionLink$MyReadCompletedCallback.complete(SSLConnectionLink.java:643)
        at com.ibm.ws.ssl.channel.impl.SSLReadServiceContext$SSLReadCompletedCallback.complete(SSLReadServiceContext.java:1818)
        at com.ibm.ws.tcp.channel.impl.AioReadCompletionListener.futureCompleted(AioReadCompletionListener.java:175)
        at com.ibm.io.async.AbstractAsyncFuture.invokeCallback(AbstractAsyncFuture.java:217)
        at com.ibm.io.async.AsyncChannelFuture.fireCompletionActions(AsyncChannelFuture.java:161)
        at com.ibm.io.async.AsyncFuture.completed(AsyncFuture.java:138)
        at com.ibm.io.async.ResultHandler.complete(ResultHandler.java:204) …