“春季MVC”；找不到能够从java.lang.String类型转换为org.springframework.core.io.Resource类型的转换器；

我们有许多自定义的“org.springframework.core.convert.converter.converter”转换器，可以帮助我们自动将rest请求中的URL参数映射到域对象

今天，我们通过定义转换服务注册了这些转换器：

<bean id="conversionService" class="org.springframework.format.support.FormattingConversionServiceFactoryBean">
    <property name="converters">
        <set>
            <!-- List of custom converter beans here -->
        </set>
    </property>
</bean>

然后使用以下方式进行注册：

<mvc:annotation-driven conversion-service="conversionService" />

但是，对于我们的每个定义，我们在启动时都会遇到以下异常：

org.springframework.core.convert.ConversionFailedException: Failed to convert from type java.util.ArrayList<?> to type java.util.List<org.springframework.core.io.Resource> for value '[/WEB-INF/images/]'; nested exception is org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting from type java.lang.String to type org.springframework.core.io.Resource

org.springframework.core.convert.conversionfailedeexception:无法将值“[/WEB-INF/images/]”的类型java.util.ArrayList转换为类型java.util.List；嵌套异常为org.springframework.core.convert.ConverterNotFoundException：未找到能够从java.lang.String类型转换为org.springframework.core.io.Resource类型的转换器

以前是否有人遇到/解决过此问题

---

我们使用的是spring 3.2.9。

结果是我没有正确读取堆栈跟踪上方的行。。。忽略了堆栈上方的行是“DEBUG”这一事实

简而言之，转换服务无法从字符串转换为资源；然而，spring依赖于它的基于PropertyEditor的转换，该转换成功了（我相信这就是通常进行字符串资源转换的方式）

我创建了一个示例项目，该项目将重新创建此调试异常：

完整堆栈的示例如下所示：

DEBUG: org.springframework.beans.TypeConverterDelegate - Original ConversionService attempt failed - ignored since PropertyEditor based conversion eventually succeeded
org.springframework.core.convert.ConversionFailedException: Failed to convert from type java.util.ArrayList<?> to type java.util.List<org.springframework.core.io.Resource> for value '[/WEB-INF/css/]'; nested exception is org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting from type java.lang.String to type org.springframework.core.io.Resource
    at org.springframework.core.convert.support.ConversionUtils.invokeConverter(ConversionUtils.java:41)
    at org.springframework.core.convert.support.GenericConversionService.convert(GenericConversionService.java:168)
    at org.springframework.beans.TypeConverterDelegate.convertIfNecessary(TypeConverterDelegate.java:161)
    at org.springframework.beans.BeanWrapperImpl.convertIfNecessary(BeanWrapperImpl.java:448)
    at org.springframework.beans.BeanWrapperImpl.convertForProperty(BeanWrapperImpl.java:494)
    at org.springframework.beans.BeanWrapperImpl.convertForProperty(BeanWrapperImpl.java:488)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.convertForProperty(AbstractAutowireCapableBeanFactory.java:1463)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1422)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1158)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:296)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:293)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:633)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
    at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:651)
    at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:602)
    at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:665)
    at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:521)
    at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:462)
    at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:136)
    at javax.servlet.GenericServlet.init(GenericServlet.java:160)
    at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1280)
    at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1193)
    at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1088)
    at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:5198)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5481)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:634)
    at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:671)
    at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1840)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask.run(FutureTask.java:262)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:745)
Caused by: org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting from type java.lang.String to type org.springframework.core.io.Resource
    at org.springframework.core.convert.support.GenericConversionService.handleConverterNotFound(GenericConversionService.java:276)
    at org.springframework.core.convert.support.GenericConversionService.convert(GenericConversionService.java:171)
    at org.springframework.core.convert.support.CollectionToCollectionConverter.convert(CollectionToCollectionConverter.java:83)
    at org.springframework.core.convert.support.ConversionUtils.invokeConverter(ConversionUtils.java:35)
    ... 40 more

DEBUG:org.springframework.beans.TypeConverterDelegate-原始转换服务尝试失败-被忽略，因为基于PropertyEditor的转换最终成功
org.springframework.core.convert.ConversionFailedException:无法将值“[/WEB-INF/css/]”的类型java.util.ArrayList转换为类型java.util.List；嵌套异常为org.springframework.core.convert.ConverterNotFoundException：未找到能够从java.lang.String类型转换为org.springframework.core.io.Resource类型的转换器
位于org.springframework.core.convert.support.ConversionUtils.invokeConverter（ConversionUtils.java:41）
位于org.springframework.core.convert.support.GenericConversionService.convert（GenericConversionService.java:168）
位于org.springframework.beans.TypeConverterDelegate.ConvertifRequired（TypeConverterDelegate.java:161）
在org.springframework.beans.BeanWrapperImpl.convertifRequired上（BeanWrapperImpl.java:448）
位于org.springframework.beans.BeanWrapperImpl.convertForProperty（BeanWrapperImpl.java:494）
位于org.springframework.beans.BeanWrapperImpl.convertForProperty（BeanWrapperImpl.java:488）
位于org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.convertForProperty（AbstractAutowireCapableBeanFactory.java:1463）
位于org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues（AbstractAutowireCapableBeanFactory.java:1422）
位于org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean（AbstractAutowireCapableBeanFactory.java:1158）
位于org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean（AbstractAutowireCapableBeanFactory.java:519）
位于org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean（AbstractAutowireCapableBeanFactory.java:458）
位于org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject（AbstractBeanFactory.java:296）
位于org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton（DefaultSingletonBeanRegistry.java:223）
位于org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean（AbstractBeanFactory.java:293）
位于org.springframework.beans.factory.support.AbstractBeanFactory.getBean（AbstractBeanFactory.java:194）
位于org.springframework.beans.factory.support.DefaultListableBeanFactory.PreInstanceSingleton（DefaultListableBeanFactory.java:633）
位于org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization（AbstractApplicationContext.java:932）
位于org.springframework.context.support.AbstractApplicationContext.refresh（AbstractApplicationContext.java:479）
位于org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext（FrameworkServlet.java:651）
位于org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext（FrameworkServlet.java:602）
位于org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext（FrameworkServlet.java:665）
位于org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext（FrameworkServlet.java:521）
位于org.springframework.web.servlet.FrameworkServlet.initServletBean（FrameworkServlet.java:462）
位于org.springframework.web.servlet.HttpServletBean.init（HttpServletBean.java:136）
位于javax.servlet.GenericServlet.init（GenericServlet.java:160）
位于org.apache.catalina.core.StandardWrapper.initServlet（StandardWrapper.java:1280）
位于org.apache.catalina.core.StandardWrapper.loadServlet（StandardWrapper.java:1193）
位于org.apache.catalina.core.StandardWrapper.load（StandardWrapper.java:1088）
位于org.apache.catalina.core.StandardContext.loadOnStartup（StandardContext.java:5198）
位于org.apache.catalina.core.StandardContext.startInternal（StandardContext.java:5481）
位于org.apache.catalina.util.LifecycleBase.start（LifecycleBase.java:150）
位于org.apache.catalina.core.ContainerBase.addChildInternal（ContainerBase.java:901）
位于org.apache.catalina.core.ContainerBase.addChild（ContainerBase.java:877）
位于org.apache.catalina.core.StandardHost.addChild（StandardHost.java:634）
位于org.apache.catalina.startup.HostConfig.deployDescriptor（HostConfig.java:671）
位于org.apache.catalina.startup.HostConfig$DeployDescriptor.run（HostConfig.java:1840）
位于java.util.concurrent.Executors$RunnableAdapter.call（Executors.java:471）
在j
<logger name="org.springframework.beans.TypeConverterDelegate">
    <level value="error" />
</logger>

<bean id="conversionService" class="org.springframework.format.support.FormattingConversionServiceFactoryBean">
    <property name="registerDefaultFormatters" value="false" />
    <property name="converters">
        <set>
            <bean class="com.example.controller.converter.CustomerStringToDateConverter"/>
        </set>
    </property>
</bean>

<mvc:annotation-driven conversion-service="conversionService"/>

<mvc:resources mapping="/js/**" location="/js/" cache-period="31556926"/>

DEBUG [RMI TCP Connection(3)-127.0.0.1] - Original ConversionService attempt failed - ignored since PropertyEditor based conversion eventually succeeded
org.springframework.core.convert.ConversionFailedException: Failed to convert from type java.util.ArrayList<?> to type java.util.List<org.springframework.core.io.Resource> for value '[/js/]'; nested exception is org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting from type java.util.ArrayList<?> to type org.springframework.core.io.Resource

<mvc:annotation-driven conversion-service="conversionService"/>