Passed-in Resource [resource loaded through InputStream] contains an open stream:cannot determine

Passed-in Resource [resource loaded through InputStream] contains an open stream2009-09-29 11:58 org.springframework.beans.factory.BeanDefinitionStoreException: Passed-in Resource [resource loaded through InputStream] contains an open stream:
cannot determine validation mode automatically. Either pass in a Resource that is able to create fresh streams, or explicitly specify the validationMode on your XmlBeanDefinitionReader instance.

at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.detectValidationMode(XmlBeanDefinitionReader.java:418)

at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.getValidationModeForResource(XmlBeanDefinitionReader.java:400)

at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadBeanDefinitions(XmlBeanDefinitionReader.java:360)

at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:313)

at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:290)

at org.springframework.beans.factory.xml.XmlBeanFactory.<init>(XmlBeanFactory.java:73)

at org.springframework.beans.factory.xml.XmlBeanFactory.<init>(XmlBeanFactory.java:61)

at com.spring.unit1.TestMain.main(TestMain.java:31)

Exception in thread "main" java.lang.NullPointerException

at com.spring.unit1.TestMain.main(TestMain.java:40)

今天开始正式学习Spring，从《Spring in Action》开始，虽然版本老了一些，但是关键是思想，在做第一个练习的时候，原书中代码如下：

BeanFactory factory = new XmlBeanFactory(new FileInputStream("hello.xml"));

可是在2.0以后的版本中，XmlBeanFactory已经被修改；查阅了API发现构造方法的参数修改为Resource类型

查看了一下InputStreamResource 就是Resource接口的实现类；

于是：

   File file = new File("D:/eclipse/workSpace/aSpringDemo/src/hello.xml");

    InputStream is = new FileInputStream(file);

    InputStreamResource isr = new InputStreamResource(is);

    bf = new XmlBeanFactory(isr);

但是却出了上边的异常；

查看源码发现：

reader.loadBeanDefinitions(resource);方法会调用如下代码：

protected int detectValidationMode(Resource resource)

    {

        InputStream inputStream;

        IOException ex;

        if(resource.isOpen())

            throw new BeanDefinitionStoreException("Passed-in Resource [" + resource + "] contains an open stream: " + "cannot determine validation mode automatically. Either pass in a Resource " + "that is able to create fresh streams, or explicitly specify
the validationMode " + "on your XmlBeanDefinitionReader instance.");

再次查看InputStreamResource API：

implementation for a given InputStream. Should only be used if no specific Resource implementation is applicable. In particular, prefer or any of the file-based Resource implementations where possible.

In contrast to other Resource implementations, this is a descriptor for an already opened resource - therefore returning "true" from 

isOpen()

. Do not use it if you need to keep the resource descriptor somewhere, or if you need to read a stream
multiple times.

显然  

public boolean isOpen()

    {

        return true;

    }

于是，使用其他Resource实现类替换比如FileSystemResource，一切OK

例：

File file = new File("F:/java web2.0/javawebProject/SpringApp/src/spring-beans.xml");

FileSystemResource fsr = new FileSystemResource(file);

XmlBeanFactory factory = new XmlBeanFactory(fsr);

在API中，关于InputStreamResource有这样一段描述：它只有在没有其他合适的Resource实现时才使用。而且，只要有可能就尽量使用ByteArrayResource或者其他基于文件的Resource实现。

与其他Resource实现不同的是，这是个 已经 打开资源的描述符-因此isOpen()方法返回true。如果你需要在其他位置保持这个资源的描述符或者多次读取一个流，请不要使用它。

收藏于 2010-11-15