Question

我想在Spring应用程序中执行文件I / O.

我进入了XML路径，但一旦运行，我得到的只是BeanCreationException错误。

我在file-locations.properties中创建了my_spring_app/src/main/resources，其内容如下：

# location of desired files

dir.server=/home/user/webapps/my_spring_app/WEB-INF/classes/
dir.local=D:/resources

他们说要修改application-context.xml文件将被声明的.properties，以便Spring可以识别它（???）。
```
<context:property-placeholder location="classpath*:file-locations.properties" properties-ref="filePathProps" />
```
调用.properties图层中的Service文件进行文件I / O.
```
@Value("#{filePathProps.dir.local}")
private String PATH_FILES;

System.out.println(PATH_FILES); // so far null
```
我尝试了多种组合：@Value("#{filePathProps.dir.local}")，@Value("${filePathProps.dir.local}")，@Value("#{dir.local}")，@Value("${dir.local}")，所有这些组合都返回了错误。
我会将BufferedReader和BufferedWriter用于这些文件。

完整的`application-context。

<beans xmlns="http://www.springframework.org/schema/beans"
  xmlns:context="http://www.springframework.org/schema/context"
  xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns:tx="http://www.springframework.org/schema/tx" xmlns:util="http://www.springframework.org/schema/util"
  xsi:schemaLocation="
    http://www.springframework.org/schema/beans     
    http://www.springframework.org/schema/beans/spring-beans-3.2.5xsd
    http://www.springframework.org/schema/context 
    http://www.springframework.org/schema/context/spring-context-3.2.5.xsd
    http://www.springframework.org/schema/mvc
    http://www.springframework.org/schema/mvc/spring-mvc-3.2.5.xsd
    http://www.springframework.org/schema/util   
    http://www.springframework.org/schema/util/spring-util.xsd">

  <!-- Auto-detect components -->

  <context:component-scan base-package="my.spring.app" />

  <bean id="MyService1"
    class="my.spring.app.service.impl.MyService1Impl" />
  <bean id="MyService2Service"
    class="my.spring.app.service.impl.MyService2ServiceImpl" />
  <bean id="MyService3Service"
    class="my.spring.app.service.impl.MyService3ServiceImpl" />

  <mvc:annotation-driven />

  <!-- Application Message Bundle -->
  <bean id="messageSource"
    class="org.springframework.context.support.ReloadableResourceBundleMessageSource">
    <property name="basename" value="/WEB-INF/messages" />
    <property name="cacheSeconds" value="3000" />
  </bean>

  <!-- files??? -->
  <context:property-placeholder location="classpath*:file-locations.properties"
    properties-ref="filePathProps" />

</beans>

以下是web.xml文件：

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_3_1.xsd"
  id="WebApp_ID" version="3.0">

  <display-name>my_spring_app</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>

  <servlet>
    <servlet-name>spring</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet
    </servlet-class>
    <load-on-startup>1</load-on-startup>
  </servlet>

  <servlet-mapping>
    <servlet-name>spring</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>

  <!-- Error pages -->
  <location>/WEB-INF/jsp/error/400.jsp</location>
  <error-page>
    <error-code>400</error-code>
  </error-page>

  <error-page>
    <error-code>403</error-code>
    <location>/WEB-INF/jsp/error/403.jsp</location>
  </error-page>

  <error-page>
    <error-code>404</error-code>
    <location>/WEB-INF/jsp/error/404.jsp</location>
  </error-page>

  <error-page>
    <error-code>405</error-code>
    <location>/WEB-INF/jsp/error/405.jsp</location>
  </error-page>

  <error-page>
    <error-code>500</error-code>
    <location>/WEB-INF/jsp/error/500.jsp</location>
  </error-page>

  <error-page>
    <exception-type>java.lang.Exception</exception-type>
    <location>/WEB-INF/jsp/error/exception.jsp</location>
  </error-page>

</web-app>

以下是spring-servlet.xml文件：

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
  xmlns:context="http://www.springframework.org/schema/context"
  xmlns:mvc="http://www.springframework.org/schema/mvc"
  xsi:schemaLocation="http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd 
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context-3.0.xsd
    http://www.springframework.org/schema/mvc 
    http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">

  <context:component-scan base-package="my.package.controller" />
  <context:component-scan base-package="my.package.service" />

  <bean id="viewResolver"
    class="org.springframework.web.servlet.view.UrlBasedViewResolver">
    <property name="viewClass"
      value="org.springframework.web.servlet.view.JstlView" />
    <property name="prefix" value="/WEB-INF/jsp/" />
    <property name="suffix" value=".jsp" />
  </bean>

  <!--This tag allows for mapping the DispatcherServlet to "/" (all extensions 
    etc) -->
  <mvc:default-servlet-handler />

  <mvc:annotation-driven />
  <mvc:resources location="/resources/**, classpath:resources"
    mapping="/resources/**" />
  <mvc:resources mapping="/css/**" location="/resources/css/*" />
  <mvc:resources mapping="/js/**" location="/resources/js/*" />
  <mvc:resources mapping="/images/**" location="/resources/images/*" />
  <mvc:resources mapping="/weka/**" location="/resources/weka/*" />

</beans>

部分堆栈跟踪（full here）：

org.springframework.web.servlet.DispatcherServlet initServletBean
SEVERE: Context initialization failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'myService': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private my.package.service.CalcService my.package.controller.CalcController.calcService; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'calcService': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire method: public void my.package.service.impl.MyServiceImpl.setMyService2(my.package.service.MyService2); nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'calcArffService': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private java.lang.String my.package.service.impl.MyService2Impl.PATH_FILES; nested exception is org.springframework.beans.factory.BeanExpressionException: Expression parsing failed; nested exception is org.springframework.expression.spel.SpelEvaluationException: EL1008E:(pos 0): Field or property 'filePath' cannot be found on object of type 'org.springframework.beans.factory.config.BeanExpressionContext'
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:289)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1146)
    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:628)
    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:599)
    at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:665)
    at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:518)
    at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:459)
    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:5176)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5460)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)
    at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
    at java.util.concurrent.FutureTask.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)

我做了一个名为FilePath的POJO：

public class FilePath {

  private String filePath;

  public String getFilePath() {
    return filePath;
  }

  public void setFilePath(String filePath) {
    this.filePath = filePath;
  }

  @Override
  public String toString() {
    return "FilePath [filePath=" + filePath + "]";
  }

}

我将以下内容添加到spring-servlet.xml或application-context.xml：

<context:component-scan base-package="src/main/resources" />
<context:property-placeholder location="classpath*:file-locations.properties" />
<bean id="filePaths"
  class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
  <property name="location" value="classpath:file-locations.properties" />
</bean>
<bean class="ph.edu.upm.agila.gtmeren.bosom.domain.FilePath">
  <property name="filePath" value="${filePath}" />
</bean>

但即使我把这些新代码放在application-context.xml

<context:property-placeholder location="classpath:file-locations.properties" />
<bean class="my.package.FilePath">
    <property name="filePath" value="file-location.properties" />
</bean>

System.out.println(PATH_FILES);的输出为${dir.local}。

Answer 1

放手一步。

定义属性占位符

<context:property-placeholder location="classpath*:file-locations.properties"/>
使用dir.server等
使用$
因此你的bean看起来像是

@Value（“$ {dir.local}”）
private String PATH_FILES;
现在真正的问题是财产是否会被加载。
1. 如果您在部署到服务器后进行测试，请确保该文件位于/WEB-INF/classes/file-locations.properties
2. 如果你正在做一个junit sing eclipse，请确保在project-properties-＆gt;中的文件。 java构建路径 - ＆gt;来源标签。 src/main/resources包含在选项中，包括所有

Answer 2

在继续之前，您需要先查看Spring MVC documentation。如果不是全部，您至少应该阅读上下文层次结构以及哪个ApplicationContext由哪个Web应用程序组件加载。

目前，您的application-context.xml绝对没有用处。正如您所示，您的应用程序中没有任何内容正在使用它。您的DispatcherServlet正在从spring-servlet.xml加载其配置。您需要在那里声明property-placeholder。

字段本身应该是

@Value("${dir.local}")
private String PATH_FILES;

Spring文档也详细解释了SpEL expressions。

Answer 3

以下是我没有任何错误的方法：

我在src/resources。
运行Tomcat后，我会搜索这些文件所在的位置，并且它们位于C:/tomcat/webapp/my_app/WEB-INF/classes/resources。
我创建了一个将C:/tomcat/webapp/my_app/WEB-INF/classes/resources连接到我的文件的函数。

例如，我想写一个文件，我只是这样做：

String filePath = myService.getAbsolutePath() + "file.dat";
BufferedWriter writer = new BufferedWriter(new FileWriter(filePath));

其中.getAbsolutePath()实现只返回MyService类中的文件路径！

注意：一旦上传到服务器，只需重复第二个 - 在放置文件的服务器中进行搜索，并将其替换为.getAbsolutePath()的内容！

你去吧！

用于Tomcat服务器中WAR导出的Spring文件I / O.

3 个答案: