如何在webapp文件夹中上传图像 [英] How to upload image inside webapp folder
本文介绍了如何在webapp文件夹中上传图像的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我正在尝试使用ServletContext将图像文件上传到/webapp/foto/上的文件夹照片，但是每次我遇到NullPointerExceptions
I'm trying to upload image files to folder photos on /webapp/foto/ using ServletContext, but every time I got NullPointerExceptions
我该怎么做?
这是UploadFile.class，其中NPE在CONTAINER_ROOT变量上上升.
Here is the UploadFile.class where NPE is rising on CONTAINER_ROOT variable.
@Component
public class UploadFile {
@Autowired
HttpServletRequest httpServletRequest;
private String CONTAINER_ROOT = httpServletRequest.getSession().getServletContext().getRealPath("/");
private String DIR_NAME = "foto";
private String UPLOAD_DIR = CONTAINER_ROOT + File.separator + DIR_NAME;
private Logger logManager = LogManager.getLogger(this.getClass());
public String getUploadedPath(MultipartFile file) {
return upload(file);
}
private String upload(MultipartFile file) {
if (!file.isEmpty()) try {
byte[] bytes = file.getBytes();
String fileName = file.getOriginalFilename();
File dir = new File(UPLOAD_DIR);
if (!dir.exists()) dir.mkdirs();
File fileOnServer = new File(dir.getAbsolutePath() + File.separator + fileName);
BufferedOutputStream outputStream = new BufferedOutputStream(new FileOutputStream(fileOnServer));
outputStream.write(bytes);
outputStream.close();
logManager.warn("UPLOADED FILE LOCATION: " + fileOnServer.getAbsolutePath());
return fileOnServer.getPath();
}
catch (IOException e) {
logManager.error("Error trying to upload file to location, or file is empty!", e.getMessage());
}
return null;
}
}
这就是我在Controller上使用的方式:
And this is how I use on Controller:
Foto savedFoto = this.fotoRepository.save(new Foto(this.uploadFile.getUploadedPath(file)，savedImovel));
Stacktrace:
The Stacktrace:
Caused by: org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [br.com.agenciadsw.morenoimoveis.util.UploadFile]: Constructor threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:164)
28-Aug-2014 11:02:16.409 WARNING [RMI TCP Connection(2)-127.0.0.1] org.apache.catalina.loader.WebappClassLoader.clearReferencesJdbc The web application [] registered the JDBC driver [com.mysql.jdbc.Driver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:89)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1069)
... 71 more
Caused by: java.lang.NullPointerException
at br.com.agenciadsw.morenoimoveis.util.UploadFile.<init>(UploadFile.java:26)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:408)
at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:148)
... 73 more
这里是 web.xml :
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
version="3.1">
<display-name>MorenoImoveis</display-name>
<servlet>
<servlet-name>dispacher</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextClass</param-name>
<param-value>org.springframework.web.context.support.AnnotationConfigWebApplicationContext</param-value>
</init-param>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>
br.com.agenciadsw.morenoimoveis.cfg.PersistenceConfigurer
br.com.agenciadsw.morenoimoveis.cfg.SecurityConfigurer
br.com.agenciadsw.morenoimoveis.cfg.WebMvcConfigurer
</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>dispacher</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
<context-param>
<param-name>contextClass</param-name>
<param-value>
org.springframework.web.context.support.AnnotationConfigWebApplicationContext
</param-value>
</context-param>
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>
br.com.agenciadsw.morenoimoveis.cfg.PersistenceConfigurer
br.com.agenciadsw.morenoimoveis.cfg.SecurityConfigurer
br.com.agenciadsw.morenoimoveis.cfg.WebMvcConfigurer
</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<filter>
<filter-name>encodingFilter</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter
</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>encodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
</web-app>
推荐答案
您可以将图像上传到项目外部的文件夹中.我有用的几张图片
You could upload image in folder outside the project. I useful for several image
try {
byte[] bytes = file.getBytes();
// Creating the directory to store file
File dir = new File(Utils.getFolderStoreImage(request.getSession().getServletContext().getRealPath("/")));
if (!dir.exists())
dir.mkdirs();
// Create the file on server
serverFile = new File(Utils.getFolderStoreImage(request.getServletContext().getRealPath("/"))+System.currentTimeMillis()+"-"+UUID.randomUUID().toString()+".jpg");
BufferedOutputStream stream = new BufferedOutputStream(new FileOutputStream(serverFile));
stream.write(bytes);
stream.close();
} catch (Exception e) {
result.rejectValue("image", "error when upload image");
return "product/add";
}
Utils.java
Utils.java
public class Utils {
public static String getFolderStoreImage(String webContentRoot) {
if (webContentRoot.endsWith("\\")){
webContentRoot = webContentRoot.substring(0,webContentRoot.length() - 1);
}
String folder = webContentRoot.substring(0, webContentRoot.lastIndexOf("\\") + 1) + "upload\\";
return folder;
}
}
这篇关于如何在webapp文件夹中上传图像的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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