Java 如何在 spring mvc 控制器中获取 getServletContext()

how to get getServletContext() in spring mvc Controller

提问by Priyanka Shaju

I need to upload images in my project. How to get the upload path in SpringMVC. The path is;

我需要在我的项目中上传图片。SpringMVC中如何获取上传路径。路径是;

/home/cme/project/eclipse/workspace_12_11/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/fileUploadTester/upload

The following error;

以下错误；

The method getServletContext() is undefined for the type HomePageController

appears when I use this code;

当我使用此代码时出现；

String uploadPath = getServletContext().getRealPath("") + File.separator + UPLOAD_DIRECTORY;

My code is

我的代码是

public ModelAndView UploadPhoto(@ModelAttribute User user, HttpServletRequest request, HttpServletResponse response) throws IOException {
 final String UPLOAD_DIRECTORY = "upload";
 final int THRESHOLD_SIZE = 1024 * 1024 * 3; // 3MB
 final int MAX_FILE_SIZE = 1024 * 1024 * 40; // 40MB
 final int MAX_REQUEST_SIZE = 1024 * 1024 * 50; // 50MB

 String value[] = new String[10];
 int i = 0;

 // checks if the request actually contains upload file
 if (!ServletFileUpload.isMultipartContent(request)) {
  PrintWriter writer = response.getWriter();
  writer.println("Request does not contain upload data");
  writer.flush();
  return; //here is error This method must return a result of type ModelAndView
 }

 DiskFileItemFactory factory = new DiskFileItemFactory();
 factory.setSizeThreshold(THRESHOLD_SIZE);
 factory.setRepository(new File(System.getProperty("java.io.tmpdir")));

 ServletFileUpload upload = new ServletFileUpload(factory);
 upload.setFileSizeMax(MAX_FILE_SIZE); //here error The method setFileSizeMax(int) is undefined for the type ServletFileUpload
 upload.setSizeMax(MAX_REQUEST_SIZE);
 String uploadPath = getServletContext().getRealPath("") + File.separator + UPLOAD_DIRECTORY; // here error The method getServletContext() is undefined for the type Homepage Controller
 // creates the directory if it does not exist
 File uploadDir = new File(uploadPath);
 if (!uploadDir.exists()) {
  uploadDir.mkdir();
 }

 try {
  List < FileItem > items = upload.parseRequest(request); // request is HttpServletRequest
  for (FileItem item: items) {
   if (item.isFormField()) { // text fields, etc...
    String fieldName = item.getFieldName();
    System.out.print("fieldname" + fieldName);
    value[i] = item.getString();
    System.out.print("from uploader" + value[i]);
    i++;
   } else {
    //String fileName=new File(item.getName()).getName();   Use this to use default file name
    String name = value[0];
    System.out.println("file uploader name" + name);
    String filePath = uploadPath + File.separator + name;
    System.out.println(filePath);
    File storeFile = new File(filePath);
    try {
     item.write(storeFile);
    } catch (Exception ex) {
    }
   }
  }
  System.out.println("uploaded successfully");
 } catch (Exception ex) {
  System.out.println("error not uploaded");
 }
 return new ModelAndView("ChangePhoto");
}

Three error

三误

1. This method must return a result of type ModelAndView
2. The method setFileSizeMax(int) is undefined for the type ServletFileUpload
3. The method getServletContext() is undefined for the type Homepage Controller

1. 此方法必须返回 ModelAndView 类型的结果
2. ServletFileUpload 类型的 setFileSizeMax(int) 方法未定义
3. 对于主页控制器类型，方法 getServletContext() 未定义

采纳答案by Nirav Prajapati

1. Use below code to autowire ServletContextobject in SpringMVC

   @Autowired
   ServletContext context; 
   

   and after that try to execute your code like

   String uploadPath = context.getRealPath("") + File.separator + UPLOAD_DIRECTORY;
   

2. You can get it in your controller like this;

   private ServletContext context;
   
   public void setServletContext(ServletContext servletContext) {
       this.context = servletContext;
   }
   

   but for this your controller must implement ServletContextAwareinterface

1. 使用以下代码ServletContext在 SpringMVC 中自动装配对象

   @Autowired
   ServletContext context; 
   

   然后尝试执行您的代码，例如

   String uploadPath = context.getRealPath("") + File.separator + UPLOAD_DIRECTORY;
   

2. 你可以像这样在你的控制器中得到它；

   private ServletContext context;
   
   public void setServletContext(ServletContext servletContext) {
       this.context = servletContext;
   }
   

   但为此您的控制器必须实现ServletContextAware接口

回答by Priyanka Shaju

Try this:

尝试这个：

@Autowired
ServletContext servletContext;

回答by user3502676

This is just another alternative

这只是另一种选择

((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest().getServletContext()

回答by Arun Raaj

The parameters you passed or set to the ServletContext object, are stored into HttpServletRequest object, you can access them anywhere in application in following way:

您传递或设置给 ServletContext 对象的参数存储在 HttpServletRequest 对象中，您可以通过以下方式在应用程序的任何位置访问它们：

public void method(HttpServletRequest request){
    String email=request.getServletContext().getInitParameter(“email”);
}