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我正在研究Java應用程序，我想要做的是向用戶提供上傳圖像並在其個人資料中查看的功能。我知道類似的問題已經回答了很多次，但這是我第一次這樣做，而且我真的很努力使它工作。Jsp從webapps加載圖像ROOT文件夾
所以這是我的測試代碼：
upload.jsp
...
<body>
<form method="post" action="FileUploader" encType="multipart/form-data">
<input type="file" name="file" value="select images..."/>
<input type="submit" value="start upload"/>
</form>
</body>
...
FileUploader.java
正如你所看到的，我在我的所有圖像保存在Tomcat的webapps/ROOT/files夾。
@WebServlet("/FileUploader")
public class FileUploader extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
PrintWriter out = response.getWriter();
if(!ServletFileUpload.isMultipartContent(request)){
out.println("Nothing to upload");
return;
}
FileItemFactory itemfactory = new DiskFileItemFactory();
ServletFileUpload upload = new ServletFileUpload(itemfactory);
try{
List<FileItem> items = upload.parseRequest(new ServletRequestContext(request));
for(FileItem item:items){
String contentType = item.getContentType();
if(!contentType.equals("image/png")){
out.println("only png format image files supported");
continue;
}
File uploadDir = new File("/home/agg/apache-tomcat/webapps/ROOT/files");
File file = File.createTempFile("img",".png",uploadDir);
item.write(file);
out.println("Filename: " + file.getName());
out.println("File Saved Successfully");
response.sendRedirect("message.jsp");
}
}
catch(FileUploadException e){
out.println("upload fail");
}
catch(Exception ex){
out.println("can't save");
}
}
}
message.jsp
在這裏，我試圖加載通過另一個servlet保存的圖像之一。
...
<body>
<img src="file/img1.png">
</body>
FileServlet.java
的Servlet檢索圖像。
@WebServlet("/file/*")
public class FileServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private static final int DEFAULT_BUFFER_SIZE = 10240; // 10KB.
private String filePath;
public void init() throws ServletException {
this.filePath = "/files";
}
protected final void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("================In do get==================");
// Get requested file by path info.
String requestedFile = request.getPathInfo();
System.out.println("Requested File: " + requestedFile);
// Check if file is actually supplied to the request URI.
if (requestedFile == null) {
response.sendError(HttpServletResponse.SC_NOT_FOUND); // 404.
return;
}
// Decode the file name (might contain spaces and on) and prepare file object.
File file = new File(filePath, URLDecoder.decode(requestedFile, "UTF-8"));
System.out.println("Filename: " + file.getName());
System.out.println(file.getAbsolutePath());
// Check if file actually exists in filesystem.
if (!file.exists()) {
System.out.println("DOES NOT EXIST");
response.sendError(HttpServletResponse.SC_NOT_FOUND); // 404.
return;
}
// more code here but it does not matter
}
}
問題是圖像無法加載。在控制檯上打印的路徑似乎是正確的。我在這裏錯過了什麼？