Java Servlet图片上传至指定文件夹并显示图片

    

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   commons-io
   commons-io
   2.4


   commons-fileupload
   commons-fileupload
   1.3.1

package servlet;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Iterator;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

public class UploadPhotoServlet extends HttpServlet {
    public static String filename = null;
    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    public void doGet(HttpServletRequest request,HttpServletResponse response){
        
    }

    @SuppressWarnings("rawtypes")
    public void doPost(HttpServletRequest request,HttpServletResponse response) throws IOException, ServletException{
        DiskFileItemFactory factory = new DiskFileItemFactory();
        ServletFileUpload upload = new ServletFileUpload(factory);
        
        factory.setSizeThreshold(1024 * 1024);
        List items = null;
        try {
            items = upload.parseRequest(request);
        } catch (FileUploadException e) {
            e.printStackTrace();
        }
        
        Iterator iter = items.iterator();
        while(iter.hasNext()){
            FileItem item = (FileItem) iter.next();
            if(!item.isFormField()){
                
                // 根据时间戳创建头像文件
                filename = System.currentTimeMillis() + ".jpg";
                System.out.println(request.getContextPath());
                /*File f = new File(getServletContext().getRealPath("upload"));*/
                File f = new File("D://image");
                if (!f.exists()) {  
                    f.mkdir();  
                } 
                String imgsrc = f + "/" + filename;
                
                // 复制文件
                InputStream is = item.getInputStream();               
                FileOutputStream fos = new FileOutputStream(imgsrc);
                byte b[] = new byte[1024 * 1024];
                int length = 0;
                while (-1 != (length = is.read(b))) {
                    fos.write(b, 0, length);                    
                }
                fos.flush();
                fos.close();  
                
            }else {
                System.out.println(item.getFieldName());
                String value = item.getString();
                value = new String(value.getBytes("ISO-8859-1"), "UTF-8");
                System.out.println(value);
            }
        }         
        //request.setAttribute("filename", filename);      
        //request.getRequestDispatcher("/showPhoto").forward(request, response);
        response.sendRedirect("/ServletTest/showPhoto?filename="+filename);      
    }
}

package servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ShowPhotoServlet extends HttpServlet{
    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    public void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException{
        String filename = request.getParameter("filename").toString();
        response.sendRedirect("/ServletTest/showphoto.jsp?filename="+filename);    
    }
    
    public void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException{
        String filename = request.getAttribute("filename").toString();
        request.setAttribute("filename", filename);
        request.getRequestDispatcher("/showphoto.jsp").forward(request, response);
    }
}

　　 request.setAttribute("filename", filename);

　　 request.getRequestDispatcher("/showphoto.jsp").forward(request, response);　

　　 response.sendRedirect("/ServletTest/showphoto.jsp?filename="+filename);    

　　 String filename = request.getAttribute("filename").toString();

　　 String filename = request.getParameter("filename").toString();

    
        UploadPhotoServlet
        servlet.UploadPhotoServlet
     
    
        UploadPhotoServlet
        /uploadPhoto
      
    
    
        ShowPhotoServlet
        servlet.ShowPhotoServlet
     
    
        ShowPhotoServlet
        /showPhoto
     

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