<div class="panel panel-warning addDiv">
	  <div class="panel-heading">新增分类</div>
	  <div class="panel-body">
	    	<form method="post" id="addForm" action="admin_category_add" enctype="multipart/form-data">
	    		<table class="addTable">
	    			<tr>
	    				<td>分类名称</td>
	    				<td><input  id="name" name="name" type="text" class="form-control"></td>
	    			</tr>
	    			<tr>
	    				<td>分类圖片</td>
	    				<td>
	    					<input id="categoryPic" accept="image/*" type="file" name="filepath" />
	    				</td>
	    			</tr>
	    			<tr class="submitTR">
	    				<td colspan="2" align="center">
	    					<button type="submit" class="btn btn-success">提 交</button>
	    				</td>
	    			</tr>
	    		</table>
	    	</form>
	  </div>
	</div>

<script>
$(function(){
	
	$("#addForm").submit(function(){
		if(!checkEmpty("name","分类名称"))
			return false;
		if(!checkEmpty("categoryPic","分类图片"))
			return false;
		return true;
	});
});

</script>

	public String add(HttpServletRequest request, HttpServletResponse response, Page page) {
		Map<String,String> params = new HashMap<>();
		InputStream is = super.parseUpload(request, params);
		
		String name= params.get("name");
		Category c = new Category();
		c.setName(name);
		categoryDAO.add(c);
		
		File  imageFolder= new File(request.getSession().getServletContext().getRealPath("img/category"));
		File file = new File(imageFolder,c.getId()+".jpg");
		
		try {
			if(null!=is && 0!=is.available()){
			    try(FileOutputStream fos = new FileOutputStream(file)){
			        byte b[] = new byte[1024 * 1024];
			        int length = 0;
			        while (-1 != (length = is.read(b))) {
			            fos.write(b, 0, length);
			        }
			        fos.flush();
			        //通过如下代码，把文件保存为jpg格式
			        BufferedImage img = ImageUtil.change2jpg(file);
			        ImageIO.write(img, "jpg", file);		
			    }
			    catch(Exception e){
			    	e.printStackTrace();
			    }
			}
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}	
		return "@admin_category_list";
	}

package tmall.util;

import java.awt.Image;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.DataBuffer;
import java.awt.image.DataBufferInt;
import java.awt.image.DirectColorModel;
import java.awt.image.PixelGrabber;
import java.awt.image.Raster;
import java.awt.image.RenderedImage;
import java.awt.image.WritableRaster;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

public class ImageUtil {

	public static BufferedImage change2jpg(File f) {
		try {
			java.awt.Image i = Toolkit.getDefaultToolkit().createImage(f.getAbsolutePath());
			PixelGrabber pg = new PixelGrabber(i, 0, 0, -1, -1, true);
			pg.grabPixels();
			int width = pg.getWidth(), height = pg.getHeight();
			final int[] RGB_MASKS = { 0xFF0000, 0xFF00, 0xFF };
			final ColorModel RGB_OPAQUE = new DirectColorModel(32, RGB_MASKS[0], RGB_MASKS[1], RGB_MASKS[2]);
			DataBuffer buffer = new DataBufferInt((int[]) pg.getPixels(), pg.getWidth() * pg.getHeight());
			WritableRaster raster = Raster.createPackedRaster(buffer, width, height, width, RGB_MASKS, null);
			BufferedImage img = new BufferedImage(RGB_OPAQUE, raster, false, null);
			return img;
		} catch (InterruptedException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			return null;
		}
	}

	public static void resizeImage(File srcFile, int width,int height, File destFile) {
		try {
			Image i = ImageIO.read(srcFile);
			i = resizeImage(i, width, height);
			ImageIO.write((RenderedImage) i, "jpg", destFile);
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	
	public static Image resizeImage(Image srcImage, int width, int height) {
		try {

			BufferedImage buffImg = null;
			buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
			buffImg.getGraphics().drawImage(srcImage.getScaledInstance(width, height, Image.SCALE_SMOOTH), 0, 0, null);

			return buffImg;
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return null;
	}

}

package tmall.filter;
 
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
 
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
public class EncodingFilter implements Filter {
 
    @Override
    public void destroy() {
 
    }
 
    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
            throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) req;
        HttpServletResponse response = (HttpServletResponse) res;
 
        request.setCharacterEncoding("UTF-8");
 
        chain.doFilter(request, response);
    }
 
    @Override
    public void init(FilterConfig arg0) throws ServletException {
 
    }
 
}

package tmall.servlet;

import java.io.InputStream;

import java.lang.reflect.Method;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

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

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

import tmall.dao.CategoryDAO;
import tmall.dao.OrderDAO;
import tmall.dao.OrderItemDAO;
import tmall.dao.ProductDAO;
import tmall.dao.ProductImageDAO;
import tmall.dao.PropertyDAO;
import tmall.dao.PropertyValueDAO;
import tmall.dao.ReviewDAO;
import tmall.dao.UserDAO;
import tmall.util.Page;

public abstract class BaseBackServlet extends HttpServlet {

	public abstract String add(HttpServletRequest request, HttpServletResponse response, Page page) ;
	public abstract String delete(HttpServletRequest request, HttpServletResponse response, Page page) ;
	public abstract String edit(HttpServletRequest request, HttpServletResponse response, Page page) ;
	public abstract String update(HttpServletRequest request, HttpServletResponse response, Page page) ;
	public abstract String list(HttpServletRequest request, HttpServletResponse response, Page page) ;
	
	protected CategoryDAO categoryDAO = new CategoryDAO();
	protected OrderDAO orderDAO = new OrderDAO();
	protected OrderItemDAO orderItemDAO = new OrderItemDAO();
	protected ProductDAO productDAO = new ProductDAO();
	protected ProductImageDAO productImageDAO = new ProductImageDAO();
	protected PropertyDAO propertyDAO = new PropertyDAO();
	protected PropertyValueDAO propertyValueDAO = new PropertyValueDAO();
	protected ReviewDAO reviewDAO = new ReviewDAO();
	protected UserDAO userDAO = new UserDAO();

	public void service(HttpServletRequest request, HttpServletResponse response) {
		try {
			
			/*获取分页信息*/
			int start= 0;
			int count = 5;
			try {
				start = Integer.parseInt(request.getParameter("page.start"));
			} catch (Exception e) {
				
			}
			try {
				count = Integer.parseInt(request.getParameter("page.count"));
			} catch (Exception e) {
			}
			Page page = new Page(start,count);
			
			/*借助反射，调用对应的方法*/
			String method = (String) request.getAttribute("method");
			Method m = this.getClass().getMethod(method, javax.servlet.http.HttpServletRequest.class,
					javax.servlet.http.HttpServletResponse.class,Page.class);
			String redirect = m.invoke(this,request, response,page).toString();
			
			/*根据方法的返回值，进行相应的客户端跳转，服务端跳转，或者仅仅是输出字符串*/
			if(redirect.startsWith("@"))
				response.sendRedirect(redirect.substring(1));
			else if(redirect.startsWith("%"))
				response.getWriter().print(redirect.substring(1));
			else
				request.getRequestDispatcher(redirect).forward(request, response);
			
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			throw new RuntimeException(e);
		}
	}
	public InputStream parseUpload(HttpServletRequest request, Map<String, String> params) {
			InputStream is =null;
			try {
	            DiskFileItemFactory factory = new DiskFileItemFactory();
	            ServletFileUpload upload = new ServletFileUpload(factory);
	            // 设置上传文件的大小限制为10M
	            factory.setSizeThreshold(1024 * 10240);
	             
	            List items = upload.parseRequest(request);
	            Iterator iter = items.iterator();
	            while (iter.hasNext()) {
	                FileItem item = (FileItem) iter.next();
	                if (!item.isFormField()) {
	                    // item.getInputStream() 获取上传文件的输入流
	                    is = item.getInputStream();
	                } else {
	                	String paramName = item.getFieldName();
	                	String paramValue = item.getString();
	                	paramValue = new String(paramValue.getBytes("ISO-8859-1"), "UTF-8");
	                	params.put(paramName, paramValue);
	                }
	            }
	             
	        } catch (Exception e) {
	            e.printStackTrace();
	        }
			return is;
		}
	
}