文件上传组件的应用

　注册页面的逻辑处理bean:doReg.java

  其中包括apache上传组件１．２．１的应用

　package huc.blog.servlet;

import huc.blog.bean.User;
import huc.blog.op.UserOp;

import java.io.File;
import java.io.IOException;
import java.util.Date;
import java.text.SimpleDateFormat;
import java.util.List;

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

public class DoReg extends HttpServlet ...{

    /** *//**
     * 
     */
    private static final long serialVersionUID = 1L;

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException ...{
        doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException ...{
        SimpleDateFormat f=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        User user=new User();
        //设置保存上传文件的目录
        String uploadDir=getServletContext().getRealPath("/upload");
        if(uploadDir==null)...{
            System.out.println("该目录无法访问!");
            return;
        }
        
        File fileUploadDir=new File(uploadDir);
        
        if(!fileUploadDir.exists())...{
            if(!fileUploadDir.mkdir())...{
                System.out.println("无法创建目录!");
                return;
            }
        }
        
         //RequestContext requestContext = new ServletRequestContext(req);
        //判断表单中是否为multipart/form-data类型的数据,非则终止
        if(!ServletFileUpload.isMultipartContent(req))...{
            System.out.println("不能处理非multipart/form-data类型的数据!");
            return;
        }
        
        //创建DiskFileItemFactory对象,并进行一些设置
        DiskFileItemFactory factory = new DiskFileItemFactory();
        //设置直接能够存储的最大文件量,超出后采用临时文件缓存
        factory.setSizeThreshold(1024*1024);//以字节为单位
        /**//*Sets the directory used to temporarily store files that 
         *    are larger than the configured size threshold.
         *    默认为tomcat的安装目录 emp下
         */
        //factory.setRepository(java.io.File repository);
        
        ServletFileUpload upload = new ServletFileUpload(factory);
        //设置最多上传的数据量
        upload.setSizeMax(1024*1024*10);
        /** *//**
         * Specifies the character encoding to be used 
         * when reading the headers of individual part. 
         * When not specified, or null, the request encoding is used. 
         * If that is also not specified, or null, the platform default encoding is used. 
         */
        //upload.setHeaderEncoding("UTF-8");
        
        List<?> items=null;
        //得到表单字段的集合
        try...{
            
             items = upload.parseRequest(req);
             
        }catch(FileUploadException e)...{
            e.printStackTrace();
        }
        for(Object item:items)...{
            
            FileItem fileItem=(FileItem)item;
            //Determines whether or not a FileItem instance represents a simple form field. 
            if(fileItem.isFormField())...{
                
                // Returns the contents of the file item as a String, using the specified encoding.
                String content=fileItem.getString("UTF-8");
                String fieldName=fileItem.getFieldName();
                
                if(fieldName.equals("userName"))...{
                    user.setUserName(content);
                }else if(fieldName.equals("nickName"))...{
                    user.setNickName(content);
                }else if(fieldName.equals("userPass"))...{
                    user.setUserPass(content);
                }else if(fieldName.equals("email"))...{
                    user.setEmail(content);
                }else if(fieldName.equals("city"))...{
                    user.setCity(content);
                }else if(fieldName.equals("spaceName"))...{
                    user.setSpaceName(content);
                }    
            }else...{
                //Returns the original filename in the client's filesystem, 
                //as provided by the browser (or other client software).
                String source=fileItem.getName();
                
                //如果没有选择文件,则不进行处理
                if(source.trim().equals(""))...{
                    continue;
                }
                
                //得到上传的文件名
                int pos=source.lastIndexOf("/");
                String fileName=source.substring(pos+1);
                File file=new File(uploadDir,fileName);
                
                //write an uploaded item to disk
                try ...{
                    fileItem.write(file);
                } catch (Exception e) ...{
                    e.printStackTrace();
                }finally...{
                    //Deletes the underlying(潜在的)storage for a file item, 
                    //including deleting any associated temporary disk file
                    fileItem.delete();
                }
            }
        }
        Date date=new Date();
        user.setRegDate(f.format(date));
        user.setUpdateTime(f.format(date));
        
        UserOp userOp=new UserOp();
        
        if(!userOp.checkNotExist(user))...{
            String msg="该用户已存在,请重新填写!";
            req.setAttribute("msg",msg);
            req.getRequestDispatcher("../reg.jsp").forward(req,resp);
            return;
        }
        if(userOp.add(user))...{
            req.setAttribute("info", "success");
            req.getRequestDispatcher("../reginfo.jsp").forward(req, resp);
        }else...{
            req.setAttribute("info","failed");
            req.getRequestDispatcher("../reginfo.jsp").forward(req, resp);
        }
    }
    
}