java图片上传剪切图片整套实现方法（1）

1、上传显示图片两个主要方法：public String addLogo(){
  String extName = ""; // 保存文件拓展名  
        String newFileName = ""; // 保存新的文件名  
        String nowTimeStr = ""; // 保存当前时间  
//  //重命名图片名称
//  logoFileName=System.currentTimeMillis()+logoFileName;
//  //获得upload的绝对路径
//  String realPath = ServletActionContext.getServletContext().getRealPath("uploadImages");
//  //获得该图片的绝对路径
//  File file = new File(new File(realPath), logoFileName);
  PrintWriter out = null; 
        SimpleDateFormat sDateFormat; 
        Random r = new Random(); 
        String savePath = ServletActionContext.getServletContext().getRealPath( 
                ""); // 获取项目根路径  
        savePath = savePath.replace("\", "\\\\");
  savePath = savePath + "\\\\uploadImages\\\\";
        HttpServletResponse response = ServletActionContext.getResponse();
        HttpServletRequest request = ServletActionContext.getRequest();
        response.setCharacterEncoding("gbk"); // 务必，防止返回文件名是乱码  
        // 生成随机文件名：当前年月日时分秒+五位随机数（为了在实际项目中防止文件同名而进行的处理）  
        int rannum = (int) (r.nextDouble() * (99999 - 10000 + 1)) + 10000; // 获取随机数  
        sDateFormat = new SimpleDateFormat("yyyyMMddHHmmss"); // 时间格式化的格式  
        nowTimeStr = sDateFormat.format(new Date()); // 当前时间  
        // 获取拓展名  
        if (logoFileName.lastIndexOf(".") >= 0) { 
            extName = logoFileName.substring(logoFileName 
                    .lastIndexOf(".")); 
        } 
        HttpSession session = request.getSession();
  try{
   String powerStr = session.getAttribute("power").toString();
   int power=0;
   if(powerStr==null){
    request.setAttribute("failMsg", "异常操作，用户已退出，请重新登录！");
    return "login";
   }else{
    power = Integer.parseInt(powerStr);
   }
   if(power==2){
    
    out = response.getWriter(); 
    newFileName = nowTimeStr + rannum + extName; // 文件重命名后的名字  
    String filePath = savePath +newFileName; 
    filePath  = filePath .replace("\", "\\\\");
//            String filePathm = savePath +"mdpi_"+ newFileName; 
//            filePathm = filePathm.replace("//", "/");
//            String filePathl = savePath +"ldpi_"+ newFileName; 
//            filePathl = filePathl.replace("//", "/");
//            FileInputStream ins = new FileInputStream(fileupload);
//            System.out.println(ins.available());
//            BufferedImage bi = ImageIO.read(fileupload);;
//            System.out.println(bi.getWidth());
//            System.out.println(bi.getHeight());
    
    //检查上传的是否是图片  
    boolean flagImage=false;
    if (UtilCommon.checkIsImage(extName)) {
     FileInputStream ins = new FileInputStream(logo);
     BufferedImage bi = ImageIO.read(logo);
     if(ins.available()>3*1024*1024){
      out.print("图片大小为"+ins.available()/(1024*1024)+"M"+"，不应超高3M!");
     }else if(bi.getWidth()<150 || bi.getHeight()<100){
      out.print("图片宽度为："+bi.getWidth()+"，图片高度为："+bi.getHeight()+"，宽度不应低于100，高度不应低于100!");
     }else{
      FileUtils.copyFile(logo, new File(filePath));
//               FileUtils.copyFile(logo, new File(filePathm));
//               FileUtils.copyFile(logo, new File(filePathl));
//               zoom(logo, "mdpi_"+newFileName, 150, 100);
//               //zoom(logo, "ldpi_"+newFileName, 100, 60);
      out.print("" + logoFileName 
        + "上传成功!#" + filePath + "#" + logoFileName);
      flagImage=true;
     }
     
    } else { 
     out.print("上传的文件类型错误，请选择jpg格式的图片!"); 
    } 
    
    
    Driver_detail detail = this.dds.getDriver_detailByDriverId(driverId);
    if(flagImage==true){
     if(detail==null){
      String companyIdStr = session.getAttribute("companyId").toString();
      int companyId = Integer.parseInt(companyIdStr);
      Drivers drivers = this.ds.getDriversById(driverId, companyId);
      detail = new Driver_detail();
      detail.setDrivers(drivers);
      detail.setImageUrl(newFileName);
      boolean flag = dds.addDriver_detail(detail);
     }else if(detail.getImageUrl()==null){
      detail.setImageUrl(newFileName);
      dds.updateDriver_detail(detail, detail.getDetailId());
     }else{
      String pimgurl = detail.getImageUrl();
      //要删除的图片绝对路径
      String imgAbl = savePath+File.separator+pimgurl;
//        String imgAblm = savePath+File.separator+"mdpi_"+pimgurl;
//        String imgAbll = savePath+File.separator+"ldpi_"+pimgurl;
      //删除图片
      boolean flagimg = false;
      File file = new File(imgAbl);
//        File filem = new File(imgAblm);
//        File filel = new File(imgAbll);
      if(pimgurl!=null){
       flagimg=file.delete();
//         flagimg=filem.delete();
//         flagimg=filel.delete();
      }
      detail.setImageUrl(newFileName);
      dds.updateDriver_detail(detail, detail.getDetailId());
      
     }
    }
    out.flush(); 
    out.close();
    return null;
   }else{
    request.setAttribute("failMsg", "异常操作，用户已退出，请重新登录！");
    return "login";
   }
   
 
     }catch (CannotCreateTransactionException e) {
   request.setAttribute("failMsg", "数据库连接失败,请联系管理员");
   
  }catch (HibernateException e) {
   request.setAttribute("failMsg", "上传Logo图片失败");
    
  }catch (IOException e) {
   request.setAttribute("failMsg", "上传失败，出错啦!");
  }catch (Exception e) {
   request.setAttribute("failMsg", "上传Logo图片失败");
   
  }
  return null;
 }
 
  public String showImage() throws Exception { 
         // 根据图片地址构造file对象 
    response = ServletActionContext.getResponse();
         File file = new File(imageUrl); 
         InputStream is = new FileInputStream(file); 
         Image image = ImageIO.read(is);// 读图片  
         String imageType = imageUrl.substring(imageUrl.lastIndexOf(".") + 1);
         RenderedImage img = (RenderedImage) image; 
         OutputStream out = response.getOutputStream();
         ImageIO.write(img, imageType, out); 
         out.flush(); 
         out.close(); 
         return null; 
     }