jsp 如何从数据库中读取二进制文件（图片）并显示

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#热议# 生活中有哪些实用的心理学知识？

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2006-05-09 · TA获得超过445个赞

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提供的jsp页面代码：
<%@ page contentType="text/html;charset=gb2312"%>
<%@ taglib uri="struts/html" prefix="html" %>
<%@ taglib uri="struts/bean" prefix="bean" %>
<%@ taglib uri="struts/logic" prefix="logic" %>
<link rel="stylesheet" href="/dbsd/public.css" type="text/css">
<html:html>
<head><title>上传照片</title></head>
<body>
<%
    String type=String.valueOf(request.getParameter("type"));
    int i;
   if("old".equals(type)){
            i=0;
    }else{
    i=1;
}
%>
<script language="javascript">
        function addInfo(){
           if(document.PhotosForm.explain.value==""){
                    alert("请填写说明内容！");
                      return false;
              }
           if(document.PhotosForm.schoolPhoto.value==""){
                       alert("请选择照片文件！");
                      return false;
              }

             if((document.PhotosForm.schoolPhoto.value.indexOf(".jpg"))>0||(document.PhotosForm.schoolPhoto.value.indexOf(".bmp")>0)||(document.PhotosForm.schoolPhoto.value.indexOf(".gif")>0)||(document.PhotosForm.schoolPhoto.value.indexOf(".JPG"))>0||(document.PhotosForm.schoolPhoto.value.indexOf(".BMP")>0)||(document.PhotosForm.schoolPhoto.value.indexOf(".GIF")>0)){
                          return true;
            }else{
             alert("请选择照片格式（.bmp或.jpg或.gif文件）！");
            return false;
            }
           }
</script>

<html:form action="uploadSchoolPhoto.do" method="post" enctype="multipart/form-data">

 <table align="center" width=778 align=center bgcolor="#f0faff" cellspacing=0 border=0>
      <tr>
         <td align="center"  ><font size="5" >上传照片</font></td>
      </tr>
      <tr>
           <td>
  <table align="center">
     <tr>
          <td>
               <a href=/dbsd/schoolPhoto/schoolPhoto.jsp>  师大首页</a>-->

            <%
             if("old".equals(type)) out.print("<a href=\"/dbsd/queryOldPhoto.do\">校园老照片</a>-->上传老照片");
             else out.print("<a href=\"/dbsd/queryNewPhoto.do\">校园新貌</a>-->上传新照片");
           %>

           </td>
     </tr>

     <tr>
          <td><div align="right">照    片：</div></td>
          <td><html:file property="schoolPhoto" size="50"/></td>
     </tr>
       <tr>
       <td><html:errors property="schoolPhotoa"/></td><td><html:errors property="schoolPhotob"/></td>     </tr>
     <tr>

          <td><input type="hidden" name="state" value="<%=i%>"/></td>

     </tr>
     <tr>
          <td><div align="right">注释内容：</div></td>
          <td><html:text property="explain" size="50"/></td>
     </tr>
      <tr>
       <td></td>
        <td ><html:errors property="explain"/></td>
     </tr>
      <td colspan="2">
              <div align="center">
                <html:submit onclick="return(addInfo())">上传</html:submit>
                <html:reset>重填</html:reset>
              </div></td>
          </tr>
  </table>
      </td>
            </tr>
                  </table>
</html:form>
</body>
</html:html>

主要的java类：
package com.toowell.schoolPhoto.action;

import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.Action;
import org.apache.struts.upload.FormFile;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.sql.ResultSet;
import java.util.Vector;
import java.io.*;

import com.toowell.common.DbBean;
import com.toowell.common.Util;
import com.toowell.common.Upload;
import com.toowell.common.UserUtil;
import com.toowell.common.page.PageBean;
import com.toowell.schoolPhoto.form.PhotosForm;
import com.toowell.schoolPhoto.model.PhotosBean;
import com.toowell.schoolPhoto.model.PhotosVo;

/**
 * Created by IntelliJ IDEA.
 * User: Administrator
 * Date: 2005-10-27
 * Time: 9:11:05
 * To change this template use Options | File Templates.
 */
public class PhotoShowAction extends Action {
    public ActionForward execute(ActionMapping mapping,
                                 ActionForm    form,
                                 HttpServletRequest request,
                                 HttpServletResponse response) throws Exception{

        String parameter= mapping.getParameter();

boolean isAdmin=UserUtil.isAdmin(request);
        boolean isAudit=UserUtil.isAudit(request);
        //查询老照片
        if("old".equalsIgnoreCase(parameter)) {
            String sql="select * from schoolPhoto where state=0 and audit=1 order by id desc";
            if(isAdmin){
             sql=null;
             sql="select * from schoolPhoto where state=0 order by id desc";
            }
            System.out.println(sql);
            PageBean pageBean =new PageBean();
            pageBean.pageshow(request,sql,"com.toowell.schoolPhoto.model.PhotosList",16);

            request.setAttribute("type","old");
            return mapping.findForward("success");
        }
          //查询新照片
        if("new".equalsIgnoreCase(parameter)) {
            String sql="select * from schoolPhoto where state=1 and audit=1 order by id desc";
            if(isAdmin){
             sql=null;
             sql="select * from schoolPhoto where state=1 order by id desc";
            }
            System.out.println(sql);
            PageBean pageBean =new PageBean();
            pageBean.pageshow(request,sql,"com.toowell.schoolPhoto.model.PhotosList",16);
            request.setAttribute("type","new");
            return mapping.findForward("success");
        }
         //
        if("add".equalsIgnoreCase(parameter)) {
             String servletDir = servlet.getServletContext().getRealPath("/schoolPhoto/images");
             PhotosForm photos=(PhotosForm)form;
             String explain=Util.changeCode(photos.getExplain());

            String state=photos.getState();
            int type=Integer.parseInt(state);
            int id=0;
             try{
            id = PhotosBean.getNowID()+1;
           } catch(Exception e){
            return mapping.findForward("imageError");
           }
              //获取上传的图片文件
        FormFile formFile = photos.getSchoolPhoto();
        //上传位置加上文件名，不含扩展名。回为扩展名可以自动判断
        String dir = servletDir + "/" +id;

        Upload up = new Upload(formFile,dir);
         up.upload();
            String imageType =up.getFileType();
            PhotosVo photosVo=new PhotosVo();
            photosVo.setId(id);
            photosVo.setImageType(imageType);
            photosVo.setExplain(explain);
        try{
           PhotosBean.add(photosVo,state);
        }catch(Exception e){
            return mapping.findForward("imageError");
        }
                  if(type==0){

                      request.setAttribute("type","old");
                      return mapping.findForward("oldSuccess");
               } else{
                        request.setAttribute("type","new");
                      return mapping.findForward("newSuccess");
               }
        }

        if("delete".equalsIgnoreCase(parameter)) {
             String servletDir = servlet.getServletContext().getRealPath("/schoolPhoto/images");
             String id=request.getParameter("id");
             ResultSet rs=null;
            int state=0;
            //删除照片
            String sqlImageType="select imageType,state from schoolPhoto where id="+id;
               try{
               rs= DbBean.getRs(sqlImageType);
               rs.next();
               String imageType=rs.getString(1);
              state=rs.getInt(2);
               String imageName = id+imageType;

             File file = new File(servletDir,imageName);
               file.delete();
               DbBean.close();
            }catch(Exception e){
               return mapping.findForward("imageError");
            }
            //删除照片数据库记录
            String sql="delete from schoolPhoto where id="+id;
            try{
                DbBean.execute(sql);
                DbBean.close();
            }catch(Exception e){
                return mapping.findForward("imageError");
            }
               if(state==0){

                      request.setAttribute("type","old");
                      return mapping.findForward("oldSuccess");
               } else{
                        request.setAttribute("type","new");
                      return mapping.findForward("newSuccess");
               }

}

         if("modify".equalsIgnoreCase(parameter)) {
             ResultSet rs=null;
             Vector list=new Vector();
             String id=request.getParameter("id");
            String sql="select * from schoolPhoto where id="+id;
             String servletDir = servlet.getServletContext().getRealPath("/schoolPhoto/images");
              String state=request.getParameter("type");
            try{
                rs=DbBean.getRs(sql);

                while(rs.next()){
                    PhotosVo photosVo=new PhotosVo();
                    photosVo.setId(rs.getInt(1));
                    photosVo.setImageType(rs.getString(2));
                    photosVo.setExplain(rs.getString(3));
                    photosVo.setState(rs.getInt(6));
                    list.add(photosVo);
                }
            }catch(Exception e){
                return mapping.findForward("imageError");
            }

             request.setAttribute("listPhoto",list);
               if(state.equals("old")){

                      request.setAttribute("type","old");

               } else{
                        request.setAttribute("type","new");

               }
            return mapping.findForward("success");
        }
         if("modifyOne".equalsIgnoreCase(parameter)) {
             String id=request.getParameter("id");

             PhotosForm photo=(PhotosForm)form;
             String explain=Util.changeCode(photo.getExplain());
            int state=Integer.parseInt(photo.getState());
             System.out.println("----=-=-=-=-=--"+state);
            String sql="update schoolPhoto set explain='"+explain+"',audit=0 where id="+id;
             System.out.println(sql);
            try{
                DbBean.execute(sql);
                DbBean.close();
            }catch(Exception e){
                 return mapping.findForward("imageError");
            }
          if(state==0){

                      request.setAttribute("type","old");
                      return mapping.findForward("oldSuccess");
               } else{
                        request.setAttribute("type","new");
                      return mapping.findForward("newSuccess");
               }
        }
         if("audit".equalsIgnoreCase(parameter)) {
             String id=request.getParameter("id");
            String state=request.getParameter("type");
            String sql="update schoolPhoto set audit=1 where id="+id;
            // System.out.println(sql);
            try{
                DbBean.execute(sql);
                DbBean.close();
            }catch(Exception e){
                return mapping.findForward("imageError");
            }
            if(state.equals("old")){

                      request.setAttribute("type","old");
                      return mapping.findForward("oldSuccess");
               } else{
                        request.setAttribute("type","new");
                      return mapping.findForward("newSuccess");
               }
        }
        return null;
    }
}

以上代码仅供参考，恕不能提供更多的代码；
祝好运


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jsp 如何从数据库中读取二进制文件（图片）并显示

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