文件上传与下载————>struts

川长思鸟来 2022-06-13 14:21 237阅读 0赞

下载时设置前台的响应类型：response.setContentType("application/x-download");  
os = response.getOutputStream();  
is = new FileInputStream(new File(path));  
  
上传时设置前台的相应类型：response.setContentType("text/html;charset=gb2312");  
FileOutputStream fos = new FileOutputStream(tempFile + filePath + "\\\\" + fileName);  
fos.write(fileItem.get());

乱码转换：

EncodeFilter类实现servlet包下的Filter接口  
doFilter方法中：  
request.setCharacterEncoding("UTF-8");    //将请求以UTF-8形式传输  
chain.doFilter(request, response);    //将请求放行

action中：  
UpLoadForm upLoadForm = (UpLoadForm)form;  
FormFile photo = upLoadForm.getPhoto();    //FormFile是formBean中定义的文件类型

oracle函数:

nvl(a,b)：       如果a不为空则返回a，否则返回b

nvl(a,b,c)：    如果a不为空则返回b，否则返回c

decode(value,if1,then1,if2,then2,if3,then3,…,else)表示value等于if1时, 结果是then1。。。

select instr(“yuechaotianyuechao”,”ao”,-1,1)position from dual;(-1是开始位置,1是次数) — 17

substr(“abcde”,-6,5 )=null    -6是从右往左数第6个位置开始，5是要取得字符串长度

substr(“abcde”,-5,5 )= abcde       -6是从右往左数第6个位置开始，5是要取得字符串长度

mod(a,b)：  对a和b取余

row\_number() over(partition by … order by …)

UpLoadForm upLoadForm = (UpLoadForm)form;  
FormFile photo = upLoadForm.getPhoto();  
response.setContentType("text/html;charset=UTF-8");    //设置输出内容格式  
String fileName = photo.getFileName();          
InputStream contentStream = photo.getInputStream();  
String saveDir = this.getServlet().getServletContext().getRealPath("/");  
File filePhoto = new File(saveDir,fileName);  
FileOutputStream fos = new FileOutputStream(filePhoto );  
/\*\*  
int len =0;  
byte\[\] buf = new byte\[1024\];    //创建1024字节的byte数组  
while((len = contentStream.read(buf)) != -1)    //如果读到内容  
\{  
     fos.write(buf,0,len);    //将读到的下标从0到len长度的内容输出到文件输出流中  
 \}      
\*/  
fos.write(upLoadForm.getPhoto().getFileData());//代替上面几行  
contentStream .close();    //关闭流

fos.close();    //关闭流

第一步：编写页面文件

<%@ page language="**java**" pageEncoding="UTF-8"%>  
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">  
<html>  
  <head>  
    <[%@include][include]file="/header.jsp"%>  
    <title>**struts**上传文件</title>  
  </head>  
  <body>  
   <h2>使用**Struts**上传文件</h2>  
     <hr/>  
    <form. action="<%=basePath%>**strutsfileupload.do?method=upload**" method="**post**"  
           enctype="**multipart/form-data**">  
       <table>  
         <tr>  
           <td>请选择要上传的文件</td>  
           <td>  
              <input type="**file**" name="filePath" size="20"/><br/>  
           </td>  
         </tr>  
         <tr>  
            <td>  
              <input type="submit" value="上传"/>  
            </td>  
            <td>  
              <a href="<%=basePath%>strutsfileupload.do?method=download&path=fileload/xxxx.txt">我要下载</a>  
            </td>  
         </tr>  
        </table>  
    </form>  
  </body>  
</html>  
第二步：**struts**\-config.xml文件，包含form-bean 和action的配置

<?xml version="1.0" encoding="UTF-8"?>  
<!DOCTYPE **struts**\-config PUBLIC "-//Apache Software Foundation//DTD **Struts** Configuration 1.2//EN" "[http://**struts**.apache.org/dtds/**struts**\-config\_1\_2.dtd][http_struts_.apache.org_dtds_struts_-config_1_2.dtd]">  
 <data-sources />  
 <form-beans >  
      <form-bean name="fileUploadForm"  
            type="com.xinglongjian.**struts**.fileupload.FileUploadForm" />  
 </form-beans>  
 <global-exceptions />  
 <global-forwards>  
  <forward name="error" path="/error/sysError.jsp"></forward>  
 </global-forwards>  
 <action-mappings>  
  <action path="/strutsfileupload" parameter="method" name="fileUploadForm"  
            type="com.xinglongjian.**struts**.fileupload.FileUploadAction" >  
              <forward name="success" path="/**struts**/success.jsp"></forward>  
        </action>  
 </action-mappings>  
</**struts**\-config>

第三步：FileUploadForm.java

public class FileUploadForm. extends ActionForm  
\{  
 private FormFile filePath; //类型为FormFile，变量filePath与页面的file名称一致。

public FormFile getFilePath()  
 \{  
  return filePath;  
 \}

public void setFilePath(FormFile filePath)  
 \{  
  this.filePath = filePath;  
 \}  
   
\}

第四步：FileUploadAction.java

public class FileUploadAction extends DispatchAction  
\{  
 /\*\*  
  \* 上传文件  
  \* @param mapping  
  \* @param form  
  \* @param request  
  \* @param response  
  \* @return  
  \* @throws Exception  
  \*/  
 public ActionForward upload(ActionMapping mapping, ActionForm. form, HttpServletRequest request, HttpServletResponse response)throws Exception  
 \{  
  FileUploadForm. fileForm=(FileUploadForm)form;  
  FormFile file=fileForm.getFilePath();  
  String realPath=this.getServlet().getServletContext().getRealPath("/fileload");  
  if(file==null)  
   return mapping.findForward("error");  
  String filename=file.getFileName();  
  int size=file.getFileSize();  
  if(size>1024\*1024)  
   return mapping.findForward("error");  
  InputStream is=null;  
  BufferedOutputStream bs=null;  
  try  
  \{  
   //get a inputstream object form. uploadFile  
   is=file.getInputStream();  
   bs=new BufferedOutputStream(new FileOutputStream(realPath+"/"+filename));  
   byte\[\] buffer=new byte\[20480\];  
   int count=0;  
   while((count=is.read())!=-1)  
    bs.write(buffer, 0, count);  
  \}  
  catch (Exception e)  
  \{  
   e.printStackTrace();  
  \}  
  finally  
  \{  
   bs.flush();  
   bs.close();  
   is.close();  
  \}  
    
  return mapping.findForward("success");  
 \}  
 /\*\*  
  \* 下载文件  
  \* @param mapping  
  \* @param form  
  \* @param request  
  \* @param response  
  \* @return  
  \* @throws Exception  
  \*/  
 public ActionForward download(ActionMapping mapping, ActionForm. form, HttpServletRequest request, HttpServletResponse response)throws Exception  
 \{  
  String path=request.getParameter("path");  
  String realPath=this.getServlet().getServletContext().getRealPath("/"+path);  
    
  File uploadFile=new File(realPath);  
  InputStream is=new FileInputStream(uploadFile);  
  OutputStream s=response.getOutputStream();  
    
  BufferedInputStream bis=new BufferedInputStream(is);  
  BufferedOutputStream bos=new BufferedOutputStream(os);  
  //弹出下载对话框的**代码**  
  response.setHeader("Content-disposition", "attachment;filename="+URLEncoder.encode(path,"utf-8"));  
  int bytesRead=0;  
  byte\[\] buffer=new byte\[8192\];  
  while((bytesRead=bis.read(buffer, 0, 8192))!=-1)  
   bos.write(buffer, 0, bytesRead);  
  bos.close();  
     is.close();  
     bis.close();  
     os.close();  
  return null;  
 \}  
\}

[include]: mailto:%@include
[http_struts_.apache.org_dtds_struts_-config_1_2.dtd]: http://struts.apache.org/dtds/struts-config_1_2.dtd