JSP学习日记(二)　文件上传

最新推荐文章于 2025-08-26 19:56:37 发布

原创最新推荐文章于 2025-08-26 19:56:37 发布 · 870 阅读

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#jsp #random #string #file #input #import

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该博客展示了JSP实现文件上传及参数解析的代码。包含uploadfile.jsp用于选择上传文件和输入标题，uploadfile2.jsp将文件写入本地，uploadfile3.jsp通过解析临时文件获取上传内容和参数，处理文件和输入参数的上传。

uploadfile.jsp
============================================
<%@ page contentType="text/html;charset=utf-8" %>
<html>
<body>
<p>选择要上传的文件：<br>
<form action="uploadfile2.jsp" method="post" enctype="multipart/form-data">

  文件：<input type=file name="inputfilefield" size="38"/><br>
  标题：<input type="text" name="title"/>   <br>
  <input type="submit" name="uploadbutton" value="upload..."/>
</form>
</p>
</body>
</html>
　
　
uploadfile2.jsp
============================================
<%@ page contentType="text/html;charset=utf-8" %>
<%@ page import="java.io.*"%>
<html>
<body>
<%
try{
  InputStream in=request.getInputStream();
  File file=new File("G:/JspExercise/File", "uploaded.txt");
  FileOutputStream o=new FileOutputStream(file);
  byte[] b=new byte[1000];
  int n;
  while( (n=in.read(b)) != -1 ){
   o.write(b, 0, n);
  }
  o.close();
  in.close();
}
catch(IOException e){
e.printStackTrace();
}
out.println("文件已上传。");
%>
<BR>标题：<%=request.getParameter("title")%>
<BR>由于采用multiType/form-data，不能通过request.getParameter()来获得参数
<BR>这时，各种类型的参数都统一包含在inputstream中，因而只能<a href="uploadfile3.jsp">通过解析输入流来获得参数</a>

</body>
</html>
　
　
uploadfile3.jsp
============================================
<%@ page contentType="text/html;charset=utf-8" %>
<%@ page import="java.io.*"%>
<html>
<body>
<%--通过解析临时文件uploadFile来获得真正上传的内容--%>
<%
try{
  InputStream in=request.getInputStream();
  File dir = new File("G:/JspExercise/File");
  File f1=new File(dir, "uploaded.txt");
  RandomAccessFile random1=new RandomAccessFile(f1, "r");
  String formID = random1.readLine();
  if(formID == null){
   return ;
  }
  formID = formID.substring(formID.lastIndexOf('-')+1, formID.length());
  random1.seek(0);
  String line = random1.readLine();
  while(line != null && line.indexOf(formID) != -1 ){
   //处理某一个表单项
   line = random1.readLine();
   if(line != null ){
    if( line.indexOf("filename") != -1){
     //该表单项是上传的文件
     int pos = line.lastIndexOf("//");
     String fileName = line.substring(pos+1,line.length()-1);
     fileName = new String(fileName.getBytes("iso-8859-1"), "utf-8");
     File f2=new File(dir, fileName);
     RandomAccessFile random2=new RandomAccessFile(f2, "rw");
     random1.readLine();random1.readLine();          //文件指针下移两行
     long startPos = random1.getFilePointer();   //文件内容的起点
     long endPos = 0;     //文件内容的终点
     while(random1.readLine().indexOf(formID) == -1){//直到下一个表单项的起始行
      endPos = random1.getFilePointer() - 2; //不包括回车行符
     }
     //重新创建文件
     random1.seek(startPos);
     int n;
     while(startPos < endPos){
      n=random1.readByte();
      random2.write(n);
      startPos = random1.getFilePointer();
     }
     random2.close();
     out.print("<br>上传文件：" + fileName );
     out.print("（<a href='"+ fileName +"'>查看</a>）");
     random1.seek(endPos + 2);               //指向下一个表单项的起始行
     line = random1.readLine();
    }
    else{
     //该表单项是输入的参数
     String paraName = line.substring(line.indexOf("/"")+1, line.length()-1);
     random1.readLine();              //文件指针下移一行
     StringBuffer buf = new StringBuffer();
     while( (line = random1.readLine()).indexOf(formID) == -1){
      buf.append(line);
     }
     String paraValue = new String(new String(buf).getBytes("iso-8859-1"), "utf-8");
     out.print("<br>输入参数：" + paraName + "=" + paraValue);
    }
   }
  }
  random1.close();
}
catch(IOException e){
e.printStackTrace();
}
%>

</body>
</html>