The first is the jsp file of the form: upload.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>File upload</title>
</head>
<body>
<h1>File upload</h1>
<form action="message.jsp" method="post" enctype="multipart/form-data">
Choose a file:
<input type="file" name="uploadFile"/>
<br/><br/>
<input type="submit" value="上传"/>
</form>
</body>
</html>
Upload the processed jsp file: message.jsp:
<%--
Created by IntelliJ IDEA.
User: DELL
Date: 2018/4/20
Time: 14:10
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page import="java.io.*,java.util.*,javax.servlet.*,javax.servlet.http.*" %>
<%@ page import="java.rmi.ServerException" %>
<html>
<head>
<title></title>
</head>
<body>
<%
//Define the maximum bytes of the uploaded file
int MAX_SIZE = 102400 * 102400;
//Create a save variable for the root path
String rootPath;
//declaration file read into class
DataInputStream in = null;
FileOutputStream fileOut = null;
//Get the absolute address of the Internet program
String realPath = request.getSession().getServletContext().getRealPath("/");
realPath = realPath.substring(0, realPath.indexOf("\\out"));
// out.print(realPath);
//Create a directory to save the file
rootPath = realPath + "\\web\\upload\\";
//Get the data type uploaded by the client
String contentType = request.getContentType();
try {
if (contentType.indexOf("multipart/form-data") >= 0) {
//read upload data
in = new DataInputStream(request.getInputStream());
int formDataLength = request.getContentLength();
if (formDataLength > MAX_SIZE) {
out.print("Uploaded bytes cannot exceed" + MAX_SIZE + "bytes");
return;
}
// save the data of the uploaded file
byte dataBytes[] = new byte[formDataLength];
int byteRead = 0;
int totalBytesRead = 0;
//The uploaded data is stored in the byte array
while (totalBytesRead < formDataLength) {
byteRead = in.read(dataBytes, totalBytesRead, formDataLength);
totalBytesRead + = byteRead;
}
//create string from byte array
String file = new String(dataBytes, "utf-8");
//Get the filename of the uploaded data
String saveFile = file.substring(file.indexOf("filename=\"") + 10);
saveFile = saveFile.substring(0, saveFile.indexOf("\n"));
saveFile = saveFile.substring(saveFile.lastIndexOf("\\") + 1, saveFile.indexOf("\""));
int lastIndex = contentType.lastIndexOf("=");
//get the delimited string of data
String boundary = contentType.substring(lastIndex + 1, contentType.length());
//Create a filename for the save path
String fileName = rootPath + saveFile;
int pos;
pos = file.indexOf("filename = \"");
pos = file.indexOf("\n", pos) + 1;
pos = file.indexOf("\n", pos) + 1;
pos = file.indexOf("\n", pos) + 1;
int boundaryLocation = file.indexOf(boundary, pos) - 4;
//Get the starting position of the file data
int startPos = ((file.substring(0, pos)).getBytes()).length;
int endPos = ((file.substring(0, boundaryLocation)).getBytes()).length;
File checkFile = new File(fileName);
if (checkFile.exists()) {
out.println("<p>" + saveFile + "The file already exists.</p>");
return;
}
//Check if the directory where the uploaded file exists
File fileDir = new File(rootPath);
if (!fileDir.exists()) {
fileDir.mkdirs();
}
//create the output class of the file
fileOut = new FileOutputStream(fileName);
// save the data of the file
fileOut.write(dataBytes, startPos, (endPos - startPos));
fileOut.close();
out.print("<b>File uploaded successfully</b>");
} else {
String content = request.getContentType();
out.print("The uploaded file is of type " + content + ", please upload a file of type mutipart/form-data");
}
} catch (Exception ex) {
throw new ServerException(ex.getMessage());
}
%>
</body>
</html>
