首先是表单的jsp文件：upload.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>文件上传</title>
</head>
<body>
<h1>文件上传</h1>
<form action="message.jsp" method="post" enctype="multipart/form-data">
选择一个文件:
<input type="file" name="uploadFile"/>
<br/><br/>
<input type="submit" value="上传"/>
</form>
</body>
</html>
上传处理的jsp文件：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>
<%
//定义上传文件的最大字节
int MAX_SIZE = 102400 * 102400;
//创建根路径的保存变量
String rootPath;
//声明文件读入类
DataInputStream in = null;
FileOutputStream fileOut = null;
//取得互联网程序的绝对地址
String realPath = request.getSession().getServletContext().getRealPath("/");
realPath = realPath.substring(0, realPath.indexOf("\out"));
// out.print(realPath);
//创建文件的保存目录
rootPath = realPath + "\web\upload\";
//取得客户端上传的数据类型
String contentType = request.getContentType();
try {
if (contentType.indexOf("multipart/form-data") >= 0) {
//读入上传数据
in = new DataInputStream(request.getInputStream());
int formDataLength = request.getContentLength();
if (formDataLength > MAX_SIZE) {
out.print("上传的字节不可以超过" + MAX_SIZE + "字节");
return;
}
//保存上传文件的数据
byte dataBytes[] = new byte[formDataLength];
int byteRead = 0;
int totalBytesRead = 0;
//上传的数据保存在byte数组里面
while (totalBytesRead < formDataLength) {
byteRead = in.read(dataBytes, totalBytesRead, formDataLength);
totalBytesRead += byteRead;
}
//根据byte数组创建字符串
String file = new String(dataBytes, "utf-8");
//取得上传数据的文件名
String saveFile = file.substring(file.indexOf("filename="") + 10);
saveFile = saveFile.substring(0, saveFile.indexOf("
"));
saveFile = saveFile.substring(saveFile.lastIndexOf("\") + 1, saveFile.indexOf("""));
int lastIndex = contentType.lastIndexOf("=");
//取得数据的分隔字符串
String boundary = contentType.substring(lastIndex + 1, contentType.length());
//创建保存路径的文件名
String fileName = rootPath + saveFile;
int pos;
pos = file.indexOf("filename = "");
pos = file.indexOf("
", pos) + 1;
pos = file.indexOf("
", pos) + 1;
pos = file.indexOf("
", pos) + 1;
int boundaryLocation = file.indexOf(boundary, pos) - 4;
//取得文件数据的开始的位置
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 + "文件已经存在.</p>");
return;
}
//检查上传文件的目录是否存在
File fileDir = new File(rootPath);
if (!fileDir.exists()) {
fileDir.mkdirs();
}
//创建文件的输出类
fileOut = new FileOutputStream(fileName);
//保存文件的数据
fileOut.write(dataBytes, startPos, (endPos - startPos));
fileOut.close();
out.print("<b>文件上传成功</b>");
} else {
String content = request.getContentType();
out.print("上传的文件类型是" + content + "类型的，请上传目录mutipart/form-data类型的文件");
}
} catch (Exception ex) {
throw new ServerException(ex.getMessage());
}
%>
</body>
</html>
