使用javax.servlet.http.Part类上传文件
使用的是Servlet 3.0 新的特征标注（Annotaion）类描述部署，一些低版本的服务器需要使用标准依赖部署描述文件（web.xml）来部署，另外Part也是Java EE 6.0新增的类，Part是一个接口继承于javax.servlet.http，代表一部分表单项目接收来自multipart/form-data的POST的请求。
!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>上传文件</title>
</head>
<body>
<div class="container">
<form action="upload.do" method="post" enctype="multipart/form-data">
<table>
<tr>
<td><label for="file">上传文件：</label></td>
<td><input type="file" id="file" name="picture" value=""/></td>
</tr>
<tr>
<td colspan="2"><input type="submit" value="提交"/></td>
</tr>
</table>
</form>
</div>
</body>
</html>
@MultipartConfig
@WebServlet(name = "UploadServlet", urlPatterns = {"/upload.do"})
public class UploadServlet extends HttpServlet {
private String contextPath;
@Override
public void init() throws ServletException {
contextPath = getServletContext().getRealPath("/");
}
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
Part part = request.getPart("picture");
String fileName = getFileName(part);
writeTo(fileName, part);
//forward到显示
request.setAttribute("fileName", fileName);
request.getRequestDispatcher("show.jsp").forward(request, response);
}
//取得上传文件名
private String getFileName(Part part) {
String header = part.getHeader("Content-Disposition");
String fileName = header.substring(header.indexOf("filename=\"") + 10,
header.lastIndexOf("\""));
return fileName;
}
//存储文件
private void writeTo(String fileName, Part part) throws IOException, FileNotFoundException {
InputStream in = part.getInputStream();
OutputStream out = new FileOutputStream(contextPath + fileName);
byte[] buffer = new byte[1024];
int length = -1;
while ((length = in.read(buffer)) != -1) {
out.write(buffer, 0, length);
}
in.close();
out.close();
}
}
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<h1>图片显示</h1>
<a href="${fileName}">${fileName}</a>
</body>
</html>
