java中文件的上传与下载

文件上传:

upload.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<form action="upload" method="post" enctype="multipart/form-data">
		
		File: <input type="file" name="file"/>
		<input type="submit" value="Submit"/>
		
	</form>
</body>
</html>

Servlet: upload.java

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		DiskFileItemFactory factory = new DiskFileItemFactory();
		factory.setSizeThreshold(1024 * 500);
		File tempDirectory = new File("d:\\tempDirectory");
		factory.setRepository(tempDirectory);

		ServletFileUpload upload = new ServletFileUpload(factory);

		upload.setSizeMax(1024 * 1024 * 5);
		try {
			List<FileItem> /* FileItem */items = upload.parseRequest(request);
			System.out.println(items);
			// 2. 遍历 items:
			for (FileItem item : items) {
				// 若是一个一般的表单域, 打印信息
				if (item.isFormField()) {
					String name = item.getFieldName();
					String value = item.getString();
					System.out.println(name + ": " + value);	
				}
				// 若是文件域则把文件保存到 d:\\files 目录下.
				else {
					String fieldName = item.getFieldName();
					String fileName = item.getName();
					String contentType = item.getContentType();
					long sizeInBytes = item.getSize();
					
					File filename=new File(fileName);
				 fileName=filename.getName();
					System.out.println(filename.getName());
					System.out.println(contentType);
					System.out.println(sizeInBytes);
		
					InputStream in = null;
					try {
						in = item.getInputStream();
					} catch (IOException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
					byte[] buffer = new byte[1024];
					int len = 0;

				String	fileName1 = "d:\\files\\" + fileName;
					System.out.println(fileName1);			

					OutputStream out = null;
					try {
						out = new FileOutputStream(fileName1);
					} catch (FileNotFoundException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}

					try {
						while ((len = in.read(buffer)) != -1) {
							out.write(buffer, 0, len);
						}
					} catch (IOException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}

					try {
						out.close();
					} catch (IOException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
					try {
						in.close();
					} catch (IOException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
				}
			}

		} catch (FileUploadException e) {
			e.printStackTrace();
		}	

	}

文件下载:

download.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>

	<a href="download">download</a>

</body>
</html>

Servlet: download.java

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		response.setContentType("application/x-msdownload"); 
		
		String fileName = "服务器.txt";
		response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8"));
		
		OutputStream out = response.getOutputStream();
		String pptFileName = "d:\\files\\服务器.txt";
		
		InputStream in = new FileInputStream(pptFileName);
		
		byte [] buffer = new byte[1024];
		int len = 0;
		
		while((len = in.read(buffer)) != -1){
			out.write(buffer, 0, len);
		}
		
		in.close();
	
	}

java中文件的上传与下载

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