public void downloadFiles(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
request.setCharacterEncoding("UTF-8");
String docId = new String(request.getParameter("docId").getBytes("ISO-8859-1"), "UTF-8");
String downloadType = new String(request.getParameter("downloadType").getBytes("ISO-8859-1"), "UTF-8");
Document doc = null;
try
{
doc = getFilePath(docId); //此方法获取文件的路径,这个不显示
}
catch (SQLException ex)
{
ex.printStackTrace();
}
List<Element> elements = doc.getRootElement().elements();
List<File> files = new ArrayList<File>();
int index = 0;
long fileLength = 0;
for(Element ele : elements)
{
String filePath = FormatUtil.tryGetItemText(ele, "FILE_PATH", "") + FormatUtil.tryGetItemText(ele, "FILE_NAME", "");
File file = new File(filePath);
files.add(file);
fileLength += file.length();
index++;
}
String fileName = UUID.randomUUID().toString() + ".zip";
//在服务器端创建打包下载的临时文件
String outFilePath = "C:\\" + fileName;
File file = new File(outFilePath);
//文件输出流
FileOutputStream outStream = new FileOutputStream(file);
//压缩流
ZipOutputStream toClient = new ZipOutputStream(outStream);
toClient.setEncoding("gbk");
zipFile(files, toClient);
toClient.close();
outStream.close();
this.downloadZip(file, response);
}
/**
* 压缩文件列表中的文件
* @param files
* @param outputStream
* @throws IOException
*/
public static void zipFile(List files, ZipOutputStream outputStream) throws IOException,ServletException
{
try
{
int size = files.size();
//压缩列表中的文件
for(int i = 0; i < size; i++)
{
File file = (File) files.get(i);
zipFile(file, outputStream);
}
}
catch(IOException e)
{
throw e;
}
}
/**
* 将文件写入到zip文件中
* @param inputFile
* @param outputstream
* @throws Exception
*/
public static void zipFile(File inputFile, ZipOutputStream outputstream) throws IOException,ServletException
{
try{
if(inputFile.exists())
{
if(inputFile.isFile())
{
FileInputStream inStream = new FileInputStream(inputFile);
BufferedInputStream bInStream = new BufferedInputStream(inStream);
ZipEntry entry = new ZipEntry(inputFile.getName());
outputstream.putNextEntry(entry);
final int MAX_BYTE = 10 * 1024 *1024; //最大的流为10M
long streamTotal = 0; //接受流的容量
int streamNum = 0; //流需要分开的数量
int leaveByte = 0; //文件剩下的字符数
byte[] inOutbyte; //byte数组接受文件的数据
streamTotal = bInStream.available(); //通过available方法取得流的最大字符数
streamNum = (int)Math.floor(streamTotal / MAX_BYTE); //取得流文件需要分开的数量
leaveByte = (int)streamTotal % MAX_BYTE; //分开文件之后,剩余的数量
if (streamNum > 0)
{
for(int j = 0; j < streamNum; ++j)
{
inOutbyte = new byte[MAX_BYTE];
//读入流,保存在byte数组
bInStream.read(inOutbyte, 0, MAX_BYTE);
outputstream.write(inOutbyte, 0, MAX_BYTE); //写出流
}
}
//写出剩下的流数据
inOutbyte = new byte[leaveByte];
bInStream.read(inOutbyte, 0, leaveByte);
outputstream.write(inOutbyte);
outputstream.closeEntry(); //Closes the current ZIP entry and positions the stream for writing the next entry
bInStream.close(); //关闭
inStream.close();
}
}
else
{
throw new ServletException("文件不存在!");
}
}
catch(IOException e)
{
throw e;
}
}
/**
* 下载打包的文件
* @param file
* @param response
*/
public void downloadZip(File file,HttpServletResponse response) {
try {
// 以流的形式下载文件。
BufferedInputStream fis = new BufferedInputStream(new FileInputStream(file.getPath()));
byte[] buffer = new byte[fis.available()];
fis.read(buffer);
fis.close();
// 清空response
response.reset();
OutputStream toClient = new BufferedOutputStream(response.getOutputStream());
response.setContentType("application/octet-stream");
response.setHeader("Content-Disposition", "attachment;filename=" + file.getName());
toClient.write(buffer);
toClient.flush();
toClient.close();
file.delete(); //将生成的服务器端文件删除
}
catch (IOException ex) {
ex.printStackTrace();
}
}
JAVA后台多文件打包下载
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