}
四：文件上傳示例：
JSP代碼：
servlet後台代碼：
public class UploadServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
PrintWriter pout = response.getWriter();
try {
// 得到存放上傳文件的真實路徑
String storePath = getServletContext()
.getRealPath("/WEB-INF/files");
// 設置環境
DiskFileItemFactory factory = new DiskFileItemFactory();
factory.setRepository(new File(getServletContext().getRealPath("/temp")));//設置臨時存放目錄
// 判斷一下form是否是enctype=multipart/form-data類型的
boolean isMultipart = ServletFileUpload.isMultipartContent(request);
if (!isMultipart) {
System.out.println("大傻鳥");
return;
}
// ServletFileUpload核心類
ServletFileUpload upload = new ServletFileUpload(factory);
// upload.setProgressListener(new ProgressListener() {
// //pBytesRead：當前以讀取到的字節數
// //pContentLength：文件的長度
// //pItems:第幾項
// public void update(long pBytesRead, long pContentLength,
// int pItems) {
// System.out.println("已讀取："+pBytesRead+",文件大小："+pContentLength+",第幾項："+pItems);
// }
//
// });
upload.setFileSizeMax(4 * 1024 * 1024);// 設置單個上傳文件的大小
upload.setSizeMax(6 * 1024 * 1024);// 設置總文件大小
// 解析
List items = upload.parseRequest(request);
for (FileItem item : items) {
if (item.isFormField()) {
// 普通字段
String fieldName = item.getFieldName();
String fieldValue = item.getString("UTF-8");
System.out.println(fieldName + "=" + fieldValue);
} else {
// 得到MIME類型
String mimeType = item.getContentType();
// 只允許上傳圖片
if(mimeType.startsWith("image")){
// 上傳字段
InputStream in = item.getInputStream();
// 上傳的文件名
String fileName = item.getName();// C:\Documents and
if(fileName==null||"".equals(fileName.trim())){
continue;
}
// Settings\wzhting\妗岄潰\a.txt
// a.txt
fileName = fileName
.substring(fileName.lastIndexOf("\\") + 1);// a.txt
fileName = UUID.randomUUID() + "_" + fileName;
System.out.println(request.getRemoteAddr()+"=============="+fileName);
// 構建輸出流
// 打散存儲目錄
String newStorePath = makeStorePath(storePath, fileName);// 根據
// /WEB-INF/files和文件名，創建一個新的存儲路徑
// /WEB-INF/files/1/12
String storeFile = newStorePath + "\\" + fileName;// WEB-INF/files/1/2/sldfdslf.txt
OutputStream out = new FileOutputStream(storeFile);
byte b[] = new byte[1024];
int len = -1;
while ((len = in.read(b)) != -1) {
out.write(b, 0, len);
}
out.close();
in.close();
item.delete();//刪除臨時文件
}
}
}
} catch (org.apache.commons.fileupload.FileUploadBase.FileSizeLimitExceededException e) {
// 單個文件超出大小時的異常
pout.write("單個文件大小不能超出4M");
} catch (org.apache.commons.fileupload.FileUploadBase.SizeLimitExceededException e) {
// 總文件超出大小時的異常
pout.write("總文件大小不能超出6M");
} catch (Exception e) {
e.printStackTrace();
}
}
// 根據 /WEB-INF/files和文件名，創建一個新的存儲路徑 /WEB-INF/files/1/12
private String makeStorePath(String storePath, String fileName) {
int hashCode = fileName.hashCode();
int dir1 = hashCode & 0xf;// 0000~1111：整數0~15共16個
int dir2 = (hashCode & 0xf0) >> 4;// 0000~1111：整數0~15共16個
String path = storePath + "\\" + dir1 + "\\" + dir2; // WEB-INF/files/1/12
File file = new File(path);
if (!file.exists())
file.mkdirs();
return path;
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
五：文件下載
1.顯示上述存儲所有的照片信息:
//顯示所有上傳的文件，封裝到域對象中，交給jsp去顯示
public class ShowAllFilesServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
Map map = new HashMap();//key：UUID文件名；value：老文件名
//得到存儲文件的根目錄
String storePath = getServletContext().getRealPath("/WEB-INF/files");
//遞歸遍歷其中文件
File file = new File(storePath);
treeWalk(file,map);
//交給JSP去顯示：如何封裝數據.用Map封裝。key：UUID文件名；value：老文件名
request.setAttribute("map", map);
request.getRequestDispatcher("/listFiles.jsp").forward(request, response);
}
//遍歷/WEB-INF/files所有文件，把文件名放到map中
private void treeWalk(File file, Map map) {
if(file.isFile()){
//是文件
String uuidName = file.getName();// UUID_a_a.txt//真實文件名
String oldName = uuidName.substring(uuidName.indexOf("_")+1);
map.put(uuidName, oldName);
}else{
//是一個目錄
File[] fs = file.listFiles();
for(File f:fs){
treeWalk(f,map);
}
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
} 2.顯示所有文件listFiles.jsp頁面中的內容：
本站有以下好圖片
${me.value} 下載
3.文件下載DownloadServlet：
public class DownloadServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
OutputStream out = response.getOutputStream();
String filename = request.getParameter("filename");//get請求方式
filename = new String(filename.getBytes("ISO-8859-1"),"UTF-8");//中文編碼
//截取老文件名
String oldFileName = filename.split("_")[1];
//得到存儲路徑
String storePath = getServletContext().getRealPath("/WEB-INF/files");
//得到文件的全部路徑
String filePath = makeStorePath(storePath, filename)+"\\"+filename;
//判斷文件是否存在
File file = new File(filePath);
if(!file.exists()){
out.write("對比起！你要下載的文件可能已經不存在了".getBytes("UTF-8"));
return;
}
InputStream in = new FileInputStream(file);
//通知客戶端以下載的方式打開
response.setHeader("Content-Disposition", "attachment;filename="+URLEncoder.encode(oldFileName, "UTF-8"));
byte[] b = new byte[1024];
int len = -1;
while((len=in.read(b))!=-1){
out.write(b, 0, len);
}
in.close();
out.write("下載成功".getBytes("UTF-8"));
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
private String makeStorePath(String storePath, String fileName) {
int hashCode = fileName.hashCode();
int dir1 = hashCode & 0xf;// 0000~1111：整數0~15共16個
int dir2 = (hashCode & 0xf0) >> 4;// 0000~1111：整數0~15共16個
String path = storePath + "\\" + dir1 + "\\" + dir2; // WEB-INF/files/1/12
File file = new File(path);
if (!file.exists())
file.mkdirs();
return path;
}
}
