1 上传下载原理
上传：
2 文件上传
①编写register.jsp
如果表单中有文件控件，则需要重新指定表单的编码方式：enctype=”multipart/form-data”
<body>
<h1>注册用户
</h1>
<form enctype="multipart/form-data" action="/StrutsFileupAndDown/register.do" method="post">
名字:
<input type="text" name="name"><br>
头像:
<input type="file" name="myphoto"><br>
<input type="submit" value="注册用户">
</form>
</body>
上传中有文件，所以myphoto类型为FormFile
public class UserForm extends ActionForm {
private String name;
private FormFile myphoto;
public String
getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public FormFile
getMyphoto() {
return myphoto;
}
public void setMyphoto(FormFile myphoto) {
this.myphoto = myphoto;
}
}
③编写Action类，上传文件
public class RegisterAction extends Action {
public ActionForward
execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response) {
UserForm userForm = (UserForm) form;
String name = userForm.getName();
FormFile formFile = userForm.getMyphoto();
String filename = formFile.getFileName();
int filesize = formFile.getFileSize();
InputStream is =
null;
OutputStream os =
null;
try {
is = formFile.getInputStream();
String filepath =
this.getServlet().getServletContext().getRealPath(
"/files");
os =
new FileOutputStream(filepath+
"\\"+MyTools.getNewFileName(filename));
int len =
0;
byte []bytes =
new byte[
1024];
while((len=is.read(bytes))>
0) {
os.write(bytes,
0, len);
}
}
catch (Exception e) {
e.printStackTrace();
return mapping.findForward(
"err");
}
finally {
try {
is.close();
os.close();
}
catch (Exception e) {
e.printStackTrace();
}
}
System.out.println(filename +
" " + filesize);
return mapping.findForward(
"ok");
}
}
④文件重名覆盖问题
编写工具类，生成一个不重复的文件名
public class MyTools {
public static String
getNewFileName(String filename) {
String uuid = UUID.randomUUID().toString();
int beginIndex = filename.lastIndexOf(
".");
String newfilename = uuid+filename.substring(beginIndex);
return newfilename;
}
public static String
getFileName(String fName) {
fName = fName.trim();
String fileName = fName.substring(fName.lastIndexOf(
"\\")+
1);
return fileName;
}
public static ArrayList<String>
getFiles(String path) {
ArrayList<String> files =
new ArrayList<String>();
File file =
new File(path);
File[] tempList = file.listFiles();
for (
int i =
0; i < tempList.length; i++) {
if (tempList[i].isFile()) {
files.add(MyTools.getFileName(tempList[i].toString()));
}
if (tempList[i].isDirectory()) {
}
}
return files;
}
}
⑤中文标题文件上传失败问题
使用过滤器：http://blog.csdn.net/u013943420/article/details/71036669#t7
3 文件下载
①下载时，需要显示文件名称、上传人名，因此需要将信息保存到数据库中。
②展示已上传文件
public class UserListAction extends Action {
public ActionForward
execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response) {
String path =
this.getServlet().getServletContext().getRealPath(
"/files");
ArrayList<String> files = MyTools.getFiles(path);
request.setAttribute(
"userlist", files);
return mapping.findForward(
"showUsers");
}
}
showUserList.jsp显示文件列表
<body>
<h1>用户列表
</h1> <br>
<c:forEach items="${userlist}" var="filename">
${filename}
<img src="/StrutsFileupAndDown/files/${filename}" width="50px" /><a href="/StrutsFileupAndDown/downloadFile.do?filename=${filename }">点击下载
</a><br>
</c:forEach>
</body>
③编写Action，下载文件
public class DownloadFileAction extends Action {
public ActionForward
execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response) {
String filename = request.getParameter(
"filename");
response.setContentType(
"text/html;charset=utf-8");
String filterFilename;
try {
filterFilename = URLEncoder.encode(filename,
"utf-8");
response.setHeader(
"Content-Disposition",
"attachment; filename="+filterFilename);
}
catch (Exception e1) {
e1.printStackTrace();
}
String filepath =
this.getServlet().getServletContext().getRealPath(
"/files");
String fileFullPath = filepath +
"\\" + filename;
FileInputStream fis =
null;
OutputStream os =
null;
byte []buffer =
new byte[
1024];
int len =
0;
try {
fis =
new FileInputStream(fileFullPath);
os = response.getOutputStream();
while((len=fis.read(buffer))>
0) {
os.write(buffer,
0, len);
}
}
catch (Exception e) {
e.printStackTrace();
}
finally {
try {
os.close();
fis.close();
}
catch (Exception e) {
e.printStackTrace();
}
}
System.out.println(filepath + filename);
return mapping.findForward(
"goback");
}
}
