判断上传文件是否为图片
程序员文章站
2024-02-19 19:28:34
...
1.创建前端页面，设置表单
<html>
<head>
<title>$Title$</title>
</head>
<body>
<%=session.getAttribute("picSuffix")%>
<form action="fileselevet" enctype="multipart/form-data" method="post">
<input type="text" name="uname">
<input type="file" name="file">
<input type="submit" value="提交">
</form>
</body>
</html>
2.用servlet实现
@WebServlet("/fileselevet")
public class fileselevet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//设置编码格式
request.setCharacterEncoding("utf-8");
HttpSession session =request.getSession();
//读取磁盘工厂对象
FileItemFactory factory = new DiskFileItemFactory();
ServletFileUpload fileUpload = new ServletFileUpload(factory);
String[] suffixArr = {".jpg",".png",".gif"};
try {
List<FileItem> fileItemList = fileUpload.parseRequest(request);
for(FileItem fileItem :fileItemList){
if(fileItem.isFormField()){//是普通字段
String fieldNmae = fileItem.getFieldName();
String fieldVal = fileItem.getString();
}else {
String fieldNmae = fileItem.getFieldName();
String fieldVal = fileItem.getName();
//获取上传文件的后缀
int lastIndex = fieldVal.lastIndexOf(".");
String suffix = fieldVal.substring(lastIndex);
//判断上传文字后缀是否存在于
//数组转换为集合 这个list集合是list集合封装后的list
List<String> suffixList = Arrays.asList(suffixArr);
if(!suffixList.contains(suffix)){
session.setAttribute("picSuffix",suffixList);
response.sendRedirect("index.jsp");
return;
}
}
}
} catch (FileUploadException e) {
e.printStackTrace();
}
}
}
上一篇： Android自定义相机实现定时拍照功能
下一篇： ajax上传文件并且判断是否为空