效果图如下：
代码：
注意：需要jar包：commons-fileupload-1.2.1.jar 和 commons-io-1.4.jar
index.jsp
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>添加图片</title>
<script type="text/javascript">
//打开上传页面
function openUpload(){
var win = window.showModalDialog("/upload.jsp","","dialogWidth:300px;dialogHeight:200px;scroll:no;status:no");
if(win != null){
document.getElementById("photo_id").value = win;
document.getElementById("img_id").src = "/"+win;
}
}
</script>
</head>
<body>
<h5>添加图片</h5><hr/>
<p>
上传图片：
<label>
<input type="hidden" id="photo_id" name="photo" value="images/default.gif">
<input type="button" onclick="openUpload()" value="上传图片"/><br/>
<img id="img_id" alt="" src="/images/default.gif" width="200px" height="200px">
</label>
</p>
</body>
</html>
upload.jsp
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=GBK">
<meta http-equiv="pragma" content="no-cache" />
<span style="color: #ff0000;"><base target="_self"></span>
<title>图片上传</title>
</head>
<body>
<h5>图片上传</h5><hr/>
<p style="color: red">${requestScope.errorMsg}</p>
<form id="form1" name="form1" action="/servlet/Upload" method="post" enctype="multipart/form-data">
<div>注:图片大小最大不能超过3M!</div>
<div>
<input type="file" name="file_upload"/>
<input type="submit" value="上传"/>
</div>
</form>
</body>
</html>
Upload.java 中的主要代码：
public class Upload extends HttpServlet {
private String uploadPath = "aa/upload/"; // 上传文件的目录
private String tempPath = "aa/uploadtmp/"; // 临时文件目录
private String serverPath = null;
private int sizeMax = 3;//图片最大上限
private String[] fileType = new String[]{".jpg",".gif",".bmp",".png",".jpeg",".ico"};
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
response.setCharacterEncoding("utf-8"); //设置编码，方式返回的中文乱码
serverPath = getServletContext().getRealPath("/").replace("\\", "/");
//Servlet初始化时执行,如果上传文件目录不存在则自动创建
if(!new File(serverPath+uploadPath).isDirectory()){
new File(serverPath+uploadPath).mkdirs();
}
if(!new File(serverPath+tempPath).isDirectory()){
new File(serverPath+tempPath).mkdirs();
}
DiskFileItemFactory factory = new DiskFileItemFactory();
factory.setSizeThreshold(5*1024); //最大缓存
factory.setRepository(new File(serverPath+tempPath));//临时文件目录
ServletFileUpload upload = new ServletFileUpload(factory);
upload.setSizeMax(sizeMax*1024*1024);//文件最大上限
String filePath = null;
try {
List<FileItem> items = upload.parseRequest(request);//获取所有文件列表
for (FileItem item : items) {
//获得文件名，这个文件名包括路径
if(!item.isFormField()){
//文件名
String fileName = item.getName().toLowerCase();
if(fileName.endsWith(fileType[0])||fileName.endsWith(fileType[1])||fileName.endsWith(fileType[2])||fileName.endsWith(fileType[3])||fileName.endsWith(fileType[4])||fileName.endsWith(fileType[5])){
String uuid = UUID.randomUUID().toString();
filePath = serverPath+uploadPath+uuid+fileName.substring(fileName.lastIndexOf("."));
item.write(new File(filePath));
PrintWriter pw = response.getWriter();
pw.write("<script>alert(‘上传成功‘);window.returnValue=‘"+uploadPath+uuid+fileName.substring(fileName.lastIndexOf("."))+"‘;window.close();</script>");
pw.flush();
pw.close();
}else{
request.setAttribute("errorMsg", "上传失败,请确认上传的文件存在并且类型是图片!");
request.getRequestDispatcher("/upload.jsp").forward(request,response);
}
}
}
} catch (Exception e) {
e.printStackTrace();
request.setAttribute("errorMsg", "上传失败,请确认上传的文件大小不能超过"+sizeMax+"M");
request.getRequestDispatcher("/upload.jsp").forward(request,response);
}
}
}
<p style="color: red">${requestScope.errorMsg}</p>
表示变量的作用域，一共4种。
pageScope: 表示变量只能在本页面使用。
requestScope:表示变量能在本次请求中使用。
sessionScope:表示变量能在本次会话中使用。
applicationScope:表示变量能在整个应用程序中使用。
时间： 2024-11-13 07:55:26