现在一做东西就少不了，上传这个，上传那个的，那么，我的构想是，servlet去上传到服务器，也就是你指定的文件夹里面，然后，在根据用户最终确定之后，在上传到数据库里面。
环境：web项目，包：commons-fileupload-1.2.1.jar，commons-io-1.4.jar
JAVA核心代码
//这是上传
package com.upload.action;
import java.io.File;
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileItemFactory;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
public class UploadServlet extends HttpServlet {
private static final long serialVersionUID = 2121906815386996943L;
@SuppressWarnings("unchecked")
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//初始化 FileItemFactory
FileItemFactory factory = new DiskFileItemFactory();
// 初始化ServletFileUpload，可以说是一个封装好的的容器
ServletFileUpload upload = new ServletFileUpload(factory);
try {
List<FileItem> list = upload.parseRequest(request);
for (int i = 0; i < list.size(); i++) {
FileItem fileItem = list.get(i);
//根据你想要的如XX.jpg等，来截取字符串
String name = fileItem.getName().substring(fileItem.getName().lastIndexOf("\") + 1);
//保存，别说你不知道是什么。。。。
request.getSession().setAttribute(name, true);
fileItem.write(new File("d:/upload/" + name));
//这是上传图片的名字，如果只规定上传一次的话，那么直接拿这个name，如果比较多的话，那么。。。考虑中
System.out.println(name);
}
//方法一、直接放入集合中，然后循环读出放入数据库（放一个图片就立即入库）
//方法二、再写一个servlet，然后直接读出upload下的子文件夹，放入数据库（在确认这些图片的情况下，不进行改动的情况下再去入库）
//考虑到可移植性的问题，那么采取方法二
} catch (FileUploadException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
}
//这是删除
package com.upload.action;
import java.io.File;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class DeleteServlet extends HttpServlet {
private static final long serialVersionUID = -4097655768318294837L;
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
String fileName = request.getParameter("fileName");
if(fileName != null) {
boolean exist = false;
try{
exist = (Boolean) request.getSession().getAttribute(fileName);
}catch(Exception e) {
return;
}
if(exist) {
File file = new File("d:/upload/" + fileName);
if(file.exists()) {
file.delete();
}
request.getSession().removeAttribute(fileName);
}
}
}
}
jsp页面 可以说是HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>My JSP 'index.jsp' starting page</title>
<style type="text/css">
.deleteImg {
cursor: pointer;
}
#uploaddiv img {
margin-left: 20px;
}
</style>
<script type="text/javascript" src="js/jquery.js"></script>
<script type="text/javascript" src="js/ajaxupload.3.5.js"></script>
<script type="text/javascript">
var uploadIndex = 1;
$(function() {
uploadIt();
deleteFile();
});
function uploadIt() {
//最流行的jQuery，如果看不懂，那么 sorry，这里主要是上传。
$(".uploadAndNext").click(function() {
var uploadId = "#" + $(this).attr("id");
var btn = $(this);
new AjaxUpload( uploadId + "" , {
action : "UploadServlet" ,
onChange: function(file, extension){
$(uploadId + "").parent().find("input")[0].value = file;
$(uploadId + "").parent().find(".uploadAndOkImg").show().attr("src" , "images/spinner.gif");
btn.attr("disabled" , "disabled");
},
onComplete: function(file, response) {
$(uploadId + "").parent().find(".uploadAndOkImg").attr("src" , "images/ok.gif");
$(uploadId + "").parent().find(".deleteImg").attr("src" , "images/delete.gif").show();
uploadIndex++;
$("#uploaddiv").append("<div><input type='text' /><button class='uploadAndNext' id='upload" + uploadIndex + "'>浏览</button><img src='' width='20px' height='20px' class='uploadAndOkImg' style='display:none'/><img src='' width='20px' height='20px' class='deleteImg' style='display:none' alt='删除'/></div>");
uploadIt();
deleteFile();
}
});
});
}
function deleteFile() {
$("#uploaddiv .deleteImg").click(function() {
var fileName = $(this).parent().find("input").val();
var thisObj = $(this);
$.post("DeleteServlet" , {
"fileName" : fileName
},
function(data) {
thisObj.parent().remove();
}
);
});
}
//算了，还是提示一下，是jQuery的Ajax，OK?
</script>
</head>
<body>
<div id="uploaddiv">
<div><input type="text" /><button class="uploadAndNext" id="upload1">浏览</button><img src="" width="20px" height="20px" class="uploadAndOkImg" style="display: none"/><img src="" width="20px" height="20px" class="deleteImg" style="display:none;" alt="删除"/></div>
</div>
</body>
</html>
注：有点不好使，但是学习完之后，你可以自己创作。这只是个案例。
转：http://liuyang-1989xy.blog.163.com/blog/static/1687545732010111061145523/