1.在WebRoot目录下新建一个upload文件，新建一个index.jsp和message.js文件。
1.新建一个UploadServle类;
package com.ask.upload;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
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.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
public class UploadServle extends HttpServlet {
@Override
protected void service(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {
req.setCharacterEncoding("utf-8");
String uploadPath=this.getServletContext().getRealPath("upload");
System.out.println(uploadPath);
//创建一个上传文件的工厂
DiskFileItemFactory factory=new DiskFileItemFactory();
//设置大小
factory.setSizeThreshold(100*1024);
//创建上传文件的核心对象
ServletFileUpload upload=new ServletFileUpload(factory);
upload.setHeaderEncoding("utf-8");
//判断是否是以mime协议上传
boolean flag=upload.isMultipartContent(req);
if (flag) {
try {
List<FileItem> fileItems=upload.parseRequest(req);
for (FileItem fileItem : fileItems) {
if (fileItem.isFormField()) {
//必定是普通字段
String name=fileItem.getFieldName();
String value=fileItem.getString("utf-8");
System.out.println(name+"="+value);
}else{
//必定是上传字段
String upName=fileItem.getName();
//低IE d:\e\r\e.jpg 非低IE e.jpg
int index=upName.lastIndexOf("\\");
if (index>=0) {
upName=upName.substring(upName.lastIndexOf(index+1));
}
System.out.println(upName);
InputStream is=fileItem.getInputStream();
OutputStream os=new FileOutputStream(uploadPath+"\\"+upName);
byte[] buf=new byte[1024];
int len=0;
while((len=is.read(buf))!=-1){
os.write(buf,0,len);
}
req.setAttribute("msg", "文件上传成功！");
req.getRequestDispatcher("message.jsp").forward(req, res);
}
}
} catch (FileUploadException e) {
e.printStackTrace();
req.setAttribute("msg", "文件上传失败！");
req.getRequestDispatcher("message.jsp").forward(req, res);
}
}
}
}
2.index.jsp文件代码如下:
<body>
<form action="${pageContext.request.contextPath}/up" method="post" enctype="multipart/form-data">
<table border="1" align="center">
<caption>
文件上传
</caption>
<tr>
<th>上传用户：</th>
<td>
<input type="text" name="username">
</td>
</tr>
<tr>
<th>上传文件：</th>
<td>
<input type="file" name="filename">
</td>
</tr>
<tr>
<td colspan="2" align="center">
<input type="submit" value="提交">
</td>
</tr>
</table>
</form>
</body>
3.message.jsp代码如下:
<body>
${msg }
</body>
4.xml配置如下:
<servlet>
<servlet-name>up</servlet-name>
<servlet-class>com.ask.upload.UploadServle</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>up</servlet-name>
<url-pattern>/up</url-pattern>
</servlet-mapping>
