废话不多说了，直奔主题了。
需要两个jar包：
commons-fileupload.jar
Commons IO的jar包（本文使用commons-io-2.4.jar）
利用Servlet来实现文件上传。
package web.servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.util.Iterator;
import java.util.List;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
/**
* Servlet implementation class UploadServlet
*/
@WebServlet("/UploadServlet")
public class UploadServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private String uploadPath = "D:\\temp"; // 上传文件的目录
private String tempPath = "d:\\temp\\buffer\\"; // 临时文件目录
File tempPathFile;
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
try {
// Create a factory for disk-based file items
DiskFileItemFactory factory = new DiskFileItemFactory();
// Set factory constraints
factory.setSizeThreshold(4096); // 设置缓冲区大小，这里是4kb
factory.setRepository(tempPathFile);// 设置缓冲区目录
// Create a new file upload handler
ServletFileUpload upload = new ServletFileUpload(factory);
// Set overall request size constraint
upload.setSizeMax(4194304); // 设置最大文件尺寸，这里是4MB
List<FileItem> items = upload.parseRequest(request);// 得到所有的文件
Iterator<FileItem> i = items.iterator();
while (i.hasNext()) {
FileItem fi = (FileItem) i.next();
String fileName = fi.getName();
if (fileName != null) {
File fullFile = new File(fi.getName());
File savedFile = new File(uploadPath, fullFile.getName());
fi.write(savedFile);
}
}
System.out.print("upload succeed");
} catch (Exception e) {
// 可以跳转出错页面
e.printStackTrace();
}
}
public void init() throws ServletException {
File uploadFile = new File(uploadPath);
if (!uploadFile.exists()) {
uploadFile.mkdirs();
}
File tempPathFile = new File(tempPath);
if (!tempPathFile.exists()) {
tempPathFile.mkdirs();
}
}
}
jsp
<%@ page language="java" contentType="text/html; charset=ISO--" pageEncoding="utf-"%> <!DOCTYPE html PUBLIC "-//WC//DTD HTML . Transitional//EN" "http://www.w.org/TR/html/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=GB"> <title>File upload</title> </head> <body> <!-- // action="fileupload"对应web.xml中<servlet-mapping>中<url-pattern>的设置. --> <form name="myform" action="UploadServlet" method="post" enctype="multipart/form-data"> File:<br> <input type="file" name="myfile"><br> <br> <input type="submit" name="submit" value="Commit"> </form> </body> </html>
这样就能简单实现一个文件上传功能了，当然这是最最最基本的，继续研究中。
