原理:
我们知道一般的jsp程序是在wtpwebapps或者webapps文件夹下的,本教程默认在webapps下,而在服务器上的话,需要将jsp程序导出的war包放到webapps文件夹下。然后访问 域名/项目名称/文件 即可访问这个文件。这个程序是一个上传程序,将用户(其他同学好友)的war包直接上传至webapps,然后生成直接访问这个网址的链接。
闲话少叙,代码整起:
上传代码,没有UI,倒数3-4行为示例可删
upload.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
文件上传
War文件上传
如何生成war文件?看下图
结果界面 返回结果 message.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
文件上传结果
${message}
点击下方链接跳转到你的项目目录
${yoururl}
UploadServlet
package servlet;
import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
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 org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
/**
* Servlet implementation class UploadServlet
*/
@WebServlet("/upload.do")
public class UploadServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private static final String URL = "http://你的域名/";
// 上传文件存储目录
private static final String UPLOAD_DIRECTORY = "upload";
// 上传配置
private static final int MEMORY_THRESHOLD = 1024 * 1024 * 3; // 3MB
private static final int MAX_FILE_SIZE = 1024 * 1024 * 40; // 40MB
private static final int MAX_REQUEST_SIZE = 1024 * 1024 * 50; // 50MB /**
public UploadServlet() {
super();
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
response.getWriter().append("Served at: ").append(request.getContextPath());
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
* a上传数据及保存文件
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
// 检测是否为多媒体上传
if (!ServletFileUpload.isMultipartContent(request)) {
// 如果不是则停止
PrintWriter writer = response.getWriter();
writer.println("Error: 表单必须包含 enctype=multipart/form-data");
writer.flush();
return;
}
// 配置上传参数
DiskFileItemFactory factory = new DiskFileItemFactory();
// 设置内存临界值 - 超过后将产生临时文件并存储于临时目录中
factory.setSizeThreshold(MEMORY_THRESHOLD);
// 设置临时存储目录
factory.setRepository(new File(System.getProperty("java.io.tmpdir")));
ServletFileUpload upload = new ServletFileUpload(factory);
// 设置最大文件上传值
upload.setFileSizeMax(MAX_FILE_SIZE);
// 设置最大请求值 (包含文件和表单数据)
upload.setSizeMax(MAX_REQUEST_SIZE);
// 中文处理
upload.setHeaderEncoding("UTF-8");
// 构造临时路径来存储上传的文件
// 这个路径相对当前应用的目录
//String uploadPath = getServletContext().getRealPath("/") + File.separator + UPLOAD_DIRECTORY;
String uploadPath = getServletContext().getRealPath("/");
File aFile = new File(uploadPath).getParentFile();
uploadPath = aFile.toString();
// 如果目录不存在则创建
File uploadDir = new File(uploadPath);
if (!uploadDir.exists()) {
uploadDir.mkdir();
}
try {
// 解析请求的内容提取文件数据
@SuppressWarnings("unchecked")
List formItems = upload.parseRequest(request);
if (formItems != null && formItems.size() > 0) {
// 迭代表单数据
for (FileItem item : formItems) {
// 处理不在表单中的字段
if (!item.isFormField()) {
String fileName = new File(item.getName()).getName();
String filePath = uploadPath + File.separator + fileName;
File storeFile = new File(filePath);
// 在控制台输出文件的上传路径
System.out.println(filePath);
// 保存文件到硬盘
item.write(storeFile);
request.setAttribute("message",
"文件上传成功!");
fileName = fileName.substring(0,fileName.indexOf("."));
request.setAttribute("yoururl",URL + fileName);
}
}
}
} catch (Exception ex) {
request.setAttribute("message",
"错误信息: " + ex.getMessage());
}
// 跳转到 message.jsp
getServletContext().getRequestDispatcher("/admin/message.jsp").forward(
request, response);
}
}
代码第21行@WebServlet("../upload.do")需要自行修改,我的这两个jsp在WebContent下的admin文件夹下。
代码第25行 private static final String URL = "xxx";改为自己的域名
效果:(上传即可访问,有时候需要等几秒,多刷新几次)