JavaWeb文件上传与处理-优快云博客

本文链接：https://blog.youkuaiyun.com/jian_aidehua/article/details/120260713

文件上传-javaweb

需要导入的jar包有：commons-fileupload-1.3.3.jar commons-io-2.6.jar

eclipse 导入jar包的看最下面

防止Commons IO导包错了，列举一下。

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

servlet

节约篇幅，导包就不显示出来，alt+ / 导包（eclipse） alt+anter(idea)

package com.xhb.controller;
@WebServlet("/Zy3_UserServlet")
public class Zy3_UserServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    public Zy3_UserServlet() {
        super();
    }

    public void register(HttpServletRequest req, HttpServletResponse resp) throws Exception {

		Map<String, String> paramList = FileUploadUtil.getParamList();// 普通表单的参数
		List<FileItem> fileList = FileUploadUtil.getFileList(); // 文件表单中的文件
		
		// 校验数据
		checkParams(req,resp,paramList,fileList);
		
		// 保存头像
		// 文件上传到本地，返回文件的UUID
		File realPathFile = new File(req.getServletContext().getRealPath("/upload")+"/"+paramList.get("name"));
		if (!realPathFile.exists()) {
			realPathFile.mkdir();
		}
		List<String> fileUUIDList = FileUploadUtil.fileUploadToLocal(req.getServletContext().getRealPath("/upload")+"/"+paramList.get("name"));
		
		HttpSession session = req.getSession();
		User user = new  User();
		user.setName(paramList.get("name"));
		user.setPassword(paramList.get("password"));
		user.setTxUUID(fileUUIDList.get(0));
		
		session.setAttribute("user", user);
		
		resp.sendRedirect("zy3_show.jsp");
    }
    	// 获取头像
    public void tx(HttpServletRequest request,HttpServletResponse response) throws IOException, Exception {
    	System.out.println("tx");
    	User user = (User)request.getSession().getAttribute("user");
    	System.out.println(user);
    	String uploadPath = req.getServletContext().getRealPath("/upload");
    	File tx = new File(uploadPath+"\\"+user.getName()+"\\"+user.getTxUUID());
    	System.out.println("tx:"+tx);
    	
    	response.setContentType("image/jpeg"); // 响应的类型是图片
    	BufferedImage image = ImageIO.read(tx);// 从本地中读取图片
		OutputStream os = response.getOutputStream();
		ImageIO.write(image, "png",os ); // 响应给客户端
		os.flush();
		os.close();
		
    }
	
    // 校验前端数据 （不符后规范，转发到页面 提示用户）
    public void checkParams(HttpServletRequest req, HttpServletResponse resp,Map<String, String> paramList,List<FileItem> fileList ) throws Exception {

    	boolean flag = true;
    	
		String name = paramList.get("name");
		String password = paramList.get("pwd");
		
		req.setAttribute("name", name);
		req.setAttribute("password", password);
		
		// 验证用户名
		if(name.length()<6 || name.length()>18 ) {
			req.setAttribute("nameErr", "纯英文字符，长度在6-18之间");
			flag = false;
		}else {req.setAttribute("nameErr", "ok");}
		for(int i=0;i<name.length();i++) {
			if(!((name.charAt(i)>='A' && name.charAt(i)<='Z')  || (name.charAt(i)>='a' && name.charAt(i)<='z'))) {
				req.setAttribute("nameErr", "纯英文字符，长度在6-18之间");
				flag = false;
				break;
			}
		}
		
		// 验证密码
		if(password.length()<6 || isNumeric(password)) {
			req.setAttribute("pwdErr", "长度必须大于6，不能是纯数字");
			flag = false;
		}else {req.setAttribute("pwdErr", "ok");}
		
		
		// 验证头像
		req.removeAttribute("txErr");
		for (FileItem fileItem : fileList) {
    		//利用File对象方便的得到文件名
			String fileName=new File(fileItem.getName()).getName();
			
			//判断文件类型
			String fileExtName = fileName.substring(fileName.lastIndexOf(".") + 1);//得到后缀
			System.out.println(fileExtName+"后缀");
			//jpg、png、<1M
			if(!(  ("jpg".equals(fileExtName)) || ("png".equals(fileExtName)) || (fileItem.getSize()<=1024*1024*1) ) ) {
				req.setAttribute("txErr", "格式为png和jpg，大小不能超过1M");
				flag = false;
			}
		}
		
		if(!flag) { // 如果数据有问题，转发
			req.getRequestDispatcher("zy3_register.jsp").forward(req, resp);
		}
		
    }
    
    // 是否是纯数字
    public boolean isNumeric(String str){
        Pattern pattern = Pattern.compile("[0-9]*");
        Matcher isNum = pattern.matcher(str);
        if( !isNum.matches() ){
            return false;
        }
        return true;
 }
  
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		// 判断是否是文件
		boolean isMultipart=ServletFileUpload.isMultipartContent(req);
    	try {
			if(isMultipart) { // 是文件
				req.setCharacterEncoding("utf-8");
				DiskFileItemFactory factory=new DiskFileItemFactory();
				ServletFileUpload fileUpload=new ServletFileUpload(factory);
			
				FileUploadUtil.parseFile(fileUpload.parseRequest(req));
				Map<String, String> paramList = FileUploadUtil.getParamList();
				
				if("register".equals(paramList.get("op"))) {
	    			register(req, resp);
	    		}else if("tx".equals(paramList.get("op"))) {
	    			tx(req, resp);
	    		}
				
			}else { // 非文件
				if("register".equals(req.getParameter("op"))) {
	    			register(req, resp);
	    		}else if("tx".equals(req.getParameter("op"))) {
	    			tx(req, resp);
	    		}
			}			
		}  catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}
}

工具类

手动封装

package com.xhb.utils;
public class FileUploadUtil {

	private static List<FileItem> fileList = null; //文件集合列
	private static Map<String, String> paramList = null; //普通表单参数列
	
	/**
	 *  文件解析 （解析成普通表单参数  与   文件） 对应两个集合
	 * @param fileItemList
	 * @throws Exception
	 */
	public static void parseFile(List<FileItem> fileItemList) throws Exception {

		fileList = new ArrayList<FileItem>();
		paramList = new HashMap<String, String>();
		
		for(FileItem item : fileItemList) {
			//判断该项是否为普通项
			if(item.isFormField()) {
				String inputName = item.getFieldName();
				String inputValue = item.getString("utf-8");
				System.out.println("表单中input项的名字(name):"+inputName);
				System.out.println("其值是:"+inputValue);
				paramList.put(inputName, inputValue);
				
			}else {
				// 是文件项
				System.out.println("该file项的名字(name):"+item.getFieldName());
				System.out.println("文件名:"+item.getName());	
				fileList.add(item);
			}
		}
	}
	
	// 文件上传到本地 上传之后返回UUID的集合，方便后面存储或者使用
	public static List<String> fileUploadToLocal(String localPaht) throws Exception {
		List<String> fileUUIDList = new ArrayList<String>(); 
		
		String fileName;// 文件名
		File saveFile;// 定义要保存的文件（路径+文件名）
		
		for (FileItem fileItem : fileList) {
			fileName = new File(fileItem.getName()).getName(); //文件名 防止浏览器的不兼容

			String uuid = UUID.randomUUID().toString(); 
			fileName =uuid+ fileName.substring(fileName.lastIndexOf("."));  // 生成唯一文件名标识
			System.out.println("fileName:"+fileName);
			
			saveFile = new File(localPaht,fileName); // 要保存的文件（路径+文件名）
			System.out.println("saveFile："+saveFile);

			fileItem.write(saveFile);		
			fileUUIDList.add(fileName);
		}
		return fileUUIDList;  // 返回唯一标识文件名的 list，便于后面操作
	}
	
	// 获取表单文件s
	public static List<FileItem> getFileList() {
		return fileList;
	}
	
	// 获取表单普通参数
	public static Map<String, String> getParamList() {
		return paramList;
	}
}

前端

注册界面

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<style type="text/css">
	span{
		color:red;
	}
</style>
<!-- 引入 layui.css -->
<link rel="stylesheet" href="//unpkg.com/layui@2.6.8/dist/css/layui.css">
 
<!-- 引入 layui.js -->
<script src="//unpkg.com/layui@2.6.8/dist/layui.js"></script>
<!--     jquery -->
<script src="https://apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js"></script>
</head>
<body>
	<!--重点  enctype="multipart/form-data" method="post"   文件表单必备-->
<form class="layui-form" action="Zy3_UserServlet" enctype="multipart/form-data" method="post">
  <div class="layui-form-item">
    <label class="layui-form-label">姓名</label>
    <div class="layui-input-inline">
      <input type="text" name="name" value="${name }" required  lay-verify="required" placeholder="请输入姓名" autocomplete="off" class="layui-input">
      <span id="s_name">${nameErr }</span>
    </div>
  </div>
  <div class="layui-form-item">
    <label class="layui-form-label">密码</label>
    <div class="layui-input-inline">
      <input type="password" name="pwd"  value="${password }" required lay-verify="required" placeholder="请输入密码" autocomplete="off" class="layui-input">
   	 <span id="s_pwd">${pwdErr } </span>
    </div>
  </div>
   
  <div class="layui-form-item">
    <label class="layui-form-label">头像：</label>
    <div class="layui-input-inline">
    	<input type="file" name="tx">
    	 <span id="s_tx">${txErr }</span>
     </div>
  </div>
  <input type="hidden" name="op" value="register">
  <input type="submit" value="注册">
</form>
</body>
</html>

显示界面

注册后，显示用户名，头像

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>

	登录成功 <br>
	${user.name } 
		<img alt="tx" src="Zy3_UserServlet?op=tx" style="width: 50px;height: 50px; border-radius: 25px;">
</body>
</html>

eclipse 导包

工程导入jar包

右击项目 --> properties

在这里插入图片描述