jsp上传文件案例（有源码）

﹏ヽ暗。殇╰゛Y 2022-06-15 09:06 202阅读 0赞

#### 前言 ####

这两天做上传的功能，趁着端午节的时间在家里做了一个上传的案例。今天写个博客记录一下！
    说明：
        1.项目使用myeclipse开发工具
        2.项目的源码的压缩格式是7z,可以下载一个7z压缩工具解压

#### 知识点一：准备工作 ####

1.需要引入jar包---这里使用了apache的包
         commons-fileupload-1.2.2.jar
         commons-io-2.0.1.jar
     2.前台使用的js文件---我使用的是ajax提交的表单
         jquery-3.2.1.js
         jquery.form.js

##### 知识点二：项目中的知识点： #####

1. java操作文件知识
    2. java流相关知识
    3. ajax提交表单
    4. servlet知识
    5. filter知识

#### 前台页面： ####

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
    <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %>
    
    <!DOCTYPE HTML >
    <html>
      <head>
        <base href="<%=basePath%>">
         
        <meta charset="UTF-8">  
        <title>上传demo</title>
        <script type="text/javascript" src="static/js/jquery-3.2.1.js"></script>
        <script type="text/javascript" src="http://malsup.github.io/jquery.form.js"></script>
        
    
        <script type="text/javascript"> $(function(){ //给 “使用ajax上传” 按钮绑定点击事件 $("#uploadButton").on("click",function(){ $("#uploatForm").ajaxSubmit({ beforeSubmit:function(){ //提交前调用 //alert('准备提交表单了'); }, success:function(data){ //成功调用 //alert("提交成功了"); if(typeof(data) == "string"){ data = eval('(' + data + ')');;//将返回的json字符串转换为json对象 alert(data.message); } } }); }); }); </script>
      </head>
    
      <body>
            <br>
            <br>
            <form action="upload" method="post" id="uploatForm" enctype="multipart/form-data">
                <input type="file" name="upload" /><span style="color:red;font-size:13px">不能超过4M</span>
                <br>
                  <input type="submit" value="上传(请使用下面的ajax上传---同步上传也可以使用)" disabled="disabled"/>
                    <br>
                 <input type="button" value="使用ajax上传" id="uploadButton" >
            </form>
      </body>
    </html>

##### 后台代码： #####

一、servlet代码：

package cn.cupcat.controller;
    
    import java.io.File;
    import java.io.IOException;
    import java.sql.Timestamp;
    import java.text.SimpleDateFormat;
    import java.util.Iterator;
    import java.util.List;
    import java.util.UUID;
    
    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;
    
    import cn.cupcat.util.UploadUtil;
    
    public class UploadController extends HttpServlet { 
    
        /** * */
        private static final long serialVersionUID = 1L;
    
    
        public static String uploadPath = "D:\\upload";
        File repository;
    
    
    
        @Override
        protected void doPost(HttpServletRequest request, HttpServletResponse response)
                throws ServletException, IOException {
    
    
            System.out.println("我进入了post方法！");
            //返回客户端消息
            String resultMessage = "";
    
    
    
            DiskFileItemFactory fileFactory = new DiskFileItemFactory();
            //设置缓冲区大小 这里是4KB （单位是B 字节）
            fileFactory.setSizeThreshold(4096);
            //设置缓存
            fileFactory.setRepository(repository);
    
            ServletFileUpload servletFileUpload = new ServletFileUpload(fileFactory);
            //设置文件上传的大小这里是4M 
            servletFileUpload.setFileSizeMax(4194304);
    
            try {
                //得到上传文件列表
                List<FileItem> fileItem = servletFileUpload.parseRequest(request);
    
                Iterator<FileItem> iterator = fileItem.iterator();
                //得到保存路径
                File saveDir = UploadUtil.getSavePath(request);
    
    
                while(iterator.hasNext()){
    
                    FileItem file = iterator.next();
                    if(file != null){
                        String fileName = file.getName();   
                        if(fileName != null){
                            //System.out.println("上传文件的没有转码的文件名为："+fileName);
    
                            //构建本地文件
                            File saveFile = new File(saveDir,UploadUtil.getSaveFileName(fileName));
                            file.write(saveFile);
                            resultMessage = UploadUtil.getResponseResult(200, "上传成功！");
                        }else{
                            System.out.println("上传失败！");
                            resultMessage = UploadUtil.getResponseResult(300, "请选择上传文件，上传失败！");
                        }
                    }
                }
    
                System.out.println("文件上传结束 ！");
            } catch (FileUploadException e) {
                resultMessage = UploadUtil.getResponseResult(300, "文件上传错误，上传失败！");
                e.printStackTrace();
            } catch (Exception e) {
                e.printStackTrace();
                resultMessage = UploadUtil.getResponseResult(300, "文件上传错误，上传失败！");
            }
    
            response.getWriter().print(resultMessage);//返回客户端 resultMessage
    
        }
    
    
    
        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp)
                throws ServletException, IOException {
    
            this.doPost(req, resp);
    
        }
    
    
    
    
    }

二、filter代码：—主要作用是设置编码

package cn.cupcat.filter;
    
    import java.io.IOException;
    
    import javax.servlet.Filter;
    import javax.servlet.FilterChain;
    import javax.servlet.FilterConfig;
    import javax.servlet.ServletException;
    import javax.servlet.ServletRequest;
    import javax.servlet.ServletResponse;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    public class UnicodeFilter implements Filter{ 
    
        @Override
        public void destroy() {
    
    
        }
    
        @Override
        public void doFilter(ServletRequest arg0, ServletResponse arg1,
                FilterChain arg2) throws IOException, ServletException {
            if(arg0 instanceof HttpServletRequest){
                System.out.println("进入了过滤器");
                HttpServletRequest request = (HttpServletRequest)arg0;
                request.setCharacterEncoding("UTF-8"); //设置编码，防止后台得到中文乱码
            }
            if (arg1 instanceof HttpServletResponse){
                HttpServletResponse response = (HttpServletResponse)arg1;
                response.setCharacterEncoding("UTF-8");//设置编码，防止返回客户端乱码
            }
            arg2.doFilter(arg0, arg1);
        }
    
        @Override
        public void init(FilterConfig arg0) throws ServletException {
    
        }
    
    }

工具类：

package cn.cupcat.util;
    
    import java.io.File;
    import java.sql.Timestamp;
    import java.text.SimpleDateFormat;
    import java.util.UUID;
    
    import javax.servlet.http.HttpServletRequest;
    
    public class UploadUtil { 
    
        // 产生32位UUID
        public static String getUUID32() {
            return UUID.randomUUID().toString().replace("-", "");
        }
    
    
        // 获得服务器存储文件名,格式为： 32位UUID+"_"+ fileName
        public static String getSaveFileName(String fileName) {
    
            if (fileName != null && fileName.length() > 0)
                return getUUID32() + "_" + fileName;
    
            return "";
    
        }
    
        // 获得上传保存路径 -----这里是模拟的
        public static File getSavePath(HttpServletRequest request) {
    
            String date = formatDate(new Timestamp(System.currentTimeMillis()),
                    "yyyyMMdd");// 当前日期
            String moduls = "upload";// 模块名（这里假设模块名为：upload）
            String username = "A12346579";// 用户名(这里模拟用户名为：A12346579)
    
            String relativePath = File.separatorChar + "WEB-INF"
                    + File.separatorChar + "attachment" + File.separatorChar
                    + moduls + File.separatorChar + username + File.separatorChar
                    + date; //
    
    
            String absolutePath = request.getSession().getServletContext()
                    .getRealPath(relativePath);
    
    
            File dir = new File(absolutePath);
            if (!dir.exists())// 如果文件家不存在，就创建
                dir.mkdirs();
    
            return dir;
        }
    
        // 格式化时间
        public static String formatDate(Timestamp timestamp, String format) {
    
            return new SimpleDateFormat(format).format(timestamp);
        }
    
        //这里为了简单，没有引入处理json的包，这是模拟json数据
        public static String getResponseResult(int status,String message){
    
            return  "{status: "+status+",message: '"+message+"'}";
        }
    
    }

web.xml文件代码：

<?xml version="1.0" encoding="UTF-8"?>
    <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
      <display-name>upload_demo</display-name>
    
    
      <servlet>
            <servlet-name>upload</servlet-name>
            <servlet-class>cn.cupcat.controller.UploadController</servlet-class>
      </servlet>
      <servlet-mapping>
            <servlet-name>upload</servlet-name>
            <url-pattern>/upload</url-pattern>
      </servlet-mapping>
      
    
      <filter>
            <filter-name>unicode</filter-name>
            <filter-class>cn.cupcat.filter.UnicodeFilter</filter-class>
      </filter>
      <filter-mapping>
            <filter-name>unicode</filter-name>
                
            <servlet-name>upload</servlet-name> 
      </filter-mapping>
    
    
    
    
      <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.htm</welcome-file>
        <welcome-file>index.jsp</welcome-file>
        <welcome-file>default.html</welcome-file>
        <welcome-file>default.htm</welcome-file>
        <welcome-file>default.jsp</welcome-file>
      </welcome-file-list>
    </web-app>

#### 知识点三：项目中的注意点： ####

1.项目中为了简单，没有使用json的工具类，而是而是自己写的字符串返回客户端
    2.项目中上传文章的存放路径问题，请看UploadUtil.java中的方法

#### 知识点四：文件的源码 ####

文件的下载地址：[http://download.csdn.net/detail/xinghuo0007/9855550][http_download.csdn.net_detail_xinghuo0007_9855550]

说明：如果有什么不足的地方，大家可以一起交流！

[http_download.csdn.net_detail_xinghuo0007_9855550]: http://download.csdn.net/detail/xinghuo0007/9855550