[JavaScript知识库] 【无标题】javaweb文件上传与下载

开发: C++知识库 Java知识库 JavaScript Python PHP知识库人工智能区块链大数据移动开发嵌入式开发工具数据结构与算法开发测试游戏开发网络协议系统运维
教程: HTML教程 CSS教程 JavaScript教程 Go语言教程 JQuery教程 VUE教程 VUE3教程 Bootstrap教程 SQL数据库教程 C语言教程 C++教程 Java教程 Python教程 Python3教程 C#教程
数码: 电脑笔记本显卡显示器固态硬盘硬盘耳机手机 iphone vivo oppo 小米华为单反装机图拉丁

-> JavaScript知识库 -> 【无标题】javaweb文件上传与下载 -> 正文阅读

[JavaScript知识库]【无标题】javaweb文件上传与下载

构建数据库filetest：包含文件名称及路径

SET FOREIGN_KEY_CHECKS=0;

-- ----------------------------
-- Table structure for file
-- ----------------------------
DROP TABLE IF EXISTS `file`;
CREATE TABLE `file` (
  `id` int(5) NOT NULL AUTO_INCREMENT,
  `filename` varchar(50) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,
  `filepath` varchar(255) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=17 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of file
-- ----------------------------

项目目录结构:

文件上传页面index.jsp：

<%@ page contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<!DOCTYPE html>
<html>
<head>
  <title>文件上传与下载</title>
<%--  使用cnd加速--%>
  <script src="http://libs.baidu.com/jquery/2.0.0/jquery.min.js"></script>
  <%
    String proPath = request.getServletContext().getContextPath();
  %>
  <script type="text/javascript">
<%--    设置input宽度--%>
    $(function (){
      $("[type=file]").each(function (){
        $(this).css("width","150px");
      })
    })
    function toDown(){
      window.location.href = '<%=proPath %>/filelist';
    }
  </script>
</head>
<body>
<form action="<%=proPath %>/upfile" method="post" enctype="multipart/form-data">
  文件1：<input type="file" name="file1"/><br/>
  文件2：<input type="file" name="file2"/><br/>
  文件3：<input type="file" name="file3"/><br/>
  <input type="submit" value="上传">
  <div style="color: red;">${requestScope.msg}</div>
</form>
<button type="button" onclick="toDown();">去下载</button>
</body>
</html>

文件列表页面filelist.jsp：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>文件列表</title>
    <%
//        String path = request.getContextPath();
//        String proPath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path;
        String proPath = request.getServletContext().getContextPath();
    %>
</head>
<body>
<c:forEach var="file" items="${requestScope.filelist}">
    文件名：<c:out value="${file.filename}"/>&nbsp;&nbsp;
    <a href="<%=proPath %>/downfile?id=<c:out value="${file.id}"/>&filename=<c:out value="${file.filename}"/>">下载</a><br>
</c:forEach>
<font>${requestScope.msg}</font>
</body>
</html>

javabean:

package com.web.beans;

public class FileTest {
    private int id;
    private String filename;
    private String filepath;

    public FileTest() {
    }

    public FileTest(int id,String filename, String filepath) {
        this.id = id;
        this.filename = filename;
        this.filepath = filepath;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getFilename() {
        return filename;
    }

    public void setFilename(String filename) {
        this.filename = filename;
    }

    public String getFilepath() {
        return filepath;
    }

    public void setFilepath(String filepath) {
        this.filepath = filepath;
    }

    @Override
    public String toString() {
        return "FileTest{" +
                "id=" + id +
                ", filename='" + filename + '\'' +
                ", filepath='" + filepath + '\'' +
                '}';
    }
}

c3p0配置：

<?xml version="1.0" encoding="UTF-8" ?>
<c3p0-config>
    <named-config name="test">
        <property name="user">root</property>
        <property name="password">fuyou</property>
        <property name="jdbcUrl">jdbc:mysql://119.91.83.99:3306/filetest?characterEncoding=UTF-8</property>
        <property name="driverClass">com.mysql.jdbc.Driver</property>
<!--        连接不够时的增长-->
        <property name="acquireIncrement">5</property>
        <!-- 初始化数据库连接池时连接的数量 -->
        <property name="initialPoolSize">20</property>
        <!-- 数据库连接池中的最大的数据库连接数 -->
        <property name="maxPoolSize">25</property>
        <!-- 数据库连接池中的最小的数据库连接数 -->
        <property name="minPoolSize">5</property>
    </named-config>
</c3p0-config>

数据库连接：

package com.web.jdbc;

import com.mchange.v2.c3p0.ComboPooledDataSource;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

/**
 * 创建时间 2021/11/25
 * 描述：jdbc
 * @author 鄢富友
 */
public class BaseDao {
    private static PreparedStatement ps;
    private static ResultSet rs;
    private static ComboPooledDataSource dspool;
    static Connection conn = null;
    static {
        dspool = new ComboPooledDataSource("test");
    }
    public Connection getConn(){
        try{
            conn = dspool.getConnection();
        }catch (Exception e){
            e.printStackTrace();
        }
        return conn;
    }

    public void closeAll(ResultSet rs,PreparedStatement ps,Connection conn){
            if (rs != null){
                try {
                    rs.close();
                }catch (Exception e){
                    e.printStackTrace();
                }
            }else if (ps != null){
                try {
                    ps.close();
                }catch (Exception e){
                    e.printStackTrace();
                }
            }else{
                if (conn != null){
                    try {
                        conn.close();
                    }catch (Exception e){
                        e.printStackTrace();
                    }
                }
            }
    }
}

数据库交互的接口：

package com.web.dao;

import com.web.beans.FileTest;

import java.util.List;

public interface FileService {
    int addFile(FileTest file_bean);
    List<FileTest> fileList();
    String getfilepath(String id);
}

接口实现：

package com.web.dao.impl;

import com.web.beans.FileTest;
import com.web.dao.FileService;
import com.web.jdbc.BaseDao;

import java.io.File;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

/**
 * 创建时间 2021/11/25
 * 描述：
 */
public class FileServiceImpl implements FileService {
    static BaseDao dao = new BaseDao();
    private static PreparedStatement ps;
    private static ResultSet rs;
    static Connection conn = null;
    @Override
    public int addFile(FileTest file_bean) {
        int i = 0;
        String sql ="insert into file(filename,filepath) values(?,?);";
        try {
            conn = dao.getConn();
            ps = conn.prepareStatement(sql);
            ps.setObject(1,file_bean.getFilename());
            ps.setObject(2,file_bean.getFilepath());
            i = ps.executeUpdate();
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            dao.closeAll(rs,ps,conn);
        }
        return i;
    }

    @Override
    public List<FileTest> fileList() {
        String sql = "select * from file;";
        List<FileTest> file_list = new ArrayList<>();
        try{
            conn = dao.getConn();
            ps = conn.prepareStatement(sql);
            rs = ps.executeQuery();
            while (rs.next()){
                FileTest oneFile = new FileTest(Integer.parseInt(rs.getString("id")),rs.getString("filename"),rs.getString("filepath"));
                file_list.add(oneFile);
            }
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            dao.closeAll(rs,ps,conn);
        }
        return file_list;
    }

    @Override
    public String getfilepath(String id) {
        String filepath = null;
        String sql = "select filepath from file where id=?;";
        try{
            conn = dao.getConn();
            ps = conn.prepareStatement(sql);
            ps.setObject(1,id);
            rs = ps.executeQuery();
            while (rs.next()){
                filepath = rs.getString("filepath");
            }
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            dao.closeAll(rs,ps,conn);
        }
        return filepath;
    }
}

文件上传的servlet：

package com.web.Servlet;

import com.web.beans.FileTest;
import com.web.dao.impl.FileServiceImpl;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.util.List;

/**
 * 创建时间 2021/11/25
 * 描述：上传
 * @author 鄢富友
 */
@WebServlet("/upfile")
public class UpServlet extends HttpServlet {
    private static FileServiceImpl fileService = new FileServiceImpl();
    protected void doGet(HttpServletRequest req, HttpServletResponse res){
        String savePath = this.getServletContext().getRealPath("/WEB-INF/upload/");
        File path = new File(savePath);
//        获取时间戳防止文件覆盖
        Long startTs = System.currentTimeMillis();
        if (!path.exists() && !path.isDirectory()){
            path.mkdirs();
        }
        try {
            DiskFileItemFactory factory = new DiskFileItemFactory();
            ServletFileUpload up = new ServletFileUpload(factory);
            up.setHeaderEncoding("UTF-8");
            if (!ServletFileUpload.isMultipartContent(req)){
                return;
            }
            List<FileItem> file_list = up.parseRequest(req);
            FileTest test_file = new FileTest();
            int file_num = 0;
            for (FileItem onefile : file_list){
                if (!onefile.isFormField()){
                    String filename = onefile.getName();
                    if (filename == null || filename.trim().equals("")){
                        System.out.println("未选择文件！");
                        continue;
                    }
                    System.out.println(savePath+filename);
                    file_num ++;
                    test_file.setFilename(filename);
                    test_file.setFilepath(savePath+filename);
                    String filepath = savePath+filename;
                    InputStream in = onefile.getInputStream();
                    OutputStream out = new FileOutputStream(filepath);
                    byte[] bytes = new byte[1024];
                    int len = 0;
                    while ((len = in.read(bytes)) != -1){
                        out.write(bytes,0,len);
                    }
                    in.close();
                    out.close();
                    onefile.delete();
                    System.out.println(test_file);
                    fileService.addFile(test_file);
                }
            }
            req.setAttribute("msg","上传成功！" + file_num + "个");
            req.getRequestDispatcher("/index.jsp").forward(req,res);
            return;
        }catch (Exception e){
            e.printStackTrace();
        }
    }
    protected void doPost(HttpServletRequest req,HttpServletResponse res){
        doGet(req, res);
    }
}

文件列表的servlet：

package com.web.Servlet;

import com.web.beans.FileTest;
import com.web.dao.impl.FileServiceImpl;

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.IOException;
import java.util.List;

/**
 * 创建时间 2021/11/26
 * 描述：文件列表
 * @author 鄢富友
 */
@WebServlet("/filelist")
public class FileListServlet extends HttpServlet {
    public void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
        FileServiceImpl fileService = new FileServiceImpl();
        List<FileTest> fileList = fileService.fileList();
        req.setAttribute("filelist",fileList);
        req.getRequestDispatcher("/filelist.jsp").forward(req,res);
        return;
    }
    public void doPost(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
        doGet(req, res);
    }
}

文件下载的servlet：

package com.web.Servlet;

import com.web.dao.impl.FileServiceImpl;

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.io.FileInputStream;
import java.io.OutputStream;
import java.net.URLEncoder;

/**
 * 创建时间 2021/11/25
 * 描述：下载
 * @author 鄢富友
 */
@WebServlet("/downfile")
public class DownServlet extends HttpServlet {
    public void doGet(HttpServletRequest req, HttpServletResponse res){
//        文件路径
        String filename = req.getParameter("filename");
        String id = req.getParameter("id");
        FileServiceImpl fileService = new FileServiceImpl();
        String filepath = fileService.getfilepath(id);
        System.out.println(filename+"  "+filepath);
        res.setContentType("text/html;charset=UTF-8");
        try {
            if (filepath == null){
                req.setAttribute("msg","参数错误！");
                req.getRequestDispatcher("/filelist.jsp").forward(req,res);
                return;
            }
            File file = new File(filepath);
            if (!file.exists()){
                req.setAttribute("msg","文件不存在！");
                req.getRequestDispatcher("/filelist.jsp").forward(req,res);
                return;
            }
            res.addHeader("Content-Disposition","attachment;filename="+ URLEncoder.encode(filename,"UTF-8"));
            res.setContentType("multipart/form-data");
            FileInputStream in = new FileInputStream(filepath);
            OutputStream out = res.getOutputStream();
            byte buffer[] = new byte[1024];
            int len = 0;
            while ((len = in.read()) != -1){
                out.write(buffer,0,len);
            }
            in.close();
            out.close();
        }catch (Exception e){
            e.printStackTrace();
        }

    }
    public void doPost(HttpServletRequest req, HttpServletResponse res){
        doGet(req,res);
    }
}

今日份收工。