文件，图片上传

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最近看到了以前写的一个代码，使用ServletFileUpload上传文件或者图片，然后想想，代码都快丢了，就留个博客记录下吧！

前端index.jsp

<%@ page language="java" contentType="text/html; charset=utf-8"    pageEncoding="utf-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><title>文件上传</title></head><body><form action="LunboAction" method="post" enctype="multipart/form-data">本地目录：<input type="file" name="uploadFile" ><input type="submit" value="上传头像"></form></body></html>

Servlet类：LunboAction中的方法

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {HttpSession session = request.getSession();// 判断上传表单是否为multipart/form-data类型 if(ServletFileUpload.isMultipartContent(request)) {try { // 1. 创建DiskFileItemFactory对象（文件处理工厂），设置缓冲区大小和临时文件目录DiskFileItemFactory factory = new DiskFileItemFactory();System.out.println("默认的临时文件夹："+System.getProperty("java.io.tmpdir"));// 2. 创建ServletFileUpload对象（文件上传处理器），并设置上传文件的大小限制。  ServletFileUpload sfu = new ServletFileUpload(factory);sfu.setSizeMax(10*1024*1024);//10Msfu.setHeaderEncoding("utf-8");// 3 调用ServletFileUpload.parseRequest方法解析request对象，得到一个保存了所有上传内容的List对象。  List<FileItem> fileItemList = (List<FileItem>)sfu.parseRequest(new ServletRequestContext(request));        Iterator<FileItem> fileItems = fileItemList.iterator();         // 4. 遍历list，每迭代一个FileItem对象，调用其isFormField方法判断是否是上传文件          while(fileItems.hasNext()) {     FileItem fileItem = fileItems.next();     if(fileItem.isFormField()) {     String name = fileItem.getFieldName();     String value = fileItem.getString("utf-8");     System.out.println(name+"="+value);     } else {     //信息的文件格式     String fileName = fileItem.getName();     System.out.println("原文件名："+fileName);     String suffix = fileName.substring(fileName.lastIndexOf('.'));     System.out.println("扩展名："+suffix);          //新文件名     String newFileName = new Date().getTime()+suffix;     System.out.println("新文件名："+newFileName);          //5调用fileItem的write方法，写入文件     File file = new File("D:/mywork/20170814ImageUpload/WebContent/touxiang/"+newFileName);     System.out.println(file.getAbsolutePath());     fileItem.write(file);          //6,调用fileItem的delete方法删除临时文件     fileItem.delete();     //7 存到数据库，保存源文件名称2，保存相对路径     try {Class.forName("com.mysql.jdbc.Driver");String url = "jdbc:mysql://localhost:3306/test";String name = "root";String password = "root";Connection conn = DriverManager.getConnection(url, name, password);String Sql = "INSERT INTO t_touxiang(image_path,user_id,old_name)VALUES(?,?,?)";PreparedStatement ps = conn.prepareStatement(Sql);ps.setString(1, newFileName);ps.setInt(2, 1111);ps.setString(3, fileName);int rows = ps.executeUpdate();if(rows > 0) {session.setAttribute("image_name", fileName);session.setAttribute("image_path","touxiang/"+newFileName);response.sendRedirect(request.getContextPath()+"/readPicture");} else {response.sendRedirect("http://www.baidu.com");}} catch (Exception e) {}     }     }} catch (Exception e) {}}}

然后后台的Servlet读取图片信息

protected void service(HttpServletRequest request, HttpServletResponse response)          throws ServletException, IOException {  String result = null;try {int id =2;String sqlString="SELECT image_path FROM t_touxiang WHERE id=?";Class.forName("com.mysql.jdbc.Driver");String url = "jdbc:mysql://localhost:3306/test";String name = "root";String password = "root";Connection conn = DriverManager.getConnection(url, name, password);PreparedStatement ps = conn.prepareStatement(sqlString);ps.setInt(1, id);ResultSet urs = ps.executeQuery();while(urs.next()) {System.out.println(urs.getString("image_path"));result = urs.getString("image_path");}} catch (Exception e) {System.out.println(e.getMessage());}request.setAttribute("txt", result);request.getRequestDispatcher("/ShowImage.jsp").forward(request, response);}

前台展示图片，ShowImage.jsp

<%@ page language="java" contentType="text/html; charset=utf-8"    pageEncoding="utf-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><title>Insert title here</title><%String path = (String)request.getAttribute("txt");%></head><body>    <span style="white-space:pre"></span><div>          <form action="" method="post" enctype="multipart/form-data">                <img src="./touxiang/<%=path %>"  width="200" height="200">       </form>          </div>  </body></html>

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