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- 说明：基于jsp与servlet、mysql对的图片的上传与操作，servlet用于操作文件的上传。
- 实现上传需要包文件：commons-fileupload-1.3.2、commons-io-2.5.jar、mysql-connector-java5.1.26-bin.jar(数据库驱动，自行下载)
- 四个文件： 1.index.jsp(上传页面) 2..Upload.java(servlet 操作上传) 3.show_img.java(取图片) 4.show_img.jsp（显示图片）
- 数据库自己在mysql里面建好就行，图片的类型为blob(longblog、mediublob、tinyblob)
1.index.jsp
表单需要注意的地方：
- 表单的提交方式为：post
- 表单必须带上属性：enctype="multipart/form-data"
以下为主要代码：<body><div align="center"><form action="Upload.java" method="post" enctype="multipart/form-data"><table><tr><td>姓名：</td><td><input id="name" type="text" name="username"></td></tr><tr><td>选择上传的图片</td><td><input id="file1" type="file" name="Filename"></td></tr> <tr><td align="center" colspan="2"><input id="button"type="submit" value="上传"> <a id="a"href="show_img.jsp">查看上传图片</a></td></tr></table></form></div> </body> - 2.Upload.java（主要代码）
public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {response.setContentType("text/html;charset=gbk");request.setCharacterEncoding("gbk");response.setCharacterEncoding("gbk");PrintWriter out = response.getWriter();PreparedStatement pstmt;//获得PreparedStatment对象 ，PreparedStatment执行SQL查询语句的API,比 Statement 更快//加载数据库驱动Connection con;try {Class.forName("com.mysql.jdbc.Driver");} catch (ClassNotFoundException e2) {System.out.println("驱动找不到");}List Files = new ArrayList();//存取上传文件 String name = "";//存取上传人姓名 DiskFileItemFactory factory = new DiskFileItemFactory();//创建一个解析器工厂DiskFileItemFactory fu =new DiskFileItemFactory ();//得到解析器，处理上传的文件数据，并将表单中每个输入项封装成一个FileItem 对象中ServletFileUpload upload = new ServletFileUpload(fu);upload.setHeaderEncoding("gbk");try {//存取表单所有信息List<FileItem> list = upload.parseRequest(request);//取得表单的数据内容//此层增强for循环遍历表单中有多少个上传文件将文件存到list中for(FileItem items:list){if(items.isFormField()){//判断是否不是文件if(items.getFieldName().equals("username")){name=new String(items.getString().getBytes("ISO-8859-1"),"gbk");System.out.println(name);}System.out.println(items.getFieldName());}else{Files.add(items);}}//sql插入语句String sql ="insert into photo (username,p) values(?,?)";for(int i=0;i<Files.size();i++){FileItem item = (FileItem)Files.get(i);//从集合取出文件String filename = item.getName();//获得文件名InputStream file = item.getInputStream();//将文件转为输入流// read(byte[])方法,返回读入缓冲区的总字节数 byte[] buffer = new byte[file.available()];//将字节数组直接存进去数据库就可以file.read(buffer);try {con = (Connection) DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "9527");pstmt = con.prepareStatement(sql);//预处理pstmt.setString(1, name);//将第一个占位符（?）设值pstmt.setBytes(2, buffer);//将第二个占位符设值pstmt.executeUpdate();//执行语句file.close();//将流关闭System.out.println("插入图片成功");} catch (SQLException e1) {System.out.println(e1);}}} catch (FileUploadException e2) {e2.printStackTrace();}request.getRequestDispatcher("index.jsp").forward(request, response);} protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {response.setContentType("text/html;charset=gbk");request.setCharacterEncoding("gbk");response.setCharacterEncoding("gbk");PrintWriter out = response.getWriter();doGet(request, response);}
上传后的数据库：
3.show_img.java(取图片主要代码)
public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {response.setContentType("image/*");//设置为图pain方式request.setCharacterEncoding("gbk");response.setCharacterEncoding("gbk");Connection con;PreparedStatement pstmt;//获得PreparedStatement对象ResultSet rs=null;//通过img 的src 获得上传人String username =new String(request.getParameter("username").getBytes("ISO-8859-1"),"gbk");System.out.println(username);try {Class.forName("com.mysql.jdbc.Driver");} catch (ClassNotFoundException e2) {System.out.println("驱动找不到");}String sql="select * from photo where username =?";List img = new ArrayList();//存放img名字用于页面显示；try{con = (Connection) DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "9527");try{//实例化PreparedStatement对象pstmt = con.prepareStatement(sql);pstmt.setString(1, username);//查询条件根据上传人查询rs=pstmt.executeQuery();//执行查询if(rs.next()){//循环取出所有图片byte[] buff =rs.getBytes("p");//图片所在的字段名，前面存的是byte 现在相对应的取OutputStream os = response.getOutputStream();//获得输出流os.write(buff);//将其输出页面System.out.println("取出成功");}pstmt.close();rs.close();}catch(Exception e){System.out.println("取出失败 "+e);}} catch (SQLException e1) {System.out.println(e1);}} protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {response.setContentType("text/html;charset=gbk");request.setCharacterEncoding("gbk");response.setCharacterEncoding("gbk");PrintWriter out = response.getWriter();doGet(request, response);}<body><div align="center"><img width="400" alt="" src="show_img?username=张三">//取图片的查询条件</div>
</body>到此算是完成了，代码是灵活的 可根据实际情况进行修改与项目结合。如果您看了这文章有什么更好的建议，希望能得到您的指导，谢谢写！。如果对此不明白的可留言。
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