文件（图片）资源上传到Javaweb项目中

ゝ一纸荒年。 2022-06-14 20:45 211阅读 0赞

上传的原理：
    ①获取本地的文件或图片资源(电脑中真实存在的资源)
    ②使用form表单将图片上传到servlet
    ③servlet复制到你设置的路径中(一般都复制到你的项目中)
    ④然后再把图片地址存储到数据库中
    具体步骤
    ①下载commons-fileupload-1.3.1.jar或者其他的fileupload的jar包
    ②给form表单添加 enctype="multipart/form-data" method="post"
    这两个属性必<form id="addForm" action="/addNewTrack.express" enctype="multipart/form-data" method="post">
                <table class="panelTable" border="0" cellspacing="0" cellpadding="0">
                    <tbody>
                    <tr>
                        <td>站点编号：</td>
                        <td><input name="station_id" type="text" readonly="readonly" required="required" /></td>
                        <td>快递单日期：</td>
                        <td><input name="track_date" type="text" readonly="readonly" required="required" /></td>
                    </tr>
                    <tr>
                        <td>寄件人姓名：</td>
                        <td><input name="client_name" type="text" required="required" /></td>
                        <td>寄件人电话：</td>
                        <td><input name="client_phone" type="text" required="required" /></td>
                    </tr>
                    <tr>
                        <td>寄件人邮件：</td>
                        <td colspan="3"><input name="client_email" type="text" required="required" /></td>
                    </tr>
                    <tr>
                        <td>寄件人地址：</td>
                        <td colspan="3">
                            <input name="clientAddressCountry" type="text" placeholder="国家" />
                            <input name="clientAddressProvince" type="text" placeholder="省份" required="required" />
                            <input name="clientAddressCity" type="text" placeholder="城市/直辖市" required="required" />
                            <input name="clientAddressCounty" type="text" placeholder="县/区" required="required" />
                            <input name="clientAddressTown" type="text" placeholder="镇/街道" required="required" />
                            <input name="clientAddressVillage" type="text" placeholder="村" />
                        </td>
                    </tr>
                    <tr>
                        <td>收件人姓名：</td>
                        <td><input name="recipients_name" type="text" required="required" /></td>
                        <td>收件人电话：</td>
                        <td><input name="recipients_phone" type="text" required="required" /></td>
                    </tr>
                    <tr>
                        <td>收件人邮件：</td>
                        <td colspan="3"><input name="recipients_email" type="text" required="required" /></td>
                    </tr>
                    <tr>
                        <td>收件人地址：</td>
                        <td colspan="3">
                            <input name="recipientsAddressCountry" type="text" placeholder="国家" />
                            <input name="recipientsAddressProvince" type="text" placeholder="省份" required="required" />
                            <input name="recipientsAddressCity" type="text" placeholder="城市/直辖市" required="required" />
                            <input name="recipientsAddressCounty" type="text" placeholder="县/区" required="required" />
                            <input name="recipientsAddressTown" type="text" placeholder="镇/街道" required="required" />
                            <input name="recipientsAddressVillage" type="text" placeholder="村" />
                        </td>
                    </tr>
                    <tr>
                        <td>包裹名称：</td>
                        <td><input name="package_content" type="text" /></td>
                        <td>包裹重量：</td>
                        <td><input name="package_weight" type="text" required="required" /></td>
                    </tr>
                    <tr>
                        <td>包裹是否保价：</td>
                        <td>
                            <select name="package_supportValue">
                                <option value="否">否</option>
                                <option value="是">是</option>
                            </select>
                        </td>
                        <td>包裹价值评估：</td>
                        <td>
                            <select name="package_valueDeclare">
                                <option value="不评估">不评估</option>
                                <option value="100-300">100-300</option>
                                <option value="300-500">300-500</option>
                                <option value="其他">其他</option>
                            </select>
                        </td>
                    </tr>
                    <tr>
                        <td>包裹运费：</td>
                        <td><input name="package_freight" type="text" required="required" /></td>
                        <td colspan="2">
                            <a href="http://www.sf-express.com/cn/sc/dynamic_functions/price/" target="_blank"><input type="button" value="计算运费" /></a>
                        </td>
                    </tr>
                    <tr>
                        <td>包裹备注：</td>
                    </tr>
                    <tr>
                        <td colspan="4">
                            <textarea name="package_remark" rows="5"></textarea>
                        </td>
                    </tr>
                    <tr>
                        <td>包裹图片：</td>
                        <td><input id="add_file_upload" name="upload" type="file" value="上传图片" accept="image/*" required="required" /></td>
                        <td style="display: none"><input type="submit" value="提交文件" /></td>
                    </tr>
                    </tbody>
                </table>
                <div class="image_container" style="padding: 0 20px;">
                    <img id="add_preview" style="height:170px;width: auto;border-width:0px;"/>
                </div>
            </form>
    ③将form表单根据web.xml的设置提交到对应servlet中
    
    
        <servlet>
            <servlet-name>express</servlet-name>
            <servlet-class>com.wzb.servlet.ExpressServlet</servlet-class>
        </servlet>
        <servlet-mapping>
            <servlet-name>express</servlet-name>
            <url-pattern>*.express</url-pattern>
        </servlet-mapping>

这里有一个需要注意的地方：  
如果你想使用ajax提交其他普通数据，form表单只提交上传文件，并且使用js提交，那么你会发现不管表单是否首先提交，它都比ajax提交的慢，换句话说，先执行ajax的一系列操作，然后执行form表单操作。这会给你的代码造成倍的困难，而且本来只需一次向数据库插入操作，由于两次提交，至少要进行两次操做，所以结论是：你最好都是用form表单提交的形式，之后servlet中加上  
response.sendRedirect(request.getContextPath()+”/page/proscenium/ticketMsgManage.jsp”);  
别忘了返回当前页面  
④servlet对上传文件进行业务处理  
@Override  
public void insertData(HttpServletRequest request, HttpServletResponse response) throws Exception \{  
/\*\*  
\* 首先判断form的enctype是不是multipart/form-data  
\* 同时也判断了form的提交方式是不是post  
\* 方法：isMultipartContent(request)  
\*/  
//将ajax传入的参数作为属性值传入到LoginEmployeeModel实例  
//创建一个TrackTicketModel实例  
TrackTicketModel trackTicketModel = new TrackTicketModel();  
String package\_img = null;  
//保存普通表单域的参数  
//获取ajax传入的值  
//设置日期转化格式  
SimpleDateFormat format = new SimpleDateFormat(“yyyy-MM-dd HH:mm:ss”);  
Date track\_date = null;  
String client\_name = null;  
String client\_phone = null;  
String client\_email = null;  
String clientAddressCountry = null;  
String clientAddressProvince = null;  
String clientAddressCity = null;  
String clientAddressCounty = null;  
String clientAddressTown = null;  
String clientAddressVillage = null;  
String recipients\_name = null;  
String recipients\_phone = null;  
String recipients\_email = null;  
String recipientsAddressCountry = null;  
String recipientsAddressProvince = null;  
String recipientsAddressCity = null;  
String recipientsAddressCounty = null;  
String recipientsAddressTown = null;  
String recipientsAddressVillage = null;  
String package\_content = null;  
BigDecimal package\_weight = null;  
String package\_supportValue = null;  
String package\_valueDeclare = null;  
BigDecimal package\_freight = null;  
String package\_remark = null;  
if(ServletFileUpload.isMultipartContent(request))\{  
request.setCharacterEncoding(“utf-8”);

// 实例化一个硬盘文件工厂,用来配置上传组件ServletFileUpload
            DiskFileItemFactory factory =  new DiskFileItemFactory();
    
            //设置文件存放的临时文件夹，这个文件夹要真实存在
            File fileDir = new File("H:\\image");
            if(fileDir.isDirectory() && fileDir.exists()==false){
                fileDir.mkdir();
            }
            factory.setRepository(fileDir);
    
            //设置最大占用的内存
            factory.setSizeThreshold(1024000);
    
            //创建ServletFileUpload对象
            ServletFileUpload sfu = new ServletFileUpload(factory);
            sfu.setHeaderEncoding("utf-8");
    
            //设置单个文件最大值byte
            sfu.setFileSizeMax(102400000);
    
            //所有上传文件的总和最大值byte
            sfu.setSizeMax(204800000);
    
            List<FileItem> items =  null;
    
            try {
                items = sfu.parseRequest(request);
            }catch (FileUploadBase.SizeLimitExceededException e) {
                System.out.println("文件大小超过了最大值");
            } catch(FileUploadException e) {
                e.printStackTrace();
            }
    
            //取得items的迭代器
            Iterator<FileItem> iter = items==null?null:items.iterator();
    
            //图片上传后存放的路径目录
            File images = new File("E:/IDEA_workatation/ECMBS/web/assert/upload/images");
            if(images.exists()==false){
                images.mkdirs();
            }
    
            //迭代items
            while(iter!=null && iter.hasNext()){
                FileItem item = (FileItem) iter.next();
                //如果传过来的是普通的表单域
                if(item.isFormField()){
                    if ("track_date".equals(item.getFieldName())){
                        track_date = format.parse(item.getString("UTF-8"));
                    }
                    if ("client_name".equals(item.getFieldName())){
                        client_name = item.getString("UTF-8");
                    }
                    if ("client_phone".equals(item.getFieldName())){
                        client_phone = item.getString("UTF-8");
                    }
                    if ("client_email".equals(item.getFieldName())){
                        client_email = item.getString("UTF-8");
                    }
                    if ("clientAddressCountry".equals(item.getFieldName())){
                        clientAddressCountry = item.getString("UTF-8");
                    }
                    if ("clientAddressProvince".equals(item.getFieldName())){
                        clientAddressProvince = item.getString("UTF-8");
                    }
                    if ("clientAddressCity".equals(item.getFieldName())){
                        clientAddressCity = item.getString("UTF-8");
                    }
                    if ("clientAddressCounty".equals(item.getFieldName())){
                        clientAddressCounty = item.getString("UTF-8");
                    }
                    if ("clientAddressTown".equals(item.getFieldName())){
                        clientAddressTown = item.getString("UTF-8");
                    }
                    if ("clientAddressVillage".equals(item.getFieldName())){
                        clientAddressVillage = item.getString("UTF-8");
                    }
                    if ("recipients_name".equals(item.getFieldName())){
                        recipients_name = item.getString("UTF-8");
                    }
                    if ("recipients_phone".equals(item.getFieldName())){
                        recipients_phone = item.getString("UTF-8");
                    }
                    if ("recipients_email".equals(item.getFieldName())){
                        recipients_email = item.getString("UTF-8");
                    }
                    if ("recipientsAddressCountry".equals(item.getFieldName())){
                        recipientsAddressCountry = item.getString("UTF-8");
                    }
                    if ("recipientsAddressProvince".equals(item.getFieldName())){
                        recipientsAddressProvince = item.getString("UTF-8");
                    }
                    if ("recipientsAddressCity".equals(item.getFieldName())){
                        recipientsAddressCity = item.getString("UTF-8");
                    }
                    if ("recipientsAddressCounty".equals(item.getFieldName())){
                        recipientsAddressCounty = item.getString("UTF-8");
                    }
                    if ("recipientsAddressTown".equals(item.getFieldName())){
                        recipientsAddressTown = item.getString("UTF-8");
                    }
                    if ("recipientsAddressVillage".equals(item.getFieldName())){
                        recipientsAddressVillage = item.getString("UTF-8");
                    }
                    if ("package_content".equals(item.getFieldName())){
                        package_content = item.getString("UTF-8");
                    }
                    if ("package_weight".equals(item.getFieldName())){
                        package_weight = BigDecimal.valueOf(Double.valueOf(item.getString("UTF-8")));
                    }
                    if ("package_supportValue".equals(item.getFieldName())){
                        package_supportValue = item.getString("UTF-8");
                    }
                    if ("package_valueDeclare".equals(item.getFieldName())){
                        package_valueDeclare = item.getString("UTF-8");
                    }
                    if ("package_freight".equals(item.getFieldName())){
                        package_freight = BigDecimal.valueOf(Double.valueOf(item.getString("UTF-8")));
                    }
                    if ("package_remark".equals(item.getFieldName())){
                        package_remark = item.getString("UTF-8");
                    }
                }
                //文件域
                else if(!item.isFormField()){
                    //System.out.println("源图片:" + item.getName());
                    String fileName = item.getName();
                    BufferedInputStream in = new BufferedInputStream(item.getInputStream());
                    //文件存储在H:/upload/images/目录下,这个目录也得存在
                    BufferedOutputStream out = new BufferedOutputStream(
                            new FileOutputStream(new File(images.getAbsolutePath()+"/"+fileName)));
                    Streams.copy(in, out, true);
                    //使用Session保存图片路径
                    String url = request.getContextPath()+"/assert/upload/images/"+fileName;
                    package_img = url;
                    trackTicketModel.setPackage_img(package_img);
                    System.out.println("url : "+url);
                }
            }
        }else {
            System.out.println("表单的enctype 类型错误");
        }
        //设置属性值
        trackTicketModel.setTrack_date(track_date);
        trackTicketModel.setClient_name(client_name);
        trackTicketModel.setClient_phone(client_phone);
        trackTicketModel.setClient_email(client_email);
        trackTicketModel.setClientAddressCountry(clientAddressCountry);
        trackTicketModel.setClientAddressProvince(clientAddressProvince);
        trackTicketModel.setClientAddressCity(clientAddressCity);
        trackTicketModel.setClientAddressCounty(clientAddressCounty);
        trackTicketModel.setClientAddressTown(clientAddressTown);
        trackTicketModel.setClientAddressVillage(clientAddressVillage);
        trackTicketModel.setRecipients_name(recipients_name);
        trackTicketModel.setRecipients_phone(recipients_phone);
        trackTicketModel.setRecipients_email(recipients_email);
        trackTicketModel.setRecipientsAddressCountry(recipientsAddressCountry);
        trackTicketModel.setRecipientsAddressProvince(recipientsAddressProvince);
        trackTicketModel.setRecipientsAddressCity(recipientsAddressCity);
        trackTicketModel.setRecipientsAddressCounty(recipientsAddressCounty);
        trackTicketModel.setRecipientsAddressTown(recipientsAddressTown);
        trackTicketModel.setRecipientsAddressVillage(recipientsAddressVillage);
        trackTicketModel.setPackage_content(package_content);
        trackTicketModel.setPackage_freight(package_freight);
        trackTicketModel.setPackage_weight(package_weight);
        trackTicketModel.setPackage_remark(package_remark);
        trackTicketModel.setPackage_supportValue(package_supportValue);
        trackTicketModel.setPackage_valueDeclare(package_valueDeclare);
        trackTicketModel.setEmployee_id(loginEmployee.getEmployee_id());
        trackTicketModel.setStationAddressUniqueId(GetUUIDUtil.getId());
        trackTicketModel.setEmployeeAddressUniqueId(GetUUIDUtil.getId());
        trackTicketModel.setClientAddressUniqueId(GetUUIDUtil.getId());
        trackTicketModel.setRecipientsAddressUniqueId(GetUUIDUtil.getId());
        trackTicketModel.setClient_uiqueId(GetUUIDUtil.getId());
        trackTicketModel.setRecipients_uiqueId(GetUUIDUtil.getId());
        trackTicketModel.setPackage_uiqueId(GetUUIDUtil.getId());
        //创建LoginImpl实例
        ExpressImpl expressImpl = new ExpressImpl();
        expressImpl.trackTicketModel1 = trackTicketModel;
        //调用LoginImpl实例的方法向数据库插入新的登录用户
        int returnValue = expressImpl.insertTrack(new HashMap<String, Object>());
        //创建一个输出流对象
        PrintWriter out = response.getWriter();
        //定义一个判断插入是否成功的变量
        boolean flag = false;
        //如果returnValue等于1，表示插入成功，否则失败
        if(returnValue == 1){
            flag = true;
        }
        //向前台发送信息
        try {
            //out.print(String.valueOf(flag));
            response.sendRedirect(request.getContextPath()+"/page/proscenium/ticketMsgManage.jsp");
        }catch (Exception e){
            System.out.println("Error Location : "+"ExpressServlet"+"."+"insertData");
            System.out.println("Error Case : "+"新增快递单信息"+"失败");
            e.printStackTrace();
        }finally {
            //提交数据库操作和关闭数据库会话
            expressImpl.commitAndCloseSqlSession();
            //刷新输出流
            out.flush();
            //关闭输出流
            out.close();
        }
    }

⑤查看你的项目运行的结果，文件上传基本上好使了  
另外，你存储到数据库中的是文件或者图片的地址，而不是直接将图片或文件存储进去，这么做的原因是：  
首先对数据库的读/写的速度永远都赶不上文件系统处理的速度  
其次数据库备份变的巨大，越来越耗时间，最后对文件的访问需要穿越你的应用层和数据库层  
图片是数据库最大的杀手  
还是使用varchar存放一个url然后在调用吧！  
反正图片，文件，二进制数这三样东西永远别存数据库。