java.io.FileNotFoundException : (No such file or directory) - Working with servlets 错误

Question

我正在使用 hibernate 和 tomcat。我所做的是创建一个具有文件输入的表单。在 servlet 中，我想将该文件转换为 byte[]。但是当我想创建 de File 时，没有目录:它只保存图像的名称，而不是路径。这是错误:

java.io.FileNotFoundException: oldi.png (No such file or directory) at java.io.FileInputStream.open(Native Method) at java.io.FileInputStream.(FileInputStream.java:138) at control.servlets.AddGenericItem.doPost(AddGenericItem.java:46) at javax.servlet.http.HttpServlet.service(HttpServlet.java:647) at javax.servlet.http.HttpServlet.service(HttpServlet.java:728) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:947) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1009) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at java.lang.Thread.run(Thread.java:724)

HTML:

<tr>
    <td>
        <font class="text_title">Image: </font>
    </td>
    <td>
        <input name="image" type="file">
    </td>
</tr>

<tr>
    <td>
        <input type="submit" value="submit" name="ctl00$MainContent$RegisterUserWizard$CreateUserStepContainer$CreateButton"
               id="ctl00_MainContent_RegisterUserWizard_CreateUserStepContainer_CreateButton"
               style="border-width:0px;">
    </td>
</tr>

小服务程序:

public class AddGenericItem extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse)
            throws ServletException, IOException {

//        HttpSession session = httpServletRequest.getSession();
        DatabaseManager databaseManager = new DatabaseManager();

        String name = httpServletRequest.getParameter("name");
        String description = httpServletRequest.getParameter("description");
        float price = Float.parseFloat(httpServletRequest.getParameter("price"));

        File image = new File(httpServletRequest.getParameter("image"));
        byte[] imageArray = new byte[(int) image.length()];
        try {
            FileInputStream fileInputStream = new FileInputStream(image);
            fileInputStream.read(imageArray);
            fileInputStream.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
        Admin admin = (Admin) httpServletRequest.getSession().getAttribute("user");
        Brand brand = admin.getBrand();

        GenericItem genericItem = new GenericItem(name, description, imageArray, price,brand);

        GenericItemDAO genericItemDAO = databaseManager.getGenericItemDAO();

        genericItemDAO.beginTransaction();
        genericItemDAO.save(genericItem);

        try {
            genericItemDAO.commitTransaction();
        } catch (DatabaseAccessFailException e) {
            e.getStackTrace();
        } finally {
            httpServletResponse.sendRedirect("/adminPages/items.jsp");
        }
    }

    @Override
    protected void doGet(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse)
            throws ServletException, IOException {

    }

    @Override
    protected void doDelete(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse)
            throws ServletException, IOException {

    }

}

Answer 1

希望您正在处理文件上传。

问题出在下面一行:

FileInputStream fileInputStream = new FileInputStream(image);

Servlet 在服务器上查找文件以读取它，但那时它不在那里。

---

使用Commons Fileupload library由 Apache 提供，可以轻松地向您的 servlet 和 Web 应用程序添加强大的、高性能的文件上传功能。

查找完整代码 here和 here和 here