Question

我有一个名为export.jsp的网页，当用户访问domain / export.jsp时，我希望他通过servlet的doGet方法自动下载csv文件。之后我想显示实际的jsp文件，即export.jsp

我的doGet方法如下：

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //RequestDispatcher rd = request.getRequestDispatcher("/export.jsp");
        //rd.forward(request, response);

        //getting and loading the property file
        Properties propConfig = new Properties();
        Properties propLog = new Properties();

        Statement stmt = null;
        Connection connection = null;

        try {
            //Loading the property files
            propConfig.load(getServletContext().getResourceAsStream("/WEB-INF/config.properties"));
            propLog.load(getServletContext().getResourceAsStream("/WEB-INF/log4j.properties"));
            PropertyConfigurator.configure(propLog);

            logger.info("loaded log4j properties From Path: /WEB-INF/log4j.properties");

            connection = DbTools.getConnection(propConfig.getProperty("db_hostname"), 
                    propConfig.getProperty("db_port"), propConfig.getProperty("db_serviceName"),
                    propConfig.getProperty("db_userName"),propConfig.getProperty("db_password"));

            stmt = connection.createStatement();
            ResultSet rset = stmt .executeQuery("SELECT * FROM QACOMPLETE_DEFECT");

            File csvfile = FileTools.generateCsvFile(rset);


            response.setContentType("text/csv");
            response.setHeader("Content-Disposition", "inline; filename=\""+csvfile.getName()+"\"");

            OutputStream outputStream = response.getOutputStream();
            outputStream.write(Files.readAllBytes(Paths.get(csvfile.getAbsolutePath())));
            outputStream.flush();
            outputStream.close();

        } catch (SQLException e) {
            logger.error("SQLException", e);

        }catch (IOException e) {
            logger.error("IOexception, The user may have cancel the download ", e);
        }
        finally
        {
            DbTools.closeQuietly(stmt);
            DbTools.closeQuietly(connection);
        }
    }

我的web.xml如下：

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <servlet>
    <description></description>
    <display-name>DefectExporter</display-name>
    <servlet-name>DefectExporter</servlet-name>
    <servlet-class>exporter.DefectExporter</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>DefectExporter</servlet-name>
    <url-pattern>/export.jsp</url-pattern>
  </servlet-mapping>
</web-app>

我做错了吗？因为当我在浏览器中输入URL http://localhost:7001/DefectsExporter/export.jsp时，会触发doGet方法，但不会显示网页export.jsp。

Answer 1

你不能这样做，至少没有Javascript。

ServletResponse只能执行以下操作：返回csv数据或返回HTML页面。你绝对需要2个不同的请求（简单的普通请求或javascript一个）：首先下载一个csv文件，然后再显示JSP。

我能想象到满足这样一个要求的唯一方法就是servlet通过javascript和客户端发送页面，首先下载（并保存）csv文件，然后使用不同的URL发送JSP请求页。但是AFAIK，没办法做那个服务器端。

如何在显示jsp页面之前触发doGet

1 个答案: