在Spring MVC中查看pdf文件中的文件内容（不可读）

Question

我已经完成了使用spring MultipartFile将文件上传到目标文件夹的操作。现在，我想单击查看按钮以pdf格式查看相同的文件。

这是我的jsp。

<form method="POST" action="fileSearch">

        <table id="abc1" cellpadding="9" bgcolor="74BAAC" width="50%"
            style="margin-top: 8px; margin-left: 320px;" cellspacing="9">
            <tr>

                <td>Name:</td>
                <td><input type="text" name="name"></td>
                <td>Category:</td>
                <td><select name="seldCategory" id="selectFileCategory">
                        <option value="selectFileCategory">selectFileCategory</option>
                        <option value="FileCategory1">FileCategory1</option>
                        <option value="FileCategory2">FileCategory2</option>
                        <option value="FileCategory3">FileCategory3</option>
                        <option value="FileCategory4">FileCategory4</option>
                </select></td>
                <td><input type="submit" value="search"></td>
            </tr>


        </table>
        <c:if test='${not empty "${fileSearchList}"}'>

            <table align="center" class="viewAllTripTable" border="1"
                style="display: center">
                <c:if test='${not empty "${fileSearchList}"}'>
                    <tr>
                        <td colspan="1"><b>Name:</b></td>
                        <td colspan="1"><b>Category:</b></td>
                        <td colspan="1"><b>View File</b></td>
                    </tr>
                </c:if>
                <c:forEach items="${fileSearchList}" var="fsList">
                    <tr>
                        <td><c:out value="${fsList.name}" /></td>
                        <td><c:out value="${fsList.category}" /></td>
                        <td><c:out value="${fsList.file_path}" /></td>

                        <td><a class="buy" href="view?file_path=${fsList.file_path}&file_name=${fsList.name}">view</a></td>
                    </tr>
                </c:forEach>

            </table>

        </c:if>
    </form>

我在这里传递两个参数文件Path和File Name，我认为下面的方法有很多更正。建议我以正确的方式进行操作。 我正在尝试在浏览器选项卡中查看特定文件。

            @RequestMapping(value = { "/view" }, method = RequestMethod.GET)
            public String viewFile(@RequestParam("file_path") String file_path,
                    @RequestParam("file_name") String fileName,
                    HttpServletResponse response, HttpServletRequest request)
                    throws IOException, DocumentException {

                String filePath = file_path.replace("/", "\\");
                System.out.println(filePath);
                FileInputStream is = null;
                BufferedReader bfReader = null;
                try {
                    File file = new File(filePath);
                    FileInputStream inputStream = new FileInputStream(file);
                    byte[] bytes = new byte[(int) file.length()];
                    inputStream.read(bytes);

                    FileOutputStream out = new FileOutputStream(file);
                    out.write(bytes);

                    Document d = new Document();
                    ByteArrayOutputStream baos = new ByteArrayOutputStream();
                    PdfWriter.getInstance(d, baos);
                    d.open();
                    d.add(new Paragraph("Hello World, iText"));
                    d.close();
                    response.setContentType("application/pdf");
                    response.setHeader("Content-disposition", "attachment; filename="
                            + fileName + ".pdf");
                    response.setHeader("Cache-Control",
                            "must-revalidate, post-check=0, pre-check=0");
                    response.setHeader("Expires", "0");
                    response.setHeader("Pragma", "No-cache");
                    response.setContentLength(baos.size());
                    ServletOutputStream outn = response.getOutputStream();
                    baos.writeTo(outn);
                    out.close();

                } catch (FileNotFoundException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                System.out.println("sasa" + filePath);
                return "searchPage";
            }

Answer 1

您可以尝试使用以下方式之一。

使用AbstractITextPdfView生成PDF并返回它。 需要一些配置。 您可以即兴显示此链接上显示的示例。

或者，您可以尝试以下操作：

更改方法签名以返回ResponseEntity<byte[]>并进行以下其他更改：

    @RequestMapping(value = { "/view" }, method = RequestMethod.GET)
    public ResponseEntity<byte[]> viewFile(@RequestParam("file_path") String file_path,
                @RequestParam("file_name") String fileName,
                HttpServletResponse response, HttpServletRequest request)
                throws IOException, DocumentException {

        byte[] fileContents = // retrieve the file contents

        HttpHeaders httpHeaders = new HttpHeaders();
        httpHeaders.setContentType(MediaType.parseMediaType("application/pdf"));
        String fileName= "yourReqdFileName.pdf";
        httpHeaders.setContentDispositionFormData(fileName, fileName);
        httpHeaders.setCacheControl("must-revalidate, post-check=0, pre-check=0");
        ResponseEntity<byte[]> serverResponse = new ResponseEntity<byte[]>(contents, headers, HttpStatus.OK);
        return serverResponse;
    }