Struts 6.3.0.2升级后PDF/Word文档下载损坏问题求助

升级后PDF和docx文件下载出现损坏：

• 下载的PDF无法打开
• docx文件打开时显示自定义提示「系统无法处理您的请求」
• 控制台日志显示文件已成功下载，但docx仍无法打开

升级前原有代码 #

import java.io.*;
import java.nio.file.Files;
import java.util.ResourceBundle;

public void downloadAttach(){
    try {
        String filename = DotsFormUtil.cleanStringFile(request.getParameter("filename"));
        String realname = DotsFormUtil.cleanStringFile(request.getParameter("name"));

        HttpSession session = (HttpSession) request.getSession();
        String strDotsIdToken = (String) session.getAttribute("strDotsIdToken");

        try{
            if(strDotsIdToken == null || !strDotsIdToken.equals(filename.split("_")[0]))
                logger.error("strDotsIdToken is null or strDotsIdToken is not equal and Exception is thrown");
        }catch (Exception e){
            logger.info(e);
        }
        try {
            if(filename!= null){
               ServletOutputStream out = null;
               FileInputStream fi = null;
                try {
                    ResourceBundle bundle = ResourceBundle.getBundle("resources.dotsDisplay");
                    String strDirectory=DotsFormUtil.cleanpString(bundle.getString("dots.attachments.path"));
                    File f= new File(FilenameUtils.normalize(DotsFormUtil.cleanString(strDirectory+File.separator + filename)));
                    String pattern = "[a-zA-Z0-9]{1,50}\\.[a-zA-Z0-9]{1,10}";
                    if(realname.matches(pattern)){

                        response.setHeader("Content-Disposition","attachment; fileName=" +realname);
                    }
                    response.addHeader("Content-Transfer-Encoding","base64");

                    out = response.getOutputStream();
                    fi= new FileInputStream(f);
                    byte[] buffer = new byte[(int)f.length()];

                    int readInt=fi.read(buffer);
                    try{
                        if(readInt != -1){
                            out.write(buffer);
                            out.flush();
                        }
                    }catch (Exception e){
                        logger.info(e);
                    }
                } catch (FileNotFoundException e){
                    e.printStackTrace();
                    logger.info("File not found error" + filename);
                    logger.error(e.getMessage());
                }catch (IOException e){
                    logger.info("error in reading file:" + filename);
                }finally {
                    if(out != null) safeClose(out);
                    if(fi != null) safeClose(fi);
                }
            }
        }catch (Exception e){
            e.printStackTrace();
            logger.error(e.getMessage(),e);
        }
        logger.info("successfully download attachment file");
    }catch (Exception e){
        e.printStackTrace();
    }
}

public static String cleanStringFile(String aString){
    if(aString==null) return null;
    String cleanString = "";
    char cleanChar = '\0';
    for(int i=0; i<aString.length(); i++){
        cleanChar = cleanCharFile(aString.charAt(i));
        if(cleanChar != '\0') cleanString+=cleanChar;
    }
    return cleanString;
}

private static char cleanCharFile(char aChar){
    for(int i = 48; i<58; ++i){
        if(aChar ==i) return (char) i;
    }
    for(int i = 65; i<91; ++i){
        if(aChar ==i) return (char) i;
    }
    for(int i = 97; i<123; ++i){
        if(aChar ==i) return (char) i;
    }

    switch (aChar){
        case '.':
            return '.';
        case '_':
            return '_';
        case '-':
            return '-';
        case '!':
            return '!';
    }
    return '\0';
}

调整后代码 #

import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.Path;

public class getDotsMissionAction {

    public void downloadAttach() {
        // Your existing code...

        try {
            if (filename != null) {
                try {
                    ResourceBundle bundle = ResourceBundle.getBundle("resources.dotsDisplay");
                    String strDirectory =  DotsFormUtil.cleanString(bundle.getString("dots.attachments.path"));
                    File f = new File(strDirectory + File.separator + filename);
                    String pattern = "[a-zA-Z0-9]{1,50}\\.[a-zA-Z0-9]{1,10}";
                    if (realname.matches(pattern)) {
                        response.reset();
                        response.setCharacterEncoding("UTF-8");
                        response.setContentType("application/pdf");
                        response.setContentType("application/vnd.openxmlformats-officedocument.wordprocessingml.document");
                        response.setHeader("Content-Disposition", "attachment; fileName=" + realname);

                        try (FileInputStream fis = new FileInputStream(f);
                             OutputStream out2 = response.getOutputStream()) {
                            byte[] buffer = new byte[1024];
                            int bytesRead;
                            while ((bytesRead = fis.read(buffer)) != -1) {
                                out2.write(buffer, 0, bytesRead);
                            }
                        }
                    }
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                    logger.error(e.getMessage());
                }
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            logger.error(e.getMessage());
        }
        logger.info("successfully download attachment file");
    }
}

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import javax.servlet.http.HttpServletResponse;

public class getDotsMissionAction {

    public void downloadAttach(HttpServletResponse response) {
        // Your existing code...

        try {
            if (filename != null) {
                ResourceBundle bundle = ResourceBundle.getBundle("resources.dotsDisplay");
                String strDirectory = DotsFormUtil.cleanString(bundle.getString("dots.attachments.path"));
                File f = new File(strDirectory + File.separator + filename);
                String pattern = "[a-zA-Z0-9]{1,50}\\.[a-zA-Z0-9]{1,10}";
                if (realname.matches(pattern)) {
                    response.reset();
                    response.setCharacterEncoding("UTF-8");

                    // Determine content type based on file extension
                    String contentType;
                    if (realname.toLowerCase().endsWith(".pdf")) {
                        contentType = "application/pdf";
                    } else if (realname.toLowerCase().endsWith(".docx")) {
                        contentType = "application/vnd.openxmlformats-officedocument.wordprocessingml.document";
                    } else {
                        // Add more content types as needed
                        contentType = "application/octet-stream"; // Default to binary
                    }
                    response.setContentType(contentType);
                    response.setHeader("Content-Disposition", "attachment; filename=" + realname);

                    try (FileInputStream fis = new FileInputStream(f);
                         OutputStream out2 = response.getOutputStream()) {
                        byte[] buffer = new byte[1024];
                        int bytesRead;
                        while ((bytesRead = fis.read(buffer)) != -1) {
                            out2.write(buffer, 0, bytesRead);
                        }
                    }
                } else {
                    // Handle invalid filename pattern
                    // For example: Log an error, return a response indicating invalid file, etc.
                }
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            logger.error(e.getMessage());
        } catch (IOException e) {
            e.printStackTrace();
            logger.error(e.getMessage());
        }
        logger.info("successfully download attachment file");
    }

    // Your other methods...
}

解决方案 #

• 移除二进制文件的字符编码设置：删除response.setCharacterEncoding("UTF-8")，二进制文件不需要字符编码，该设置会破坏文件流结构。
• 修复文件名编码：Struts 6.x对响应头解析更严格，文件名需采用UTF-8编码的标准格式：

  import java.net.URLEncoder;
  // ...
  String encodedFilename = URLEncoder.encode(realname, "UTF-8");
  response.setHeader("Content-Disposition", "attachment; filename*=UTF-8''" + encodedFilename);
  

• 添加Content-Length头：明确告诉浏览器文件大小，避免接收不完整：

  response.setContentLengthLong(f.length());
  

• 清理响应状态：确保response.reset()在所有响应头设置前调用，清除可能残留的响应数据。
• 移除错误的Content-Transfer-Encoding头：升级前代码中添加的base64编码头会导致二进制文件被错误编码，必须删除。
• 使用Struts官方推荐的@Stream注解：简化文件下载逻辑，避免手动处理流的常见错误：

  import org.apache.struts2.convention.annotation.Action;
  import org.apache.struts2.convention.annotation.Result;
  import org.apache.struts2.stream.annotations.Stream;
  import java.io.FileInputStream;
  import java.io.InputStream;
  
  @Action(value = "downloadAttach", results = @Result(type = "stream"))
  public class getDotsMissionAction {
      private String realname;
      private File f;
  
      @Stream(value = "attachment", 
              contentType = "${contentType}", 
              contentLength = "${fileSize}", 
              fileName = "${encodedFilename}")
      public InputStream getAttachmentStream() throws Exception {
          return new FileInputStream(f);
      }
  
      // 初始化file、realname等参数的逻辑
      public String execute() throws Exception {
          // 原有验证、文件路径获取逻辑
          return "success";
      }
  
      // getter方法供@Stream注解使用
      public String getContentType() {
          if (realname.toLowerCase().endsWith(".pdf")) {
              return "application/pdf";
          } else if (realname.toLowerCase().endsWith(".docx")) {
              return "application/vnd.openxmlformats-officedocument.wordprocessingml.document";
          }
          return "application/octet-stream";
      }
  
      public long getFileSize() {
          return f.length();
      }
  
      public String getEncodedFilename() throws Exception {
          return URLEncoder.encode(realname, "UTF-8");
      }
  
      // 其他getter/setter
  }
  

• 检查拦截器干扰：在struts.xml中为该action排除可能修改响应流的拦截器，比如encoding拦截器：

  <action name="downloadAttach" class="com.yourpackage.getDotsMissionAction">
      <interceptor-ref name="defaultStack">
          <param name="encoding.excludeMethods">downloadAttach</param>
      </interceptor-ref>
      <result type="stream">
          <param name="contentType">${contentType}</param>
          <param name="contentDisposition">attachment; filename*=UTF-8''${encodedFilename}</param>
          <param name="contentLength">${fileSize}</param>
          <param name="inputName">attachmentStream</param>
      </result>
  </action>
  

内容的提问来源于stack exchange，提问作者Mahabir Gupta