java实现文件在线预览

最新推荐文章于 2025-04-17 11:38:58 发布

weixin_39522272

最新推荐文章于 2025-04-17 11:38:58 发布

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文章标签： java

本文链接：https://blog.youkuaiyun.com/weixin_39522272/article/details/124192636

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本文档详细介绍了如何通过Java Servlet实现Thymeleaf3.0文档的三种不同方式预览和下载，包括设置Content-Type、读取文件内容并发送到HTTP响应。重点在于处理文件路径、输出流和HTTP头信息。

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@RequestMapping("/preview1")
public void er(HttpServletResponse response){
    File file = new File("G:\\桌面\\Thymeleaf3.0中文翻译文档@www.java1234.com.pdf");
    if (file.exists()){
        byte[] data = null;
        try {
            FileInputStream input = new FileInputStream(file);
            data = new byte[input.available()];
            input.read(data);
            response.getOutputStream().write(data);
            input.close();
        } catch (Exception e) {
            System.out.println(e);
        }
    }else{
        return;
    }
}
@ResponseBody
@RequestMapping("/preview2")
public void findPdf( HttpServletResponse response) throws IOException{
    response.setContentType("application/pdf");
    FileInputStream in = new FileInputStream(new File("G:\\桌面\\Thymeleaf3.0中文翻译文档@www.java1234.com.pdf"));
    OutputStream out = response.getOutputStream();
    byte[] b = new byte[512];
    while ((in.read(b))!=-1) {
        out.write(b);
    }
    out.flush();
    in.close();
    out.close();
}
@ResponseBody
@RequestMapping("/preview3")
public void devDoc(HttpServletRequest request, HttpServletResponse response, String storeName) throws Exception {
    request.setCharacterEncoding("UTF-8");
    String ctxPath = request.getSession().getServletContext().getRealPath("");
    String downLoadPath = "G:\\桌面\\Thymeleaf3.0中文翻译文档@www.java1234.com.pdf";
    response.setContentType("application/pdf");
    FileInputStream in = new FileInputStream(new File(downLoadPath));
    OutputStream out = response.getOutputStream();
    byte[] b = new byte[1024];
    while ((in.read(b))!=-1) {
        out.write(b);
    }
    out.flush();
    in.close();
    out.close();
}
@ResponseBody
@RequestMapping("/preview")
public void download( HttpServletResponse response
                    ) throws IOException {
    String filePath = "G:\\桌面\\Thymeleaf3.0中文翻译文档@www.java1234.com.pdf";
    System.out.println("filePath:" + filePath);
    File f = new File(filePath);
    if (!f.exists()) {
        response.sendError(404, "File not found!");
        return;
    }
    BufferedInputStream br = new BufferedInputStream(new FileInputStream(f));
    byte[] bs = new byte[1024];
    int len = 0;
    response.reset(); // 非常重要
    if (true) { // 在线打开方式
        URL u = new URL("file:///" + filePath);
        String contentType = u.openConnection().getContentType();
        response.setContentType(contentType);
        response.setHeader("Content-Disposition", "inline;filename="
                + "2019年上半年英语四级笔试准考证(戴林峰).pdf");
        // 文件名应该编码成utf-8，注意：使用时，我们可忽略这句
    } else {
        // 纯下载方式
        response.setContentType("application/x-msdownload");
        response.setHeader("Content-Disposition", "attachment;filename="
                + "2019年上半年英语四级笔试准考证(戴林峰).pdf");
    }
    OutputStream out = response.getOutputStream();
    while ((len = br.read(bs)) > 0) {
        out.write(bs, 0, len);
    }
    out.flush();
    out.close();
    br.close();
}