文件工具类，一些常用的文件方法

[java] view plain copy public class FileUtil {  
  
    /** 
     * 将文件输出到客户端，一般用于预览 
     * @param file 
     * @param contentType   图片    image/jpeg 
     *                      视频   audio/mpeg 
     *                      应用程序   application/octet-stream 
     */  
    public static void renderFileToClient(File file, String contentType) {  
        OutputStream toClient = null;  
        InputStream fis = null;  
        byte[] buffer = null;  
        HttpServletResponse response = SpringMVCUtil.getResponse();  
        try {  
            fis = new BufferedInputStream(new FileInputStream(file));  
            buffer = new byte[1024];  
            response.reset();  
            response.setContentLength(Long.valueOf(file.length()).intValue());  
            response.setContentType(contentType);  
            response.setHeader("Pragma", "No-cache");  
            response.setHeader("Cache-Control", "no-cache");  
            toClient = new BufferedOutputStream(response.getOutputStream());  
            int bytesRead;  
            while (-1 != (bytesRead = fis.read(buffer, 0, buffer.length))) {  
                toClient.write(buffer, 0, bytesRead);  
                toClient.flush();  
            }  
        } catch (Exception ex) {  
            ex.printStackTrace();  
        } finally {  
            if (fis != null) {  
                try {  
                    fis.close();  
                } catch (IOException e) {  
                    e.printStackTrace();  
                }  
            }  
            if (toClient != null) {  
                try {  
                    toClient.close();  
                } catch (IOException e) {  
                    e.printStackTrace();  
                }  
            }  
        }  
    }  
      
    /** 
     * 获取附件存储相对路径 
     *  
     * @param attachmentConfig 
     * @return 
     */  
    public static String getRelativePath() {  
        StringBuilder sBuilder=new StringBuilder();  
        // 模块名未定  
        String dateStr = DateUtil.getCurrDateString().replaceAll("-", "");  
        sBuilder.append(dateStr.substring(0, 4) + "/");  
        sBuilder.append(dateStr.substring(4, 6) + "/");  
        sBuilder.append(dateStr.substring(6, 8) + "/");  
  
        return sBuilder.toString();  
    }  
      
    /** 
     * 获取临时目录 
     *  
     * @return 
     */  
    public static String getTempDir() {  
        String tempPath = System.getProperty("java.io.tmpdir");  
        File tempFile = new File(tempPath);  
        if (!tempFile.exists()) {  
            tempFile.mkdirs();  
        }  
        return tempFile.getAbsolutePath() + "/";  
    }  
      
    /** 
     * 下载文件 
     *  
     * @date 2015-8-25 下午9:13:13 
     * @param srcPath 
     */  
    public static void download(String downLoadPath) {  
        HttpServletResponse response = SpringMVCUtil.getResponse();  
        response.setContentType("text/html;charset=utf-8");     
        response.setCharacterEncoding("UTF-8");     
        BufferedInputStream bis = null;     
        BufferedOutputStream bos = null;  
        File file = new File(downLoadPath);  
        try {     
            response.setContentType("application/x-msdownload;");     
            response.setHeader("Content-disposition", "attachment; filename="+ new String(file.getName().getBytes("utf-8"), "ISO8859-1"));     
            response.setHeader("Content-Length", String.valueOf(file.length()));     
            bis = new BufferedInputStream(new FileInputStream(downLoadPath));     
            bos = new BufferedOutputStream(response.getOutputStream());     
            byte[] buff = new byte[2048];     
            int bytesRead;     
            while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {     
                bos.write(buff, 0, bytesRead);     
            }     
        } catch (Exception e) {     
            e.printStackTrace();     
        } finally {     
            if (bis != null)  
                try {  
                    bis.close();  
                } catch (IOException e) {  
                    e.printStackTrace();  
                }     
            if (bos != null)  
                try {  
                    bos.close();  
                } catch (IOException e) {  
                    e.printStackTrace();  
                }     
        }     
    }  
      
    /** 
     * 向客户端输出浏览内容 
     * 
     * @date 2015-8-31 下午8:10:48 
     * @param file  视频文件 
     * @param contentType  "audio/mpeg" 
     */  
    public static void renderMediaToClient(File file, String contentType) {  
        OutputStream toClient = null;  
        InputStream fis = null;  
        byte[] buffer = null;  
        HttpServletResponse response = SpringMVCUtil.getResponse();  
        try {  
            fis = new BufferedInputStream(new FileInputStream(file));  
            buffer = new byte[1024];  
            response.reset();  
            response.setContentLength(Long.valueOf(file.length()).intValue());  
            response.setContentType(contentType);  
            response.setHeader("Pragma", "No-cache");  
            response.setHeader("Cache-Control", "no-cache");  
            toClient = new BufferedOutputStream(response.getOutputStream());  
            int bytesRead;  
            while (-1 != (bytesRead = fis.read(buffer, 0, buffer.length))) {  
                toClient.write(buffer, 0, bytesRead);  
                toClient.flush();  
            }  
        } catch (Exception ex) {  
            ex.printStackTrace();  
        } finally {  
            if (fis != null) {  
                try {  
                    fis.close();  
                } catch (IOException e) {  
                    e.printStackTrace();  
                }  
            }  
            if (toClient != null) {  
                try {  
                    toClient.close();  
                } catch (IOException e) {  
                    e.printStackTrace();  
                }  
            }  
        }  
    }  
}