java 文件打压缩包下载

 　　项目中需要将多个文件打包成压缩包下载。

　　

　　总共文件是，一个从磁盘读取的文件，其他文件通过url从oss下载的文件，

    @GetMapping("/export/{id}")
    public void exportById(@PathVariable Integer id,HttpServletResponse response) {
        StRecord record = stRecordBiz.selectByPrimaryKey(id);
        String filename="单证"+record.getDiagnosisNo();
        //xls url
        StringBuffer xls = new StringBuffer();
        //准备zip
        OutputStream outputStream = null;
        ZipOutputStream zos = null; //导出的zip输出流
        BufferedInputStream bis = null;//从磁盘读文件缓冲
        FileInputStream wordIs = null;//从磁盘读文件

        //导出word
        String wordName = filePath+filename+".doc";//从磁盘读取文件的文件名
        ZipEntry entry = new ZipEntry(filename+".doc"); //压缩包中的每一个文件是一个zip
        int len;
        File file = new File(wordName);
        try{
　　　　　　　　//一下代码是从磁盘读取文件，输出到zip的输出流里
            outputStream = response.getOutputStream();
            zos = new ZipOutputStream(outputStream);
            wordIs = new FileInputStream(file);
            byte[] buffer = new byte[1024*4];
            bis = new BufferedInputStream(wordIs);
            zos.putNextEntry(entry);
            while ((len = bis.read(buffer)) != -1){
                zos.write(buffer,0,len);
            }
        } catch (IOException e) {
            log.error("zip 错误", e);
        }finally {
            if (entry !=null){
                try {
                    zos.closeEntry();
                } catch (IOException e) {
                    log.error(" entry 关闭异常", e);
                }
            }
            try {
                bis.close();
            } catch (IOException e) {
                log.error("BufferedInputStream 关闭异常", e);
            }
            try {
                wordIs.close();
            } catch (IOException e) {
                log.error("FileInputStream 关闭异常", e);
            }
            file.delete();//删除临时文件
        }
        try {
            //导出excel
            exportExcel(zos,xls); //根据url，输出多个文件
            //返回格式
            response.setContentType("multipart/form-data");
            response.setCharacterEncoding("utf-8");
            response.setHeader("Content-Disposition",
                    "attachment;filename=\"" + new String(filename.getBytes("utf-8"), "iso8859-1") + ".zip\"");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if(zos != null){
                try {
                    zos.close();
                } catch (IOException e) {
                    log.error("zos 关闭异常", e);
                }
            }
            try {
                outputStream.close();
            } catch (IOException e) {
                log.error("outputStream 关闭异常", e);
            }
        }
    }

 

    private void exportExcel(ZipOutputStream zos,StringBuffer xls){
        if(StringUtils.isNotEmpty(xls)){
            String[] split = xls.toString().split(",");
            for (String item:split) {
                ZipEntry entry = new ZipEntry(item);//文件名
                try {
                    zos.putNextEntry(entry);
                    byte[] contentBytes = getFileByte(item);//通过url请求文件，返回文件字节码
                    zos.write(contentBytes);
                } catch (IOException e) {
                    log.error("将excel添加进zip异常", e);
                }finally {
                    if (entry == null) {
                        try {
                            zos.closeEntry();
                        } catch (IOException e) {
                            log.error("entry 关闭异常", e);
                        }
                    }
                }
            }
        }
    }

 

    private byte[] getFileByte(String url){
        HttpClient client = HttpClients.custom().build();
        HttpGet get = new HttpGet(url);
        HttpResponse response;
        try {
            response = client.execute(get);
            if (response.getStatusLine().getStatusCode() == 200) {
                // 得到实体
                HttpEntity entity = response.getEntity();
                byte[] data = EntityUtils.toByteArray(entity);
                return data;
            } else {
                logger.error("下载文件url 错误返回：{}",response);
                return null;
            }
        } catch (IOException e) {
            e.printStackTrace();
            logger.error("下载文件url 错误：",e);
        }
        return null;
    }

 

　总结：注意关闭流时，按照打开的顺序，倒序关闭。