时间:2020-12-22 18:20:36 | 栏目:JAVA代码 | 点击:次
本文实例为大家分享了java实现批量下载的具体代码,供大家参考,具体内容如下
现在的需求的:
根据产品族、产品类型,下载该产品族、产品类型下面的pic包;
pic包是zip压缩文件;
t_product表:
这些包以blob形式存在另一张表中:
t_imagefile表:
现在要做的是:将接入网、OLT下面的两个包downloadPIC:MA5800系列-pic.zip 和 MA5900-pic.rar一起打包成zip压缩文件下载下来;
代码:
ProductController.java:
/** * 根据产品族、产品类型下载照片包 */ @RequestMapping("/downloadwBatch") public void downloadwBatch(HttpServletRequest request, HttpServletResponse response, String productFamily, String productType){ //http://localhost:8080/MySSM/downloadwBatch?productFamily=接入网&productType=OLT try { productFamily = new String(productFamily.getBytes("iso-8859-1"), "utf-8"); productType = new String(productType.getBytes("iso-8859-1"), "utf-8"); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } //获取要下载的照片包名 Map<String, String> params = new HashMap<String, String>(); params.put("productFamily", productFamily); params.put("productType", productType); List<String> packageNames = productService.getPackageNamesByFamilyAndType(params); //根据包名获取待下载的文件 文件名-字节数组的形式 Map<String, byte[]> files = new HashMap<String, byte[]>(); for(String packageName : packageNames){ byte[] f = productService.getPackage(packageName); if(f!=null){ files.put(packageName, f); } } //设置下载的压缩包名 String zipName = productFamily + "_"+ productType + ".zip"; //根据文件,进行压缩,批量下载 if(files.size() > 0){ productService.downloadBatchByFile(response, files, zipName); } }
ProductService.java:
/** * 根据包名获取文件 */ public byte[] getPackage(String packageName){ byte[] bag = null; try{ ImageFile m = productMapper.getPackage(packageName); if(m!=null){ bag = m.getPicture(); } }catch(Exception e){ e.printStackTrace(); } return bag; } /** * 根据产品族、产品类型 获取待下载的包名 * @param params * @return */ public List<String> getPackageNamesByFamilyAndType(Map<String, String> params) { List<String> packageNames = productMapper.getPackageNamesByFamilyAndType(params); return packageNames; } /** * 根据文件,进行压缩,批量下载 * @param response * @param files * @throws Exception */ public void downloadBatchByFile(HttpServletResponse response, Map<String, byte[]> files, String zipName){ try{ response.setContentType("application/x-msdownload"); response.setHeader("content-disposition", "attachment;filename="+URLEncoder.encode(zipName, "utf-8")); ZipOutputStream zos = new ZipOutputStream(response.getOutputStream()); BufferedOutputStream bos = new BufferedOutputStream(zos); for(Entry<String, byte[]> entry : files.entrySet()){ String fileName = entry.getKey(); //每个zip文件名 byte[] file = entry.getValue(); //这个zip文件的字节 BufferedInputStream bis = new BufferedInputStream(new ByteArrayInputStream(file)); zos.putNextEntry(new ZipEntry(fileName)); int len = 0; byte[] buf = new byte[10 * 1024]; while( (len=bis.read(buf, 0, buf.length)) != -1){ bos.write(buf, 0, len); } bis.close(); bos.flush(); } bos.close(); }catch(Exception e){ e.printStackTrace(); } }
ProductMapper.java:
/** * 根据包名获取文件 */ public ImageFile getPackage(String packageName) throws Exception; /** * 据产品族、产品类型 获取待下载的包名 */ public List<String> getPackageNamesByFamilyAndType(Map<String, String> params);
ProductMapper.xml:
<!-- 根据包名获取文件 --> <select id="getPackage" parameterType="java.lang.String" resultType="com.cy.model.ImageFile"> select * from t_imagefile where packageName = #{packageName} </select> <!-- 跟据产品族、产品类型 获取待下载的包名 --> <select id="getPackageNamesByFamilyAndType" parameterType="java.util.Map" resultType="java.lang.String"> select packageName from t_imagefile m join t_product p on m.packageName = p.downloadPic where p.productFamily = #{productFamily} and p.productType = #{productType} </select>
测试:
在浏览器中输入:http://localhost:8080/MySSM/downloadwBatch?productFamily=接入网&productType=OLT
下载结果如下:
简单的demo
package com.msznyl; import java.io.BufferedInputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.util.zip.ZipEntry; import java.util.zip.ZipOutputStream; public class Download { public static void main(String[] args) { //需要压缩的文件--包括文件地址和文件名 String [] path ={"E:\\360DocProtect\\01.txt","E:\\360DocProtect\\02.docx"}; // 要生成的压缩文件地址和文件名称 String desPath = "D:\\DOWNLOADS\\new.zip"; File zipFile = new File(desPath); ZipOutputStream zipStream = null; FileInputStream zipSource = null; BufferedInputStream bufferStream = null; try { //构造最终压缩包的输出流 zipStream = new ZipOutputStream(new FileOutputStream(zipFile)); for(int i =0;i<path.length;i++){ File file = new File(path[i]); //将需要压缩的文件格式化为输入流 zipSource = new FileInputStream(file); //压缩条目不是具体独立的文件,而是压缩包文件列表中的列表项,称为条目,就像索引一样 ZipEntry zipEntry = new ZipEntry(file.getName()); //定位该压缩条目位置,开始写入文件到压缩包中 zipStream.putNextEntry(zipEntry); //输入缓冲流 bufferStream = new BufferedInputStream(zipSource, 1024 * 10); int read = 0; //创建读写缓冲区 byte[] buf = new byte[1024 * 10]; while((read = bufferStream.read(buf, 0, 1024 * 10)) != -1) { zipStream.write(buf, 0, read); } } } catch (Exception e) { e.printStackTrace(); } finally { //关闭流 try { if(null != bufferStream) bufferStream.close(); if(null != zipStream) zipStream.close(); if(null != zipSource) zipSource.close(); } catch (IOException e) { e.printStackTrace(); } } } }