第一步 将要下载的多个文件打包成ZIP格式

public String makeZip(List<String> path) throws IOException{

byte[] buffer = new byte[1024];
//创建压缩包路径
String strZipName = "c:/Demo.zip";

ZipOutputStream out = new ZipOutputStream(new FileOutputStream(strZipName));

for(String str:path){
FileInputStream fis = new FileInputStream(file1[i]);
out.putNextEntry(new ZipEntry(str.getName()));
int len;
while((len = fis.read(buffer))>0) {
out.write(buffer,0,len);

}
out.closeEntry();

fis.close();
}
out.close();

return strZipName;
}

第二步 普通的下载

File file = new File(realpath );
String filename = file.getName();

ServletOutputStream out;

response.setContentType("multipart/form-data");
response.setHeader("Content-Disposition", "attachment;fileName="+new String(filename.getBytes("gbk"), "iso-8859-1"));

try {
FileInputStream inputStream = new FileInputStream(file);

//3.通过response获取ServletOutputStream对象(out)
out = response.getOutputStream();

int b = 0;
byte[] buffer = new byte[512];
while ((b=inputStream.read(buffer))>0){

//4.写到输出流(out)中
out.write(buffer,0,b);
}
inputStream.close();
out.close();
out.flush();

} catch (IOException e) {
e.printStackTrace();
}