Spring MVC 之 文件下载与批量打包下载

　　文件下载大多使用输出流的方式来实现。而SpringMVC 提供了一个ResponseEntity类型，可以很方便地定义返回的HttpHeaders和HttpStatus。

ResponseEntity<byte []>

import java.io.File;
import java.io.IOException;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.io.FileUtils;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

@RequestMapping("/download")
public class DownLoadFile {
	
	@RequestMapping("/mediafile")
	public ResponseEntity<byte []> downloadFile(HttpServletRequest request, HttpServletResponse response, 
			String fileName,Model model) throws IOException{
		
		//获取文件路径
		String filePath = request.getServletContext().getRealPath("/static/img/");
		//解决文件名中文乱码问题
		String downLoadFileName = new String(fileName.getBytes("utf-8"), "ISO8859-1");
		//创建文件对象：路径/文件名，注文件名包含后缀
		File file = new File(filePath + File.separator + fileName);
		
		//设置头消息
		HttpHeaders headers = new HttpHeaders();
		//以附件形式下载
		headers.setContentDispositionFormData("attachment", downLoadFileName);
		//APPLICATION_OCTET_STREAM:二进制流数据
		headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
		
		ResponseEntity<byte[]> responseEntity = new ResponseEntity<byte []>(FileUtils.readFileToByteArray(file),headers,HttpStatus.CREATED);
		
		return responseEntity;
	}
}

输出流方式

使用输出流的方式实现文件下载。

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
@RequestMapping("/admin/download")
public class DownloadController {
	
	/**
	 * Android app下载
	 * 接收下载路径传递 的文件名
	 * @param request
	 * @param response
	 * @param filename
	 * @param contentType
	 * @throws Exception
	 */
	@RequestMapping("/androidapp")
	public void downloadApp(HttpServletRequest request, HttpServletResponse response,String filename,String contentType) throws Exception {  
        
		//编码转换
		response.setContentType("text/html;charset=UTF-8");  
        request.setCharacterEncoding("UTF-8");  
        
        BufferedInputStream bis = null;  
        BufferedOutputStream bos = null;   
  
//      String filename = "app-debug.apk";
        
        //文件下载全路径
        String filePath = request.getServletContext().getRealPath("/updown/app") + File.separator +  filename;
        
        long fileLength = new File(filePath).length();  
        
        response.setContentType(contentType); 
        //处理中文乱码,以附件方式下载
        response.setHeader("Content-disposition", "attachment; filename="+ new String(filename.getBytes("utf-8"), "ISO8859-1"));  
        response.setHeader("Content-Length", String.valueOf(fileLength));  
        
        bis = new BufferedInputStream(new FileInputStream(filePath));  
        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);  
        }  
        bis.close();  
        bos.close();  
    }  
}

批量打包下载

import com.xxx.xxx.xxx.FilesMapper;
import com.xxx.xxx.xxx..mapper.OrderMapper;
import com.xxx.xxx.xxx..model.Files;
import com.xxx.xxx.xxx..model.Order;
import com.xxx.xxx.xxx..service.DownloadService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.List;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

/**
 * @Name: DownloadServiceImpl
 * @Desc: 下载接口实现
 **/
@Service
public class DownloadServiceImpl implements DownloadService {

    @Autowired
    private FilesMapper filesMapper;
    @Autowired
    private OrderMapper orderMapper;

    @Override
    public void batchDownloadOrderFile(HttpServletResponse response, Long orderId) throws IOException {

        try {
            //获取订单附件
            List<Files> filesList = filesMapper.getByOrderId(orderId);
            if (filesList != null && filesList.size() != 0) {
                Order order = orderMapper.getById(orderId);
                //文件名
                String batchDonwloadFileName = order.getOrderNo() + ".zip";
                //指明response的返回对象是文件流
                response.setContentType("application/octet-stream");
                //设置在下载框默认显示的文件名
                response.setHeader("Content-Disposition", "attachment;filename=" + batchDonwloadFileName);
                //打包输出流
                ZipOutputStream zos = new ZipOutputStream(response.getOutputStream());

                for (Files file : filesList) {
                    String downloadUrl = file.getDownloadUrl();
                    URL url = new URL(downloadUrl);
                    int i = downloadUrl.lastIndexOf("/");
                    String fileName = downloadUrl.substring(i + 1, downloadUrl.length());
                    zos.putNextEntry(new ZipEntry(fileName));
                    InputStream inputStream = url.openConnection().getInputStream();
                    byte[] buffer = new byte[1024];
                    int length = 0;
                    while (-1 != (length = inputStream.read(buffer, 0, buffer.length))) {
                        zos.write(buffer, 0, length);
                    }
                    inputStream.close();
                }
                zos.flush();
                zos.close();
            }
        } catch (IOException e) {
            throw e;
        }
    }
}