SpringMVC - 12.SpringMVC(文件下载） - 《Java笔记》

TestController

package controller;
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.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import java.io.File;
import java.io.IOException;
@Controller
public class TestController {
    /**
     * 原生方式
     *
     * @RequestMapping("download.do") public void download(HttpServletRequest request,HttpServletResponse response) throws Exception {
     * //1.获取请求传递过来的文件名
     * String fileName = request.getParameter("fileName");
     * //2.直接创建文件输入流读取文件
     * InputStream inputStream = new FileInputStream("D://test//"+fileName);
     * //3.做响应啦----设置
     * //  如果服务端存储的文件名字含有中文，需要处理一下
     * fileName = URLEncoder.encode(fileName,"UTF-8");
     * //  响应信息头
     * response.setContentType("application/x-msdownload");
     * response.setHeader("Content-disposition","attachment;filename="+fileName);
     * //4.正式开始写数据(输出流)
     * OutputStream outputStream = response.getOutputStream();
     * byte[] b = new byte[1024];
     * int length = inputStream.read(b);//读取有效字节个数
     * while(length!=-1){
     * outputStream.write(b,0,length);
     * outputStream.flush();
     * length = inputStream.read(b);
     * }
     * }
     * @return
     */
    //基于SpringMVC方式实现文件下载
    @RequestMapping("download.do")
    public ResponseEntity download(String fileName) throws IOException {//fileName变量 名字是框架帮我们注入进去的  帮我们组合成了String
        //读取文件
        File file = new File("D://" + fileName);
        //设置响应信息相关
        //如果有中文，需要处理    new String(byte[],"字符集")
        fileName = new String(fileName.getBytes("UTF-8"), "ISO-8859-1");
        //响应信息头
        HttpHeaders headers=new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
        headers.setContentDispositionFormData("attachment",fileName);
        //将响应信息存入一个返回值对象内即可----ResponseEntity
        byte[] b= FileUtils.readFileToByteArray(file);
        return new ResponseEntity(b,headers, HttpStatus.CREATED);
    }
}

index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
  <head>
  </head>
  <body>

    <a href="download.do?fileName=服务外包作业1.docx">download</a>

  </body>
</html>