配置文件

SpringMVC 配置和依赖：https://www.ab62.cn/article/6537.html

文件下载的 Controller

注意：restFul 风格一般会把文件后缀名截取掉, 加上 :.+ 来保留文件后缀名

package com.pro.controller;

import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URLEncoder;

@RestController
public class FileController {

	// 使用restFul风格一般会把文件后缀名截取掉, 加上:.+ 来保留文件后缀名
    @RequestMapping(value = "/download/{fileName:.+}")
    public String download(@PathVariable String fileName, HttpServletResponse response, HttpServletRequest request) throws Exception {
        System.out.println("download --> " + fileName);
        //要下载的图片地址
        String path = request.getServletContext().getRealPath("/upload");

		File file = new File(path, fileName);
		if (!file.exists()) {
            return "文件不存在";
        }

        //1、设置response 响应头
        response.reset(); //设置页面不缓存,清空buffer
        response.setCharacterEncoding("UTF-8"); //字符编码
        response.setContentType("multipart/form-data"); //二进制传输数据
        //设置响应头
        response.setHeader("Content-Disposition", "attachment;fileName=" + URLEncoder.encode(fileName, "UTF-8"));

        //2、 读取文件--输入流
        InputStream input = new FileInputStream(file);
        //3、 写出文件--输出流
        OutputStream out = response.getOutputStream();

        //4、执行 写出操作
        byte[] buff = new byte[1024];
        int index = 0;
        while ((index = input.read(buff)) != -1) {
            out.write(buff, 0, index);
            out.flush();
        }

        // 关闭流
        out.close();
        input.close();
        return null;
    }
}

测试

启动项目访问：http://localhost:8080/download/xxx.xx

我的项目中有一个 aa.pdf 的文件， 就直接访问

http://localhost:8080/download/aa.pdf