写一个简单的文件服务器

1、先简单搭建一个springboot应用

2、写一个文件读取controller

import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.nio.file.Files;
import java.nio.file.Paths;

@RestController
@RequestMapping
public class FileDownloadController {

    // 要被分享的目录
    final String path = "../";

    @GetMapping("")
    public String abc(HttpServletRequest request, HttpServletResponse response) throws UnsupportedEncodingException {
        final String fileName = request.getParameter("fileName");
        if (StringUtils.isEmpty(fileName)) {
            // 文件
            final File file = new File(path);
            final File[] files = file.listFiles();
            if (files == null || files.length == 0) {
                return "分享文件夹没有文件";
            }
            return listFils(files);
        } else {
            // 下载
            final File file = new File(path, fileName);
            response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName, "utf-8"));
            response.setContentType("application/octet-stream");
            try (final ServletOutputStream outputStream = response.getOutputStream()){
                Files.copy(Paths.get(file.getPath()), outputStream);
            } catch (IOException e) {
                e.printStackTrace();
                return "下载出错";
            }
            return "下载完成";
        }
    }

    private String listFils(File[] files) {
        final StringBuilder stringBuffer = new StringBuilder();
        for (File file : files) {
            if (file.isFile()) {
                stringBuffer.append("<a href=\"?fileName="+file.getName()+"\">"+file.getName()+"</a><br/>");
            }
        }
        return stringBuffer.toString();
    }
}

3、直接访问

http://localhost:8080 即可