java 后台返回文件流到浏览器

package com.springbootblog.controller;

import io.swagger.annotations.ApiImplicitParam;
import io.swagger.annotations.ApiImplicitParams;
import io.swagger.annotations.ApiOperation;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;

/**
 *@title : JavaClass 
 *@author:zyh
 *@createDate:2018/9/13 21:46
 *
 **/
@RequestMapping(value = "/queryImg")
@Controller
public class ReadImgController {
    @ApiOperation(value = "img", produces = "application/json")
    @ApiImplicitParams({
    })
    @RequestMapping(value = "/img",method = RequestMethod.POST)
    @ResponseBody
    public void getImage(String path, HttpServletRequest request, HttpServletResponse response) {
        try {
            String url="D:\temp-appImg\20180912\7cd2e1a3-a087-4e25-aac8-2bdf8e274c6f.png";
            File file = new File(url);
            String l=request.getRealPath("/")+"/"+url;
            String filename = file.getName();
            InputStream fis = new BufferedInputStream(new FileInputStream(file));
            byte[] buffer = new byte[fis.available()];
            fis.read(buffer);
            fis.close();
            response.reset();
            // 设置response的Header
            response.addHeader("Content-Length", "" + file.length());
            response.setContentType("image/jpg");

            OutputStream toClient = new BufferedOutputStream(response.getOutputStream());
            toClient.write(buffer);
            toClient.flush();
            toClient.close();
        } catch (IOException ex) {
            ex.printStackTrace();
        }
        //return response;
    }

    @ApiOperation(value = "img", produces = "application/json")
    @ApiImplicitParams({
    })
    @RequestMapping(value = "/imgRes",method = RequestMethod.POST)
    @ResponseBody
    public HttpServletResponse  getImageRes(String path, HttpServletRequest request, HttpServletResponse response) {
        try {
            String url="D:\temp-appImg\20180912\7cd2e1a3-a087-4e25-aac8-2bdf8e274c6f.png";
            File file = new File(url);
            String l=request.getRealPath("/")+"/"+url;
            String filename = file.getName();
            InputStream fis = new BufferedInputStream(new FileInputStream(file));
            byte[] buffer = new byte[fis.available()];
            fis.read(buffer);
            fis.close();
            response.reset();
            // 设置response的Header
            response.addHeader("Content-Length", "" + file.length());
            response.setContentType("image/png");

            OutputStream toClient = new BufferedOutputStream(response.getOutputStream(),888888);
            toClient.write(buffer);
            toClient.flush();
            toClient.close();
        } catch (IOException ex) {
            ex.printStackTrace();
        }
        return response;
    }
    @ApiOperation(value = "返回指定地址的文件流1")
    @ApiImplicitParams({
            @ApiImplicitParam(name = "url", value = "图片地址", required = true,
                    paramType = "query", defaultValue = "\20180912\7cd2e1a3-a087-4e25-aac8-2bdf8e274c6f.png"),
    })
    @RequestMapping(value = "/noLogin/readImageFile1", method = RequestMethod.POST)
    @ResponseBody
    public void getUrlFile(String url, HttpServletRequest request, HttpServletResponse response) {
        String serverUrl = "D:\temp-appImg\";
        String imgUrl = serverUrl + url;
        File file = new File(imgUrl);
        // 后缀名
        String suffixName = url.substring(url.lastIndexOf("."));
        String imgType = "image/" + suffixName;
        //判断文件是否存在如果不存在就返回默认图标
        if (!(file.exists() && file.canRead())) {
            file = new File(request.getSession().getServletContext().getRealPath("/")
                    + "resource/icons/auth/root.png");
        }
        FileInputStream inputStream = null;
        try {
            inputStream = new FileInputStream(file);
            byte[] data = new byte[(int) file.length()];
            int length = inputStream.read(data);
            inputStream.close();
            //setContentType("text/plain; charset=utf-8"); 文本
            response.setContentType(imgType + ";charset=utf-8");
            OutputStream stream = response.getOutputStream();
            stream.write(data);
            stream.flush();
            stream.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}