java io流 图片和字符串之间的转换

package com.yundongsports.arena.controller.basketballsite;

import com.yundongsports.arena.ResponseVo.Response;
import org.apache.commons.io.IOUtils;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;
import javax.servlet.http.HttpServletRequest;
import java.io.*;
import java.util.Date;
import java.util.Map;
import java.util.Properties;

/**
 * Created by CF on 2016/12/23.
 */
@Controller
public class ImageUploadController {

    @Value("${base.web.url}")
    private String serverHost;
    /**
     * 将字符串转为图片
     * @param
     * @return
     */
    @RequestMapping(method = RequestMethod.POST, value = "/api/v1/imageUpload")
    @ResponseBody
    public Map<String,Object> generateImage(@RequestParam(value = "upload", required = false) MultipartFile uploadFile,
                                            HttpServletRequest req)throws Exception {
        Response response = new Response();
        System.out.println(uploadFile.getOriginalFilename()+"##"+serverHost);
        String imgFilePath = req.getServletContext().getRealPath("/") ;
        String img= "img/";

        String name=new Date().getTime()+uploadFile.getOriginalFilename();
        File file =new File(imgFilePath+img);
        //如果文件夹不存在则创建
        if  (!file .exists()  && !file .isDirectory()){
            file.mkdir();
        }
        InputStream input = null;
        OutputStream out = null;
        try {
            input = uploadFile.getInputStream();
            out = new FileOutputStream(imgFilePath+img+name);
            IOUtils.copy(input,out);
            out.flush();
            out.close();
            input.close();
        } catch (Exception e) {
            throw e;
        }finally{
            IOUtils.closeQuietly(input);
            IOUtils.closeQuietly(out);
        }
        String url=serverHost+img+name;
        System.out.println("服务器的绝对路径-------------------"+url);
        response.put("data",url);
        response.setResult(Response.TYPE.SUCCESS);
        return response.getResult();
    }

}