写项目的时候写的，感觉以后还会用，所以记录一下

一种通过 java 的get请求获取 网上图片的数据
二种，通过获取本地的具体文件下的图片的数据

前台写的

date.t.avatat 是 存在数据库中 图片的地址
一种是本地地址
一种是 http地址

后台

@RequestMapping("getImagesByAll")
    @ResponseBody
    public void getImagesByAll(HttpServletResponse response, String picture){
          
   

        //设置返回的数据类型
        response.setContentType("image/jpeg;charset=utf-8");
        ServletOutputStream outputStream = null;
        try {
          
   
            outputStream = response.getOutputStream();
        } catch (IOException e) {
          
   
            e.printStackTrace();
        }

        //不是 ./images/xxx.jpg
        if(!picture.startsWith("./")){
          
   
            //通过java实现http的get请求
            try{
          
   
                URL url = new URL(picture);
                HttpURLConnection urlCon= (HttpURLConnection)url.openConnection();

                if(200==urlCon.getResponseCode()){
          
   
                    InputStream is = urlCon.getInputStream();

                    byte[] buffer = new byte[1024];
                    int len =0;

                    while(( len = is.read(buffer)) >0 ){
          
   
                        outputStream.write(buffer,0,len);
                    }

                    outputStream.close();
                    is.close();

                }
            }catch(Exception e){
          
   
                e.printStackTrace();
            }

        }else{
          
   
            //本地服务器中的图片
            //是 ./images/xxx.jpg    D:ideaMyBlogsrcmain
esourcesstaticimagesavatar.jpg
            String pictureName = picture.split("/")[2];
            //打印一下   xxx.jpg
            System.out.println(picture);

            String pictureAddress = "D:\idea\MyBlog\src\main\resources\static\images\"+pictureName;
            //打印一下  D:ideaMyBlogsrcmain
esourcesstaticimagesavatar.jpg
            System.out.println(pictureAddress);

            try {
          
   
                FileInputStream fis = new FileInputStream(pictureAddress);

                byte[] buffer = new byte[1024];
                int len = 0 ;

                //将图片数据想要到浏览器
                while( (len = fis.read(buffer)) > 0    ){
          
   
                    outputStream.write(buffer,0,len);
                }

                fis.close();
                outputStream.close();

            } catch (Exception e) {
          
   
                e.printStackTrace();
            }

        }