javaio

1.本地图片文件转成Base64字符串

InputStream in = new FileInputStream(imgFilePath);

 data = new byte[in.available()];

BASE64Encoder encoder = new BASE64Encoder();

   return encoder.encode(data);

2.本地图片转成InputStream流对象

BASE64Decoder decoder = new BASE64Decoder();

byte[] bytes1 = decoder.decodeBuffer(base64string);  

ByteArrayInputStream  stream = new ByteArrayInputStream(bytes1);  

3.本地图片转成BufferedImage流（base64string通过1可以得到）

InputStream stream = BaseToInputStream(base64string);

BufferedImage image = ImageIO.read(stream);

4.图片文件保存（imgStrBase64编码的字符串）

BASE64Decoder decoder = new BASE64Decoder();

 // Base64解码

byte[] bytes = decoder.decodeBuffer(imgStr);

            for (int i = 0; i < bytes.length; ++i) {

                if (bytes[i] < 0) {// 调整异常数据

                    bytes[i] += 256;

                }

            }

            // 生成jpeg图片

            OutputStream out = new FileOutputStream(imgFilePath);

            out.write(bytes);

5.jsp将图片显示到页面

out.clear();

response.setContentType("image/jpg");

BufferedImage image = ImageIO.read(new File("D:\\201804000009-vDr8ZG.JPG"));

ImageIO.write(image, "jpg", response.getOutputStream());

6.jsp或html下载文件

/ 设置浏览器以下载的方式处理该文件名

response.setHeader("Content-Disposition", "attachment;filename="

.concat(String.valueOf(URLEncoder.encode(fileName, "UTF-8"))));

out = response.getOutputStream();

byte[] buffer = new byte[512]; // 缓冲区

int bytesToRead = -1;

// 通过循环将读入的Word文件的内容输出到浏览器中

while((bytesToRead = fin.read(buffer)) != -1) {

out.write(buffer, 0, bytesToRead);

}