String AND Image Conversion

本文介绍如何使用Java实现图片文件与Base64编码之间的相互转换,包括从前端接收上传的图片文件并保存为Base64编码字符串,以及如何将Base64字符串还原为图片文件。

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    /*<form action="<%=basePath%>/file/test1" method="post" enctype="multipart/form-data">
        <input type="file" name="multipartFile" value="fileValues">
        <input type="submit" value="提交" style="height: 35px; ">
     </form>*/


    //  上下文是要对应的。。名字一定要一样name.multipartFile= MultipartFile.multipartFile
    @RequestMapping("/test1")
    public void runwer(MultipartFile multipartFile) throws Exception {
        byte[] data = multipartFile.getBytes();
        BASE64Encoder encoder = new BASE64Encoder();
        String encode = encoder.encode(data);//返回Base64编码过的字节数组字符串
        PrintWriter writer = new PrintWriter("D://qqqqqqqqqqqqqqq//test//abc.txt", "UTF-8");
        writer.println(encode);
        writer.close();
        System.out.println("+++++++++++++++++++++");
        // base64字符串转化成图片
        boolean a = GenerateImage(encode);
        System.out.println(a);
    }




    //图片转化成base64字符串
    public static String GetImageStr() {
        //将图片文件转化为字节数组字符串,并对其进行Base64编码处理
        String imgFile = "D://qqqqqqqqqqqqqqq//test//wx_camera_1523021056870.jpg";//待处理的图片
        InputStream in = null;
        byte[] data = null;
        //读取图片字节数组
        try {
            in = new FileInputStream(imgFile);
            data = new byte[in.available()];
            in.read(data);
            in.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        //对字节数组Base64编码
        BASE64Encoder encoder = new BASE64Encoder();
        return encoder.encode(data);//返回Base64编码过的字节数组字符串
    }




    //base64字符串转化成图片
    public static boolean GenerateImage(String imgStr)
    {   //对字节数组字符串进行Base64解码并生成图片
        if (imgStr == null) { //图像数据为空
            return false;
        }
        BASE64Decoder decoder = new BASE64Decoder();
        try {//Base64解码
            byte[] b = decoder.decodeBuffer(imgStr);
            for(int i=0;i<b.length;++i) {
                if(b[i]<0) {//调整异常数据
                    b[i]+=256;
                }
            }
            //生成jpg图片
            String imgFilePath = "D://qqqqqqqqqqqqqqq//test//222.jpg";//新生成的图片
            OutputStream out = new FileOutputStream(imgFilePath);
            out.write(b);
            out.flush();
            out.close();
            return true;
        } catch (Exception e) {
            return false;
        }
    }
Develop an image converter viewer application, to perform the following. The input image must be converted into (a) grayscale image, (b) negative image, (c) red image, (d) green image, (e) blue image, (f) Sepia image, (g) mirror image and (d) image with watermark with words “@UPC 2025”. Display resulting images one after another with 5-seconds of delay between each. Here is an example is provided, where the program converts an image (Test1.jpg) to grayscale (Test2.png) and negative (Test3.png) versions, then displays them one after another with a 5-second delay between each. import java.awt.image.BufferedImage; import java.io.File; import java.io.IOException; import javax.imageio.ImageIO; import javax.swing.ImageIcon; import javax.swing.JFrame; import javax.swing.JLabel; import java.awt.FlowLayout; public class ImageConverterViewer { public static void main(String args[]) throws IOException, InterruptedException { // Load the original image BufferedImage originalImg = null; File f = null; try { f = new File("C:/Images/Test1.jpg"); originalImg = ImageIO.read(f); } catch (IOException e) { System.out.println(e); return; } // Create grayscale image BufferedImage grayImg = createGrayscaleImage(originalImg); saveImage(grayImg, "C:/Images/Test2.png", "Grayscale conversion complete."); // Create negative image BufferedImage negativeImg = createNegativeImage(originalImg); saveImage(negativeImg, "C:/Images/Test3.png", "Negative conversion complete."); // Display images one after another displayImagesWithDelay(originalImg, grayImg, negativeImg); } private static BufferedImage createGrayscaleImage(BufferedImage img) { int width = img.getWidth(); int height = img.getHeight(); BufferedImage grayImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
最新发布
07-19
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