js+java实现登录滑动图片验证

最新需要公司要求在不改变原来的登录逻辑的情况下，将原来的验证码登录的形式改成滑动图片的形式！下面是做出来的效果：

实现思路：所有的图片数据，验证全部由后端来做。前端调用接口，后端会返回两张经过base64加密的图片信息，分别是背景图片和滑块图片，前端滑动滑块以后将X方向的滑动距离传回后端做验证，验证成功以后再做后续的登录逻辑验证，以下是完整的过程：

获取背景图，我这边是在FTP上放了10张图片，随机获取一张。

@LogAnnotation(description = "web获取滑动图片信息")
@ApiOperation(value = "web获取滑动图片信息", httpMethod = "POST", response = Result.class, notes = "")
@RequiresPermissions(value = "code/picture/msg")
@RequestMapping(value = "code/picture/msg", method = RequestMethod.POST)
@ResponseBody
public Response getPictureCode(HttpServletRequest request) {
Map<String, Object> pictureMap = new HashMap<>();
try {
//随机获取需要切成的图片形状
Integer templateNum = new Random().nextInt(10) + 1;
String randomStr = String.valueOf(templateNum);
if(templateNum < 10){
randomStr = "0"+randomStr;
}
InputStream tempInputStream = FileUtils.downloadFtpFile(Constant.POCTURE_CHECK_PATH,randomStr+".jpg");
//根据源图片和抠图形状生成新的图片信息以流的形式返回到前端
pictureMap = VerifyImageUtil.getVerifyImage(tempInputStream);
//将剪裁好了以后的图片信息以当前时间戳为key，存入redis（这一步是为了对图片信息做过期处理，根据自己需求做）
String tempTime = String.valueOf(System.currentTimeMillis());
redisUtils.hset(Constant.REDIS_LOGIN_PICTURE_CODE, tempTime,pictureMap.get("locationX").toString(),60);
pictureMap.put("tempTime",tempTime);
//移出随机生成的抠图位置坐标，不返回给前端
pictureMap.remove("locationX");
return new ObjectResponse<Map<String, Object>>(pictureMap);
}catch(Exception e){
logger.error("code/picture/msg", e);
return new FailedResponse();
}
}

FTP下载方法代码

public static FTPClient ftpLogin(){
String ip = p.getProperty("ftp的ip");
String username = p.getProperty("ftp的user");
String password = p.getProperty("ftp的pwd");
int ftpPort = Integer.parseInt(p.getProperty("ftp的port"));
FTPClient ftpClient = new FTPClient();
try {
 ftpClient.connect(ip , ftpPort );// 连接FTP服务器
 ftpClient.login(username , password );// 登陆FTP服务器
 if (!FTPReply.isPositiveCompletion(ftpClient.getReplyCode())) {
 ftpClient.disconnect();
 }
} catch (SocketException e) {
 e.printStackTrace();
} catch (IOException e) {
 e.printStackTrace();
}
return ftpClient;
}

public static InputStream downloadFtpFile(String ftpPath, String fileName) {
FTPClient ftpClient = ftpLogin();
try {
 ftpClient.setControlEncoding("UTF-8"); // 中文支持
 ftpClient.setFileType(FTPClient.BINARY_FILE_TYPE);
 ftpClient.enterLocalPassiveMode();
 ftpClient.changeWorkingDirectory(ftpPath);
 InputStream inputStream = ftpClient.retrieveFileStream(new String(fileName.getBytes("UTF-8"), "ISO-8859-1"));
 //ftpClient.completePendingCommand();
 return inputStream;
} catch (Exception e) {
 e.printStackTrace();
}finally {
 try {
ftpClient.logout();
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}

抠图工具类VerifyImageUtil

public class VerifyImageUtil {

/**
* 源文件宽度
*/
private static int ORI_WIDTH = 296;
/**
* 源文件高度
*/
private static int ORI_HEIGHT = 182;
/**
* 模板图宽度
*/
private static int CUT_WIDTH = 50;
/**
* 模板图高度
*/
private static int CUT_HEIGHT = 50;
/**
* 抠图凸起圆心
*/
private static int circleR = 6;
/**
* 抠图内部矩形填充大小
*/
private static int RECTANGLE_PADDING = 6;
/**
* 抠图的边框宽度
*/
private static int SLIDER_IMG_OUT_PADDING = 1;

/**
* 根据传入的路径生成指定验证码图片
*
* @param filePath
* @return
* @throws IOException
*/
public static Map<String, Object> getVerifyImage(InputStream filePath) throws IOException {
BufferedImage srcImage = ImageIO.read(filePath);
int locationX = CUT_WIDTH + new Random().nextInt(srcImage.getWidth() - CUT_WIDTH * 2);
int locationY = CUT_HEIGHT + new Random().nextInt(srcImage.getHeight() - CUT_HEIGHT) / 2;
BufferedImage markImage = new BufferedImage(CUT_WIDTH,CUT_HEIGHT,BufferedImage.TYPE_4BYTE_ABGR);
int[][] data = getBlockData();
cutImgByTemplate(srcImage, markImage, data, locationX, locationY);
Map<String, Object> resultMap = new HashMap<>();
//放入背景图的加密信息
resultMap.put("srcImage",getImageBASE64(srcImage));
//放入滑块图的加密信息
resultMap.put("markImage",getImageBASE64(markImage));
//放入抠图位置的X方向的信息，用于验证滑块位置是否正确
resultMap.put("locationX",locationX);
//放入抠图位置的Y方向的信息，用于前端控制定位信息
resultMap.put("locationY",locationY);
return resultMap;
}

/**
* 生成随机滑块形状
* <p>
* 0 透明像素
* 1 滑块像素
* 2 阴影像素
* @return int[][]
*/
private static int[][] getBlockData() {
int[][] data = new int[CUT_WIDTH][CUT_HEIGHT];
Random random = new Random();
//(x-a)&sup2;+(y-b)&sup2;=r&sup2;
//x中心位置左右5像素随机
double x1 = RECTANGLE_PADDING + (CUT_WIDTH - 2 * RECTANGLE_PADDING) / 2.0 - 5 + random.nextInt(10);
//y 矩形上边界半径-1像素移动
double y1_top = RECTANGLE_PADDING - random.nextInt(3);
double y1_bottom = CUT_HEIGHT - RECTANGLE_PADDING + random.nextInt(3);
double y1 = random.nextInt(2) == 1 ? y1_top : y1_bottom;

double x2_right = CUT_WIDTH - RECTANGLE_PADDING - circleR + random.nextInt(2 * circleR - 4);
double x2_left = RECTANGLE_PADDING + circleR - 2 - random.nextInt(2 * circleR - 4);
double x2 = random.nextInt(2) == 1 ? x2_right : x2_left;
double y2 = RECTANGLE_PADDING + (CUT_HEIGHT - 2 * RECTANGLE_PADDING) / 2.0 - 4 + random.nextInt(10);

double po = Math.pow(circleR, 2);
for (int i = 0; i < CUT_WIDTH; i++) {
for (int j = 0; j < CUT_HEIGHT; j++) {
//矩形区域
boolean fill;
if ((i >= RECTANGLE_PADDING && i < CUT_WIDTH - RECTANGLE_PADDING)
&& (j >= RECTANGLE_PADDING && j < CUT_HEIGHT - RECTANGLE_PADDING)) {
data[i][j] = 1;
fill = true;
} else {
data[i][j] = 0;
fill = false;
}
//凸出区域
double d3 = Math.pow(i - x1, 2) + Math.pow(j - y1, 2);
if (d3 < po) {
data[i][j] = 1;
} else {
if (!fill) {
data[i][j] = 0;
}
}
//凹进区域
double d4 = Math.pow(i - x2, 2) + Math.pow(j - y2, 2);
if (d4 < po) {
data[i][j] = 0;
}
}
}
//边界阴影
for (int i = 0; i < CUT_WIDTH; i++) {
for (int j = 0; j < CUT_HEIGHT; j++) {
//四个正方形边角处理
for (int k = 1; k <= SLIDER_IMG_OUT_PADDING; k++) {
//左上、右上
if (i >= RECTANGLE_PADDING - k && i < RECTANGLE_PADDING
&& ((j >= RECTANGLE_PADDING - k && j < RECTANGLE_PADDING)
|| (j >= CUT_HEIGHT - RECTANGLE_PADDING - k && j < CUT_HEIGHT - RECTANGLE_PADDING +1))) {
data[i][j] = 2;
}

//左下、右下
if (i >= CUT_WIDTH - RECTANGLE_PADDING + k - 1 && i < CUT_WIDTH - RECTANGLE_PADDING + 1) {
for (int n = 1; n <= SLIDER_IMG_OUT_PADDING; n++) {
if (((j >= RECTANGLE_PADDING - n && j < RECTANGLE_PADDING)
 || (j >= CUT_HEIGHT - RECTANGLE_PADDING - n && j <= CUT_HEIGHT - RECTANGLE_PADDING ))) {
data[i][j] = 2;
}
}
}
}

if (data[i][j] == 1 && j - SLIDER_IMG_OUT_PADDING > 0 && data[i][j - SLIDER_IMG_OUT_PADDING] == 0) {
data[i][j - SLIDER_IMG_OUT_PADDING] = 2;
}
if (data[i][j] == 1 && j + SLIDER_IMG_OUT_PADDING > 0 && j + SLIDER_IMG_OUT_PADDING < CUT_HEIGHT && data[i][j + SLIDER_IMG_OUT_PADDING] == 0) {
data[i][j + SLIDER_IMG_OUT_PADDING] = 2;
}
if (data[i][j] == 1 && i - SLIDER_IMG_OUT_PADDING > 0 && data[i - SLIDER_IMG_OUT_PADDING][j] == 0) {
data[i - SLIDER_IMG_OUT_PADDING][j] = 2;
}
if (data[i][j] == 1 && i + SLIDER_IMG_OUT_PADDING > 0 && i + SLIDER_IMG_OUT_PADDING < CUT_WIDTH && data[i + SLIDER_IMG_OUT_PADDING][j] == 0) {
data[i + SLIDER_IMG_OUT_PADDING][j] = 2;
}
}
}
return data;
}

/**
* 裁剪区块
* 根据生成的滑块形状，对原图和裁剪块进行变色处理
* @param oriImage 原图
* @param targetImage 裁剪图
* @param blockImage 滑块
* @param x  裁剪点x
* @param y  裁剪点y
*/
private static void cutImgByTemplate(BufferedImage oriImage, BufferedImage targetImage, int[][] blockImage, int x, int y) {
for (int i = 0; i < CUT_WIDTH; i++) {
for (int j = 0; j < CUT_HEIGHT; j++) {
int _x = x + i;
int _y = y + j;
int rgbFlg = blockImage[i][j];
int rgb_ori = oriImage.getRGB(_x, _y);
// 原图中对应位置变色处理
if (rgbFlg == 1) {
//抠图上复制对应颜色值
targetImage.setRGB(i,j, rgb_ori);
//原图对应位置颜色变化
oriImage.setRGB(_x, _y, rgb_ori & 0x363636);
} else if (rgbFlg == 2) {
targetImage.setRGB(i, j, Color.WHITE.getRGB());
oriImage.setRGB(_x, _y, Color.GRAY.getRGB());
}else if(rgbFlg == 0){
//int alpha = 0;
targetImage.setRGB(i, j, rgb_ori & 0x00ffffff);
}
}

}
}

/**
* 随机获取一张图片对象
* @param path
* @return
* @throws IOException
*/
public static BufferedImage getRandomImage(String path) throws IOException {
File files = new File(path);
File[] fileList = files.listFiles();
List<String> fileNameList = new ArrayList<>();
if (fileList!=null && fileList.length!=0){
for (File tempFile:fileList){
if (tempFile.isFile() && tempFile.getName().endsWith(".jpg")){
fileNameList.add(tempFile.getAbsolutePath().trim());
}
}
}
Random random = new Random();
File imageFile = new File(fileNameList.get(random.nextInt(fileNameList.size())));
return ImageIO.read(imageFile);
}

/**
* 将IMG输出为文件
* @param image
* @param file
* @throws Exception
*/
public static void writeImg(BufferedImage image, String file) throws Exception {
byte[] imagedata = null;
ByteArrayOutputStream bao=new ByteArrayOutputStream();
ImageIO.write(image,"png",bao);
imagedata = bao.toByteArray();
FileOutputStream out = new FileOutputStream(new File(file));
out.write(imagedata);
out.close();
}

/**
* 将图片转换为BASE64
* @param image
* @return
* @throws IOException
*/
public static String getImageBASE64(BufferedImage image) throws IOException {
ByteArrayOutputStream out = new ByteArrayOutputStream();
ImageIO.write(image,"png",out);
//转成byte数组
byte[] bytes = out.toByteArray();
BASE64Encoder encoder = new BASE64Encoder();
//生成BASE64编码
return encoder.encode(bytes);
}

/**
* 将BASE64字符串转换为图片
* @param base64String
* @return
*/
public static BufferedImage base64StringToImage(String base64String) {
try {
BASE64Decoder decoder=new BASE64Decoder();
byte[] bytes1 = decoder.decodeBuffer(base64String);
ByteArrayInputStream bais = new ByteArrayInputStream(bytes1);
return ImageIO.read(bais);
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
}

前端收到请求成功返回信息以后，对数据做解析

// 设置图片的src属性
$("#背景图的ID").attr("src", "data:image/png;base64," + result.datas.srcImage);
$("#滑块图的ID").attr("src", "data:image/png;base64," + result.datas.markImage);
$("#滑块图的ID").css("top", result.datas.locationY);
/* 初始化按钮拖动事件 */
// 鼠标点击事件
$("#滑块拖动条").mousedown(function(e) {
e = e || window.event;
// 鼠标在滑块按下切换滑块背景
var left = e.pageX;//记录鼠标按下时的坐标 X轴值
var num = 0;
// 鼠标移动事件
document.onmousemove = function(e) {
var nowLeft = e.pageX;
num = nowLeft-left;
if(num <= 0){
num = 0;
}else if(num >= 251){
num= 251;
}
$("#滑块拖动条").css("width", (42+num) + "px");
$("#滑块拖动条图片").css("left", (num) + "px");
$("#滑块拖动条").css("background-color", "#3c55ff");
};
// 鼠标松开事件
document.onmouseup = function(e) {
left = 0;
document.onmousemove = null;
document.onmouseup = null;
  //松开以后进行后续的验证......

};
});

来源：https://blog.csdn.net/qq_38400856/article/details/104915350