import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Date;
import java.util.Random;
/**
* Verification code generator
*
* @author
*/
public class ValidateCode {
// The width of the image.
private int width = 160;
// The height of the image.
private int height = 40;
// number of verification code characters
private int codeCount = 5;
// Number of verification code interference lines
private int lineCount = 150;
// verification code
private String code = null;
// verification code image Buffer
private BufferedImage buffImg = null;
// Verification code range, remove 0 (number) and O (pinyin) which are easy to confuse (lowercase 1 and L can also be removed, uppercase is not used)
private char[] codeSequence = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W',
'X', 'Y', 'Z', '1', '2', '3', '4', '5', '6', '7', '8', '9'};
/**
* Default constructor, set default parameters
*/
public ValidateCode() {
this.createCode();
}
/**
* @param width image width
* @param height image height
*/
public ValidateCode(int width, int height) {
this.width = width;
this.height = height;
this.createCode();
}
/**
* @param width image width
* @param height image height
* @param codeCount number of characters
* @param lineCount number of interference lines
*/
public ValidateCode(int width, int height, int codeCount, int lineCount) {
this.width = width;
this.height = height;
this.codeCount = codeCount;
this.lineCount = lineCount;
this.createCode();
}
public void createCode() {
int x = 0, fontHeight = 0, codeY = 0;
int red = 0, green = 0, blue = 0;
x = width / (codeCount + 2);//The width of each character (one character is left on the left and right)
fontHeight = height - 2;//The height of the font
codeY = height - 4;
// image buffer
buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics2D g = buffImg.createGraphics();
// generate random numbers
Random random = new Random();
// fill the image with white
g.setColor(Color.WHITE);
g.fillRect(0, 0, width, height);
// Create font, can be modified to other
Font font = new Font("Fixedsys", Font.PLAIN, fontHeight);
// Font font = new Font("Times New Roman", Font.ROMAN_BASELINE, fontHeight);
g.setFont(font);
for (int i = 0; i < lineCount; i++) {
// set random start and end coordinates
int xs = random.nextInt(width);//start of x coordinate
int ys = random.nextInt(height);//The start of the y coordinate
int xe = xs + random.nextInt(width / 8);//End of x coordinate
int ye = ys + random.nextInt(height / 8);//The end of the y coordinate
// Generate random color values, so that the color value of each output interference line will be different.
red = random.nextInt(255);
green = random.nextInt(255);
blue = random.nextInt(255);
g.setColor(new Color(red, green, blue));
g.drawLine(xs, ys, xe, ye);
}
// randomCode records the randomly generated verification code
StringBuffer randomCode = new StringBuffer();
// Randomly generate a verification code of codeCount characters.
for (int i = 0; i < codeCount; i++) {
String strRand = String.valueOf(codeSequence[random.nextInt(codeSequence.length)]);
// Generate random color values, so that the color value of each character output will be different.
red = random.nextInt(255);
green = random.nextInt(255);
blue = random.nextInt(255);
g.setColor(new Color(red, green, blue));
g.drawString(strRand, (i + 1) * x, codeY);
// Combine the four random numbers generated.
randomCode.append(strRand);
}
// Save the four-digit verification code to the Session.
code = randomCode.toString();
}
public void write(String path) throws IOException {
OutputStream sos = new FileOutputStream(path);
this.write(sos);
}
public void write(OutputStream sos) throws IOException {
ImageIO.write(buffImg, "png", sos);
sos.close();
}
public BufferedImage getBuffImg() {
return buffImg;
}
public String getCode() {
return code;
}
/**
* Test function, generated to d disk by default
* @param args
*/
public static void main(String[] args) {
ValidateCode vCode = new ValidateCode(160,40,5,150);
try {
String path="D:/"+new Date().getTime()+".png";
System.out.println(vCode.getCode()+" >"+path);
vCode.write(path);
} catch (IOException e) {
e.printStackTrace ();
}
}
}
The following is the page call verification code
<div class="form-group col-lg-6">
<label for="id" class="col-sm-4 control-label">
Verification code:
</label>
<div class="col-sm-8">
<input type="text" id="code" name="code" class="form-control" style="width:250px;"/>
<img id="imgObj" alt="验证码" src="/article/validateCode" onclick="changeImg()"/>
<a href="#" onclick="changeImg()">换一张</a>
</div>
</div>
<script type="text/javascript">
// refresh image
function changeImg() {
var imgSrc = $("#imgObj");
var src = imgSrc.attr("src");
imgSrc.attr("src", changeUrl(src));
}
//In order to make the image generated each time inconsistent, that is, to prevent the browser from reading the cache, it is necessary to add a timestamp
function changeUrl(url) {
var timestamp = (new Date()).valueOf();
var index = url.indexOf("?",url);
if (index > 0) {
url = url.substring(0, url.indexOf(url, "?"));
}
if ((url.indexOf("&") >= 0)) {
url = url + "×tamp=" + timestamp;
} else {
url = url + "?timestamp=" + timestamp;
}
return url;
}
</script>
The following is the output verification code of the controller layer
/**
* Response verification code page
* @return
*/
@RequestMapping(value="/validateCode")
public String validateCode(HttpServletRequest request,HttpServletResponse response) throws Exception{
// Set the type format of the response to image format
response.setContentType("image/jpeg");
// Disable image caching.
response.setHeader("Pragma", "no-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
HttpSession session = request.getSession();
ValidateCode vCode = new ValidateCode(120,40,5,100);
session.setAttribute("code", vCode.getCode());
vCode.write(response.getOutputStream());
return null;
}
The following is the controller layer to verify whether the verification code input is correct
String code = request.getParameter("code");
HttpSession session = request.getSession();
String sessionCode = (String) session.getAttribute("code");
if (!StringUtils.equalsIgnoreCase(code, sessionCode)) { //Ignore the case of the verification code
throw new RuntimeException("The verification code does not correspond to code=" + code + " sessionCode=" + sessionCode);
}