JAVA实现图片验证码

一、创建image工具类

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.Random;

public class ImageUtil {

// 图片的宽度。
private int width = 160;
// 图片的高度。
private int height = 40;
// 验证码字符个数
private int codeCount = 5;
// 验证码干扰线数
private int lineCount = 150;
// 验证码
private String code = null;

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'};

private BufferedImage bufferedImage;

private ImageUtil(int width, int height){
this.width = width;
this.height = height;
}

public ImageUtil(int width, int height, int codeCount, int lineCount){
this(width, height);
this.codeCount = codeCount;
this.lineCount = lineCount;
createCodeImage();
}
private void createCodeImage(){
//字符所在x坐标
int x = 0;
//字体高度
int fontHeight = 0;
//字符所在y坐标
int codeY = 0;
int red = 0;
int green = 0;
int blue = 0;
x = width / (codeCount + 2);
fontHeight = height - 2;
codeY = height - 4;
bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
Graphics2D graphics2D = bufferedImage.createGraphics();
Random random = new Random();
graphics2D.setColor(Color.WHITE);
graphics2D.fillRect(0, 0, width,height);
Font font = new Font("Fixedays",Font.PLAIN,fontHeight);
graphics2D.setFont(font);

for (int i = 0; i < lineCount; i++) {
//x轴第一个点的位置
int x1 = random.nextInt(width);
//y轴第一个点的位置
int y1 = random.nextInt(height);
//x轴第二个点的位置
int x2 = x1 + random.nextInt(width >> 2);
//y轴第二个点的位置
int y2 = y1 + random.nextInt(height >> 2);

red = random.nextInt(255);
green = random.nextInt(255);
blue = random.nextInt(255);

graphics2D.setColor(new Color(red, green, blue));
graphics2D.drawLine(x1, y1, x2, y2);
}

StringBuffer randomCode = new StringBuffer(codeCount);
for (int i = 0; i < codeCount; i++) {
String strRand = String.valueOf(codeSequence[random.nextInt(codeSequence.length)]);
red = random.nextInt(255);
green = random.nextInt(255);
blue = random.nextInt(255);
graphics2D.setColor(new Color(red, green, blue));
graphics2D.drawString(strRand, (i +1) * x, codeY);
randomCode.append(strRand);
}
code = randomCode.toString();
}

public void write(String path) throws IOException {
OutputStream outputStream = new FileOutputStream(path);
this.write(outputStream);
outputStream.flush();
outputStream.close();
}

public void write(OutputStream outputStream) throws IOException {
ImageIO.write(bufferedImage, "png", outputStream);
}

public BufferedImage getBufferedImage(){
return bufferedImage;
}

public String getCode(){
return code;
}

}
二、controller

@GetMapping(value = "/code")
public String getCode(HttpServletRequest request, HttpServletResponse response) throws Exception{
response.setContentType("image/jpeg");
//禁止图像缓存
response.setHeader("Pragma","no-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
HttpSession session = request.getSession();
ImageUtil imageUtil = new ImageUtil(120, 40, 5,30);
session.setAttribute("code", imageUtil.getCode());
imageUtil.write(response.getOutputStream());
return null;
}
三、前台调用

<img id="vimg" th:src="@{code}"/>
$("#vimg").on("click",function () {
var timestamp = (new Date()).valueOf();
$(this).attr("src","code?timestamp=" + timestamp);
});