This article shares two examples for you, I believe you will like it.
Example 1: Randomly generate verification code pictures and output them as a png file
Reproduction image:
import java.awt.Color;import java.awt.Font;import java.awt.Graphics;import java.awt.image.BufferedImage;import java.io.File;import java.io.IOException;import java.util.Random; import javax.imageio.ImageIO; public class Mytest10 { public static Random random = new Random(); public static int r(int min,int max){ int num=0; num=random.nextInt(max-min)+min; return num; } public static void main(String[] args) throws IOException { // TODO Auto-generated method stub //Create a picture int w=120; int h=50; BufferedImage img = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB); //Draw a rectangle on the picture as background Graphics g = img.getGraphics(); g.setColor(new Color(r(50,250),r(50,250),r(50,250))); g.fillRect(0, 0, w, h); String str = "aqzxswedcfrvgtbhyujklp23456789"; for(int i=0;i<4;i++){ g.setColor(new Color(r(50,180),r(50,180),r(50,180))); g.setFont(new Font("Bold",Font.PLAIN,40)); char c = str.charAt(r(0,str.length())); g.drawString(String.valueOf(c), 10+i*30, r(h-30,h)); } //Draw a random line for(int i=0;i<25;i++){ g.setColor(new Color(r(50,180),r(50,180),r(50,180))); g.drawLine(r(0,w),r(0,h),r(0,w),r(0,h)); } //Output the images created in memory to the file File file =new File("vcode.png"); ImageIO.write(img, "png", file); System.out.println("Image output completed"); } } Example 2: Java randomly generates commonly used Chinese character verification codes
import java.awt.Color;import java.awt.Font;import java.awt.Graphics;import java.awt.Graphics2D;import java.awt.image.BufferedImage;import java.io.IOException;import java.util.Random;import javax.imageio.ImageIO;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;/*** Generate random Chinese characters***/public class DrawImage extends HttpServlet {public static final int WIDTH = 120;public static final int HEIGHT = 30;public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {this.doPost(request, response);}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {request.setCharacterEncoding("utf-8");response.setContentType("text/html;charset=utf-8");// Create cache BufferedImage bi = new BufferedImage(WIDTH, HEIGHT,BufferedImage.TYPE_INT_RGB);// Get canvas Graphics g = bi.getGraphics();// Set the back color setBackGround(g);// Set the border setBorder(g);// Draw the interference line drawRandomLine(g);// Write the random number String random = drawRandomNum((Graphics2D) g);// Store the random Chinese characters in the session request.getSession().setAttribute("checkcode", random);// Write the graphics to the browser response.setContentType("image/jpeg");// Hair control browser does not cache response.setDateHeader("expries", -1);response.setHeader("Cache-Control", "no-cache");response.setHeader("Pragma", "no-cache");// Write the image to the browser ImageIO.write(bi, "jpg", response.getOutputStream());}/*** Set background color** @param g*/private void setBackGround(Graphics g) {// Set color g.setColor(Color.WHITE);// Fill the area g.fillRect(0, 0, WIDTH, HEIGHT);}/*** Set border** @param g*/private void setBorder(Graphics g) {// Set the border color g.setColor(Color.BLUE);// Border area g.drawRect(1, 1, WIDTH - 2, HEIGHT - 2);}/*** Draw random lines** @param g*/private void drawRandomLine(Graphics g) {// Set color g.setColor(Color.GREEN);// Set the number of lines and draw lines for (int i = 0; i < 5; i++) {int x1 = new Random().nextInt(WIDTH);int y1 = new Random().nextInt(HEIGHT);int x2 = new Random().nextInt(WIDTH);int y2 = new Random().nextInt(HEIGHT);g.drawLine(x1, y1, x2, y2);}}/*** Draw random Chinese characters** @param g* @return*/private String drawRandomNum(Graphics2D g) {StringBuffer sb = new StringBuffer();// Set color g.setColor(Color.RED);// Set font g.setFont(new Font("宋体", Font.BOLD, 20));// Prepare the commonly used Chinese characters set String base = "/u7684/u4e00/u4e86/u662f/u6211/u4e0d/u5728/u4eba/u4eec/u6709/u6765/u4ed6/u8fd9/u4e0a/u7740/u4e2a/u5730/u5230/u5927/u91cc/u8bf4/u5c31/u53bb/u5b50/u5f97/u4e5f/u548c/u90a3/u8981/u4e0b/uu 770b/u5929/u65f6/u8fc7/u51fa/u5c0f/u4e48/u8d77/u4f60/u90fd/u628a/u597d/u8fd8/u591a/u6ca1/u4e3a/u53c8/u53ef/u5bb6/u5b66/u53ea/u4ee5/u4e3b/u4f1a/u6837/u5e74/u60f3/u751f/u540c/u8001/u4e2 d/u5341/u4ece/u81ea/u9762/u524d/u5934/u9053/u5b83/u540e/u7136/u8d70/u5f88/u50cf/u89c1/u4e24/u7528/u5979/u56fd/u52a8/u8fdb/u6210/u56de/u4ec0/u8fb9/u4f5c/u5bf9/u5f00/u800c/u5df1/u4e9b/uu4e9b/uu4f5c/u5f00/u800c/u5df1/u4e9b/uu 73b0/u5c71/u6c11/u5019/u7ecf/u53d1/u5de5/u5411/u4e8b/u547d/u7ed9/u957f/u6c34/u51e0/u4e49/u4e09/u58f0/u4e8e/u9ad8/u624b/u77e5/u7406/u773c/u5fd7/u70b9/u5fc3/u6218/u4e8c/u95ee/u4f46/u8ea b/u65b9/u5b9e/u5403/u505a/u53eb/u5f53/u4f4f/u542c/u9769/u6253/u5462/u771f/u5168/u624d/u56db/u5df2/u6240/u654c/u4e4b/u6700/u5149/u4ea7/u60c5/u8def/u5206/u603b/u6761/u767d/u8bdd/u4e1c/uu4e1c/uu4ea7/u60c5/u8def/u5206/u603b/u6761/u767d/u8bdd/u4e1c/uu4e1c/u 5e2d/u6b21/u4eb2/u5982/u88ab/u82b1/u53e3/u653e/u513f/u5e38/u6c14/u4e94/u7b2c/u4f7f/u5199/u519b/u5427/u6587/u8fd0/u518d/u679c/u600e/u5b9a/u8bb8/u5feb/u660e/u884c/u56e0/u522b/u98de/u591 6/u6811/u7269/u6d3b/u90e8/u95e8/u65e0/u5f80/u8239/u671b/u65b0/u5e26/u961f/u5148/u529b/u5b8c/u5374/u7ad9/u4ee3/u5458/u673a/u66f4/u4e5d/u60a8/u6bcf/u98ce/u7ea7/u8ddf/u7b11/u554a/u5b69/u 4e07/u5c11/u76f4/u610f/u591c/u6bd4/u9636/u8fde/u8f66/u91cd/u4fbf/u6597/u9a6c/u54ea/u5316/u592a/u6307/u53d8/u793e/u4f3c/u58eb/u8005/u5e72/u77f3/u6ee1/u65e5/u51b3/u767e/u539f/u62ff/u7fa 4/u7a76/u5404/u516d/u672c/u601d/u89e3/u7acb/u6cb3/u6751/u516b/u96be/u65e9/u8bba/u5417/u6839/u5171/u8ba9/u76f8/u7814/u4eca/u5176/u4e66/u5750/u63a5/u5e94/u5173/u4fe1/u89c9/u6b65/u53cd/u 5904/u8bb0/u5c06/u5343/u627e/u4e89/u9886/u6216/u5e08/u7ed3/u5757/u8dd1/u8c01/u8349/u8d8a/u5b57/u52a0/u811a/u7d27/u7231/u7b49/u4e60/u9635/u6015/u6708/u9752/u534a/u706b/u6cd5/u9898/u5ef a/u8d76/u4f4d/u5531/u6d77/u4e03/u5973/u4efb/u4ef6/u611f/u51c6/u5f20/u56e2/u5c4b/u79bb/u8272/u8138/u7247/u79d1/u5012/u775b/u5229/u4e16/u521a/u4e14/u7531/u9001/u5207/u661f/u5bfc/u665a/uu4e14/u7531/u9001/u5207/u661f/u5bfc/u665a/uu 8868/u591f/u6574/u8ba4/u54cd/u96ea/u6d41/u672a/u573a/u8be5/u5e76/u5e95/u6df1/u523b/u5e73/u4f1f/u5fd9/u63d0/u786e/u8fd1/u4eae/u8f7b/u8bb2/u519c/u53e4/u9ed1/u544a/u754c/u62c9/u540d/u544 0/u571f/u6e05/u9633/u7167/u529e/u53f2/u6539/u5386/u8f6c/u753b/u9020/u5634/u6b64/u6cbb/u5317/u5fc5/u670d/u96e8/u7a7f/u5185/u8bc6/u9a8c/u4f20/u4e1a/u83dc/u722c/u7761/u5174/u5f62/u91cf/uu 54b1/u89c2/u82e6/u4f53/u4f17/u901a/u51b2/u5408/u7834/u53cb/u5ea6/u672f/u996d/u516c/u65c1/u623f/u6781/u5357/u67aa/u8bfb/u6c99/u5c81/u7ebf/u91ce/u575a/u7a7a/u6536/u7b97/u81f3/u653f/u57c e/u52b3/u843d/u94b1/u7279/u56f4/u5f1f/u80dc/u6559/u70ed/u5c55/u5305/u6b4c/u7c7b/u6e10/u5f3a/u6570/u4e61/u547c/u6027/u97f3/u7b54/u54e5/u9645/u65e7/u795e/u5ea7/u7ae0/u5e2e/u5566/u53d7/uu5ea7/u7ae0/u5e2e/u5566/u53d7/uu 7cfb/u4ee4/u8df3/u975e/u4f55/u725b/u53d6/u5165/u5cb8/u6562/u6389/u5ffd/u79cd/u88c5/u9876/u6025/u6797/u505c/u606f/u53e5/u533a/u8863/u822c/u62a5/u53f6/u538b/u6162/u53d4/u80cc/u7ec6";int x = 5;// Control word count for (int i = 0; i < 4; i++) {// Set the font rotation angle int degree = new Random().nextInt() % 30;// Intercept Chinese characters String ch = base.charAt(new Random().nextInt(base.length())) + "";sb.append(ch);// Forward angle g.rotate(degree * Math.PI / 180, x, 20);g.drawString(ch, x, 20);// Reverse angle g.rotate(-degree * Math.PI / 180, x, 20);x += 30;}return sb.toString();}}The above are the relevant codes for Java generating image verification codes and Chinese character verification codes. I hope it will be helpful to everyone's learning.