Java语言初学者的练手小任务，宠物管理系统

package com.test; import javax.imageio.ImageIO; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.awt.*; import java.awt.image.BufferedImage; import java.io.IOException; import java.util.Random; @WebServlet("/generate") public class Generate extends HttpServlet { //图片宽和高 private static final int WEIGHT=120; private static final int HEIGHT=30; @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { this.doPost(req,resp); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { //1、在内存中生成一张图片 BufferedImage bufferedImage = new BufferedImage(WEIGHT,HEIGHT,BufferedImage.TYPE_INT_RGB); //2、获取内存中的图片 Graphics2D graphics = (Graphics2D) bufferedImage.getGraphics(); //3、设置图片的背景 setBackground(graphics); //4、设置图片边框 setBorder(graphics); //5、设置验证码的干扰线 setRandomLine(graphics); //6、生成验证码的内容 String randomString=getRandomString(graphics,"mixed"); //7、将验证码保存到session中 req.getSession().setAttribute("validate_session",randomString); //8、设置浏览器以图片的方式接收验证码 resp.setContentType("image/jpg"); //9、将验证码图片返回给浏览器 ImageIO.write(bufferedImage,"jpg",resp.getOutputStream()); } private String getRandomString(Graphics2D graphics, String type) { //设置验证码的颜色 graphics.setColor(Color.darkGray); //设置验证码字体 graphics.setFont(new Font("宋体",Font.BOLD,20)); String number="0123456789"; String character="ABCDEFGHIJKLMNOPQRSTOVWXYZ"; String mixed="0123456789ABCDEFGHIJKLMNOPQRSTOVWXYZ"; String randomString = null; if("number".equals(type)){ randomString=generate(graphics,number); }else if("character".equals(type)){ randomString=generate(graphics,character); }else if("mixed".equals(type)){ randomString=generate(graphics,mixed); } return randomString; } private String generate(Graphics2D graphics,String type) { StringBuilder stringBuilder=new StringBuilder();//用于存放验证码内容 int x=5;//设置验证码字符旋转初始角度 String ch=null;//用于存储每一个验证码字符 for (int i = 0; i < 4; i++) { int degree=new Random().nextInt()%30; //获取验证码字符 ch=String.valueOf(type.charAt(new Random().nextInt(type.length())));//获取验证码第一个字符 stringBuilder.append(ch); //设置验证码字符正向旋转角度 graphics.rotate(degree*Math.PI/180,x,20); graphics.drawString(ch,x,20); //反向选择 graphics.rotate(-degree*Math.PI/180,x,20); x+=20; } return stringBuilder.toString(); } private void setRandomLine(Graphics graphics) { //设置干扰线的颜色 graphics.setColor(Color.darkGray); //画干扰线 for (int i = 0; i < 5; i++) { int x1=new Random().nextInt(WEIGHT); int y1=new Random().nextInt(HEIGHT); int x2=new Random().nextInt(WEIGHT); int y2=new Random().nextInt(HEIGHT); graphics.drawLine(x1,y1,x2,y2); } } private void setBorder(Graphics graphics) { //设置边框颜色 graphics.setColor(Color.gray); graphics.drawRect(1,1,WEIGHT-2,HEIGHT-2); } private void setBackground(Graphics graphics) { graphics.setColor(Color.gray); graphics.fillRect(0,0,WEIGHT,HEIGHT); } }