随机生成验证码页面显示

package cn.lw.checking;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/*
 * 创建图片
 */
public class ServletDemo extends HttpServlet{
 public void doGet(HttpServletRequest res,HttpServletResponse req){
  //创建一张内存中的图片,
  BufferedImage bi = new BufferedImage(70, 35, BufferedImage.TYPE_INT_RGB);
  //获取当前图片画笔
  Graphics g = bi.getGraphics();
  //设置图片背景色
  g.setColor(new Color(240,240,240));
  //填充图片
  g.fillRect(0, 0, 70,35);
  //设置颜色
  g.setColor(Color.RED);
  //干扰线
  g.drawLine(5, 5, 70-5, 35-5);
  //设置字体
  g.setFont(new Font("华文行楷", Font.BOLD, 26));
  //写入数据
  g.drawString("hello",0,30);
  //保存图片
  try {
   ImageIO.write(bi, "JEG", req.getOutputStream());
  } catch (IOException e) {
   e.printStackTrace();
  }
 }

}

package cn.lw.checking;

import java.awt.image.BufferedImage;
import java.io.IOException;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ServletDemo1 extends HttpServlet {
 public void doGet(HttpServletRequest res,HttpServletResponse rep){
  VCode vc = new VCode();
  BufferedImage img = vc.getImage();
  System.out.println(vc.getCode());
  try {
   VCode.saveImage(img, rep.getOutputStream());
  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
 }
}

package cn.lw.checking;

import java.awt.BasicStroke;
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.io.OutputStream;
import java.util.Random;

import javax.imageio.ImageIO;

/*
 * 设置图片.随机生成,验证码
 */
public class VCode {
 private int w = 70;// 宽
 private int h = 35;// 高
 private Color bgColor = new Color(240, 240, 240); // 背景色
 private Random random = new Random(); // 随机数
 private StringBuffer code = new StringBuffer(4);// 存放4个字符

 /*
  * 1.创建图片 2.创建背景色
  */
 private BufferedImage createImage() {
  // 创建图片
  BufferedImage img = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
  // 设置笔画颜色
  img.getGraphics().setColor(bgColor);
  // 重填一个与图形一样大小的矩形,设置背景色.
  img.getGraphics().fillRect(0, 0, w, h);
  return img;
 }

 /*
  * 生成随机颜色
  */
 private Color randomColor() {
  int r = random.nextInt(256);
  int g = random.nextInt(256);
  int b = random.nextInt(256);
  return new Color(r, g, b);
 }

 /*
  * 字体名,样式,字号.
  */
 // 字体
 private String[] fontName = { "宋体", "华文楷体", "黑体", "华文新魏", "华文隶书", "微软雅黑",
   "楷体_GB2312" };
 // 字号规范
 private int[] fontSize = { 24, 25, 26, 27, 28 };

 /*
  * 随机生成字体
  */
 private Font randomFont() {
  // 如果数组长度为7，数值为0~6;
  int index = random.nextInt(fontName.length);
  String name = fontName[index];

  int style = random.nextInt(4);
  index = random.nextInt(fontSize.length);

  // 随机生成fontSize下标
  int size = fontSize[index];

  return new Font(name, style, size);
 }

 // 生成大写字母小写字母A~Z 数字0~9;
 private String codes = "abcdefghigklmnopqrstuvwxyzABCDEFGHILKLMNOPQRSTUVWXYZ0123456789";

 // 随机生成字符
 private String randomChar() {
  int index = random.nextInt(codes.length());
  return codes.charAt(index) + "";
 }

 private void drawLine(BufferedImage img) {
  Graphics2D g = (Graphics2D) img.getGraphics();
  g.setColor(Color.BLACK);
  g.setStroke(new BasicStroke(1.5F));
  for (int i = 0; i < 5; i++) {
   int x1 = random.nextInt(w);
   int y1 = random.nextInt(h);
   int x2 = random.nextInt(w);
   int y2 = random.nextInt(h);
   g.drawLine(x1, y1, x2, y2);
  }
 }

 // 用户调用这个方法获取图片
 public BufferedImage getImage() {

  BufferedImage im = createImage();
  Graphics g = im.getGraphics();
  for (int i = 0; i < 4; i++) {
   String ch = this.randomChar();// 获取随机字符
   code.append(ch);// 记录下来生成的字符
   g.setColor(this.randomColor());// 随机颜色
   g.setFont(this.randomFont());// 随机字体
   g.drawString(ch, w / 4 * i, h - 5);
  }
  this.drawLine(im);// 添加干扰线
  return im;

 }

 // 这个方法必须在getImage()方法之后调用！
 public String getCode() {
  return code.toString();
 }

 // 保存图片
 public static void saveImage(BufferedImage img, OutputStream out)
   throws IOException {
  ImageIO.write(img, "JPEG", out);
 }
}

 

package cn.lw.junit;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

import javax.imageio.ImageIO;

import org.junit.Test;

import cn.lw.checking.VCode;

public class Text {
 public void fun1() throws Exception, IOException{
  //创建一张内存中的图片
  BufferedImage img = new BufferedImage(70,35,BufferedImage.TYPE_INT_RGB);
  //获取当前图片的笔画
  Graphics g = img.getGraphics();
  g.setColor(new Color(240,240,240));
  g.fillRect(0, 0, 70, 35);
  
  g.setColor(Color.RED);
  g.drawLine(5, 5, 70-5, 35-5);
  g.setFont(new Font("华文行楷", Font.BOLD, 26));
  g.drawString("hello", 0, 30);
  // 保存图片
  ImageIO.write(img, "JPEG", new FileOutputStream("F:\\a.jpg"));
 }
 @Test
 public void fun2() throws FileNotFoundException, IOException {
  VCode v = new VCode();
  BufferedImage img = v.getImage();
  VCode.saveImage(img, new FileOutputStream("F:\\a.jpg"));
 }
}

jsp 部分

 

</head>
 
  <body>
    This is my JSP page. <br>
    验证码:
    <input type="text" name="vcode" size="3"/>&nbsp;
    <img id=vc src="checking/ServletDemo1" border="2"/>
    <a href="javascript:_chage()">看不清换一张</a>
    <script type="text/javascript">
     function _chage(){
     var img = document.getElementById("vc");
     img.src = "/checking/ServletDemo1?a=" + new Date().getTime();
     }
    </script>
    <br/>
    <input type="submit" value="提交"/>
  </boday>