用戶登錄註冊之驗證碼技術實現
阿新 • • 發佈：2017-05-22
function 驗證碼 用戶登錄 用戶名 change
對於一些惡意強暴破解密碼的行為（即通過硬性嘗試用戶名密碼進行破解），可以采用驗證碼對其進行抵禦，對於一些程序可以識別驗證碼，則需要對驗證碼形式進行多樣化設計。
用戶登錄時設置驗證碼代碼實現：
頁面
<script type="text/javascript">
function _change() {
var imgEle = document.getElementById("img");
imgEle.src = "${pageContext.request.contextPath }/user_getVerify.action?a="
+ new Date().getTime();
}
</script>
<BODY>
<FORM id=form1 name=form1 action="${pageContext.request.contextPath }/user_login.action" method="post">
<TR>
<TD style="HEIGHT: 28px">驗證碼：</TD>
<TD style="HEIGHT: 28px">
<input type="text" name="verifyCode" size="1"/>
<img id="img" src="${pageContext.request.contextPath }/user_getVerify.action">
<br/>
<a href="javascript:_change()">換一張</a>
</TD>
<a href="#"></a>
<TD style="HEIGHT: 28px"><SPAN id=RequiredFieldValidator4
style="FONT-WEIGHT: bold; VISIBILITY: hidden; COLOR: white">請輸入驗證碼</SPAN></TD></TR>
<TR>
</FORM></BODY>2.action操作
//獲得驗證碼
public void getVerify() throws IOException{
HttpServletRequest request=ServletActionContext.getRequest();
HttpServletResponse response=ServletActionContext.getResponse();
VerifyCode vc=new VerifyCode();
BufferedImage image=vc.getImage();//獲得圖片
request.getSession().setAttribute("session_vcode",vc.getText());//將驗證碼內容放在域對象裏面
VerifyCode.output(image, response.getOutputStream());
}
public String login(){
HttpServletRequest request=ServletActionContext.getRequest();
String sessionCode = (String) request.getSession().getAttribute("session_vcode");
String paramCode = request.getParameter("verifyCode");
if(!paramCode.equalsIgnoreCase(sessionCode)){
request.setAttribute("msg", "驗證碼錯誤！");
return "login";
}
User userExit=userService.login(user);
if(userExit!=null){
if(!userExit.isState())
{
request.setAttribute("msg", "您尚未激活，請到郵箱"+userExit.getEmail()+"激活！");
return "loginerror";
}
request=ServletActionContext.getRequest();
request.getSession().setAttribute("user", userExit);
return "loginsuccess";
}else{
return "login";
}
}3.驗證碼代碼實現
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
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;
public class VerifyCode {
private int w = 70;
private int h = 35;
private Random r = new Random();
// {"宋體", "華文楷體", "黑體", "華文新魏", "華文隸書", "微軟雅黑", "楷體_GB2312"}
private String[] fontNames = {"宋體", "華文楷體", "黑體", "微軟雅黑", "楷體_GB2312"};
// 可選字符
private String codes = "23456789abcdefghjkmnopqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ";
// 背景色
private Color bgColor = new Color(255, 255, 255);
// 驗證碼上的文本
private String text ;
// 生成隨機的顏色
private Color randomColor () {
int red = r.nextInt(150);
int green = r.nextInt(150);
int blue = r.nextInt(150);
return new Color(red, green, blue);
}
// 生成隨機的字體
private Font randomFont () {
int index = r.nextInt(fontNames.length);
String fontName = fontNames[index];//生成隨機的字體名稱
int style = r.nextInt(4);//生成隨機的樣式, 0(無樣式), 1(粗體), 2(斜體), 3(粗體+斜體)
int size = r.nextInt(5) + 24; //生成隨機字號, 24 ~ 28
return new Font(fontName, style, size);
}
// 畫幹擾線
private void drawLine (BufferedImage image) {
int num = 3;//一共畫3條
Graphics2D g2 = (Graphics2D)image.getGraphics();
for(int i = 0; i < num; i++) {//生成兩個點的坐標，即4個值
int x1 = r.nextInt(w);
int y1 = r.nextInt(h);
int x2 = r.nextInt(w);
int y2 = r.nextInt(h);
g2.setStroke(new BasicStroke(1.5F));
g2.setColor(Color.BLUE); //幹擾線是藍色
g2.drawLine(x1, y1, x2, y2);//畫線
}
}
// 隨機生成一個字符
private char randomChar () {
int index = r.nextInt(codes.length());
return codes.charAt(index);
}
// 創建BufferedImage
private BufferedImage createImage () {
BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
Graphics2D g2 = (Graphics2D)image.getGraphics();
g2.setColor(this.bgColor);
g2.fillRect(0, 0, w, h);
return image;
}
// 調用這個方法得到驗證碼
public BufferedImage getImage () {
BufferedImage image = createImage();//創建圖片緩沖區
Graphics2D g2 = (Graphics2D)image.getGraphics();//得到繪制環境
StringBuilder sb = new StringBuilder();//用來裝載生成的驗證碼文本
// 向圖片中畫4個字符
for(int i = 0; i < 4; i++) {//循環四次，每次生成一個字符
String s = randomChar() + "";//隨機生成一個字母
sb.append(s); //把字母添加到sb中
float x = i * 1.0F * w / 4; //設置當前字符的x軸坐標
g2.setFont(randomFont()); //設置隨機字體
g2.setColor(randomColor()); //設置隨機顏色
g2.drawString(s, x, h-5); //畫圖
}
this.text = sb.toString(); //把生成的字符串賦給了this.text
drawLine(image); //添加幹擾線
return image;
}
// 返回驗證碼圖片上的文本
public String getText () {
return text;
}
// 保存圖片到指定的輸出流
public static void output (BufferedImage image, OutputStream out)
throws IOException {
ImageIO.write(image, "JPEG", out);
}
}4.效果
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用戶登錄註冊之驗證碼技術實現