jsp界面：
<body>
<h1>登錄</h1>
<form action="/day11_1/LoginServlet" method="post">
用戶名：<input type="text" name="username"/></br>
密 碼：<input type="password" name="password"/></br>
驗證碼：<input type="text" name="verifyCode" size="3"/>
<img src="/day11_1/VerifyCodeServlet" id="vc" >
<a href="javascript:change()">換一張</a>
</br>
<input type="submit" value="登錄"/>
</form>
</body>
<script type="text/javascript">
function change(){
var imgEle=document.getElementById("vc");
imgEle.src="/day11_1/VerifyCodeServlet?"+new Date().getTime();
}
</script>
</html>生成驗證碼的Servlet,需要導入生成驗證碼的的 jar包
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import cn.itcast.vcode.utils.VerifyCode;
public class VerifyCodeServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
VerifyCode vc = new VerifyCode();
BufferedImage image = vc.getImage();
String text=vc.getText();
request.getSession().setAttribute("session_vcode", text);
VerifyCode.output(image, response.getOutputStream());
}
}
處理驗證碼是否正確的Servlet
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class LoginServlet extends HttpServlet {
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
String vc = request.getParameter("verifyCode");
String sessionVc= (String)request.getSession().getAttribute("session_vcode");
if(sessionVc.equalsIgnoreCase(vc)){
response.getWriter().print("ok");
}
else{
response.getWriter().print("錯了");
}
}
}