做web开发，登录验证是免不了的，今天学习了servlet的登录验证，当然是很简单的，没有使用session，request等作用域对象，所以还是可以直接通过地址访问网页的。
login.java:
package com.ncu;
import java.io.PrintWriter;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class login extends HttpServlet{
public void doGet(HttpServletRequest req,HttpServletResponse res){
try{
//res.setCharacterEncoding("utf-8");
res.setContentType("text/html;charset=gbk");
PrintWriter pw=res.getWriter();
//返回登录界面
pw.print("<html>");
pw.print("<head>");
pw.print("<title>登录界面</title></head>");
pw.print("<body>");
pw.print("<h1>用户登录界面</h1>");
pw.print("<form action='loginpro' method=post>");
pw.print("用户名：<input type=text name=userName><br>");
pw.print("密码：<input type=password name=Pwd><br>");
pw.print("<input type=submit value=submit>");
pw.print("</body></html>");
}catch(Exception e)
{
e.printStackTrace();
}
}
}
LoginPro.java:
package com.ncu;
import java.io.PrintWriter;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class LoginPro extends HttpServlet{
public void doPost(HttpServletRequest req,HttpServletResponse res){
try{
String user=req.getParameter("userName");
String pwd=req.getParameter("Pwd");
if(user==null){
user="";
}
if(pwd==null)
{
pwd="";
}
if(user.equals("nicolas")&&pwd.equals("nicolas")){
//用户和密码合法
//res.sendRedirect("wel");
// res.setCharacterEncoding("gbk");
// PrintWriter pw=res.getWriter();
// pw.print("恭喜你，登录成功！！");
res.sendRedirect("welcome");
}
else{
//不合法进行跳转
res.sendRedirect("login");//跳转到登录界面
}
}catch(Exception e)
{
e.printStackTrace();
}
}
}
Welcome.java:
package com.ncu;
import java.io.PrintWriter;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class Welcome extends HttpServlet{
public void doGet(HttpServletRequest req,HttpServletResponse res){
try{
res.setCharacterEncoding("gbk");
PrintWriter pw=res.getWriter();
pw.print("welcome，您好");
}catch(Exception e)
{
e.printStackTrace();
}
}
}
servletDemo工程代码下载地址：
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
<display-name></display-name>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<servlet>
<!-- 给你的servlet取名，任意的 -->
<servlet-name>hello</servlet-name>
<!-- 指明servlet的路径（包名+类名 -->
<servlet-class>com.ncu.Hello</servlet-class>
</servlet>
<servlet-mapping>
<!-- 这个servlet名必须和映射的一致 -->
<servlet-name>hello</servlet-name>
<!-- 这是在浏览器中输入的访问该servlet的url -->
<url-pattern>/nicolas</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>helloservlet</servlet-name>
<servlet-class>com.ncu.HelloServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>helloservlet</servlet-name>
<url-pattern>/helloservlet</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>helloHttpServlet</servlet-name>
<servlet-class>com.ncu.helloHttpServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>helloHttpServlet</servlet-name>
<url-pattern>/helloHttpServlet</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>login</servlet-name>
<servlet-class>com.ncu.login</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>login</servlet-name>
<url-pattern>/login</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>loginpro</servlet-name>
<servlet-class>com.ncu.LoginPro</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>loginpro</servlet-name>
<url-pattern>/loginpro</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>welcome</servlet-name>
<servlet-class>com.ncu.Welcome</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>welcome</servlet-name>
<url-pattern>/welcome</url-pattern>
</servlet-mapping>
</web-app>
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