拿到信息必须进行非空验证
用servlet做注册登陆时，在form表单的action中不用加后缀.java,jsp文件需要加
public boolean CheckParm(String...args){
for(String s:args){
if("".equals(s)||s==null){
return false;
}
}
return true;
}
当不确定传入的参数个数是可以用String...args，表示多参数传入
有返回值类型的方法一定加return
在servlet里面执行的代码写在doget方法中
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
response.setContentType("text/html; charset=utf-8");
防止输出出现乱码的代码表示
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="TextServlet" method="post">
<input type="text" name="username" placeholder="请输入用户名"/><br>
<input type="text" name="password" placeholder="请输入密码"/><br>
<input type="text" name="password1" placeholder="请再次输入密码"/><br>
<input type="text" name="realname" placeholder="请输入真实名字"/><br>
<input type="submit" value="提交"/>
<a href="login.jsp"> 超级链接</a>
</form>
</body>
</html>
注册的servlet类
package com.hanqi.textservlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class TextServlet
*/
@WebServlet("/TextServlet")
public class TextServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public TextServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
response.setContentType("text/html; charset=utf-8");
String username = request.getParameter("username");
String password = request.getParameter("password");
String password1 = request.getParameter("password1");
String realname = request.getParameter("realname");
response.getWriter().append("username:"+username+"password:"+password+"realname:"+realname);
if(CheckParm(username,password,password1)){
if(password.equals(password1)){
Object obj=request.getServletContext().getAttribute(username);
if(obj==null){
request.getServletContext().setAttribute(username, username);
request.getServletContext().setAttribute(password, password);
response.sendRedirect("message.jsp?code=1");
}else{
response.sendRedirect("message.jsp?code=4");
}
}else{
response.sendRedirect("message.jsp?code=3");
}
}else{
response.sendRedirect("message.jsp?code=2");
}
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
public boolean CheckParm(String...args){
for(String s:args){
if("".equals(s)||s==null){
return false;
}
}
return true;
}
}
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="LoginServlet" method="post">
<input type="text" name="username" placeholder="请输入用户名"/><br>
<input type="text" name="password" placeholder="请输入密码"/><br>
<input type="submit" value="登陆"/>
</form>
</body>
</html>
登陆的servlet类
package com.hanqi.textservlet;
import java.io.IOException;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class LoginServlet
*/
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public LoginServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
response.setContentType("text/html; charset=utf-8");
String username=request.getParameter("username");
String password=request.getParameter("password");
ServletContext application=request.getServletContext();
Object obj=application.getAttribute(username);
Object ob=application.getAttribute(password);
if(obj!=null){
String user=(String)obj;
if(username.equals(user)){
if(password.equals(ob)){
response.sendRedirect("index.jsp");
}else{response.sendRedirect("message.jsp?code=7");}
}else{
response.sendRedirect("message.jsp?code=5");
}
}else{
response.sendRedirect("message.jsp?code=6");
}
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
未按要求输入的提示页面的实现
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<%
String code=request.getParameter("code");
if("1".equals(code)){
out.print("<h1>注册成功！</h1>");
}if("2".equals(code)){
out.print("<h1>信息输入不完整！</h1>");
}if("3".equals(code)){
out.print("<h1>输入的密码不一致！</h1>");
}if("4".equals(code)){
out.print("<h1>用户已经存在！</h1>");
}if("5".equals(code)){
out.print("<h1>用户名错误！</h1>");
}if("6".equals(code)){
out.print("<h1>用户不存在！</h1>");
}if("7".equals(code)){
out.print("<h1>密码错误！</h1>");
}
%>
</body>
</html>
时间： 2024-08-02 11:04:43