本文实例为大家分享了Jsp+Servlet实现简单登录注册查询的具体代码，供大家参考，具体内容如下
1、注册功能：
制作一个注册页面
用户输入：
用户名
密码
年龄
注册成功：——跳转至登录页面进行登录
注册失败：——文字或其他形式的提示皆可
2、简易查询：
制作一个查询页面
输入用户名
显示该用户的用户名、密码、年龄
演示
1.启动进入登陆页面
2.点击注册，进入注册页面,成功跳转到登录页面
失败则提示
回到登录页面，登录成功进入查询页面
登录失败显示提示信息
输入用户名-显示该用户的用户名、密码、年龄
代码
dao
public class UserDao {
private Connection conn = null;
private PreparedStatement ps=null;
private int result=0;
private ResultSet rs=null;
//用户注册
public int register(User user){
String sql="insert into users(name,password,age) value (,,)";
try {
//获取数据库连接对象
conn= JDBCUtil.getConnection();
//获取数据库操作对象
ps=conn.prepareStatement(sql);
ps.setString(1,user.getName());
ps.setString(2,user.getPassword());
ps.setInt(3,user.getAge());
//执行sql
result=ps.executeUpdate();
} catch (Exception e) {
e.printStackTrace();
}finally {
JDBCUtil.close(null,ps,conn);
}
return result;
}
//登录验证用户信息
public int login(String userName,String password){
String sql ="select count(*) from users where name= and password=";
try {
conn=JDBCUtil.getConnection();
ps=conn.prepareStatement(sql);
ps.setString(1,userName);
ps.setString(2,password);
rs=ps.executeQuery();
while (rs.next()){
result=rs.getInt("count(*)");
}
} catch (Exception e) {
e.printStackTrace();
} finally {
JDBCUtil.close(rs,ps,conn);
}
return result;
}
//根据用户名 显示用户名、密码、年龄
public User findByName(String userName){
String sql="select name,password,age from users where name=";
User user = null;
try {
conn=JDBCUtil.getConnection();
ps=conn.prepareStatement(sql);
ps.setString(1,userName);
rs=ps.executeQuery();
while (rs.next()){
String name = rs.getString("name");
String password = rs.getString("password");
int age = rs.getInt("age");
user = new User(name,password,age);
}
} catch (Exception e) {
e.printStackTrace();
}finally {
JDBCUtil.close(null,ps,conn);
}
return user;
}
}
entity 实体类
public class User {
private int id;
private String name;
private String password;
private int age;
//set...
//get...
//constructor...
}
service
public class UserServiceImpl implements UserService {
UserDao userDao = new UserDao();
// 注册
@Override
public int register(User user) {
return userDao.register(user);
}
// 登陆
@Override
public int login(String userName, String password) {
return userDao.login(userName,password);
}
// 根据用户名查找信息
@Override
public User findByName(String userName) {
return userDao.findByName(userName);
}
}
servlet
// FindByNameServlet
public class FindByNameServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String name = request.getParameter("name");
UserService userService = new UserServiceImpl();
User user = userService.findByName(name);
//将查询结果放入request作用域
request.setAttribute("userInfo",user);
request.getRequestDispatcher("/jsp/index.jsp").forward(request,response);
}
}
// LoginServlet
public class LoginServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1 获取
String userName = request.getParameter("userName");
String password = request.getParameter("password");
//2 service调用dao对数据库操作
UserService userService = new UserServiceImpl();
int result = userService.login(userName, password);
//3 成功跳转到查询页面，失败跳转到失败页面
if (result0){
response.sendRedirect("/jsp/index.jsp");
}else{
response.sendRedirect("/login_error.html");
}
}
}
// RegisterServlet
public class RegisterServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
UserService userService = new UserServiceImpl();
User user = null;
int result = 0;
//1【调用请求对象】读取【请求头】参数信息，得到用户注册信息
String userName, password, age;
userName = request.getParameter("userName");
password = request.getParameter("password");
age = request.getParameter("age");
user = new User(userName, password, Integer.valueOf(age));
//2 调用userService——userDao
// 先查询用户是否存在
User byName = userService.findByName(userName);
if (byName!=null){
request.setAttribute("info","用户已存在！");
request.getRequestDispatcher("/jsp/register.jsp").forward(request,response);
}
// 注册
result = userService.register(user);
//3 设置编码格式，防止乱码
response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter();
//注册成功：——跳转至登录页面进行登录
//注册失败：——注册页面提示：注册失败
if (result == 1) {
response.sendRedirect("/login.html");
} else {
request.setAttribute("info","注册失败！");
request.getRequestDispatcher("/jsp/register.jsp").forward(request,response);
}
}
}
JDBCUtil
public class JDBCUtil {
private JDBCUtil(){}
//静态代码块在类加载时执行，并且执行一次。
static{
try {
Class.forName("com.mysql.cj.jdbc.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
//获取数据库连接对象
public static Connection getConnection() throws Exception{
String url="jdbc:mysql://127.0.0.1:3306/zyuseSSL=falseserverTimezone=UTCrewriteBatchedStatements=true";
String user="root";
String password="rootroot";
return DriverManager.getConnection(url,user,password);
}
/**
*关闭资源
* @param conn 连接对象
* @param ps 数据库操作对象
* @param rs 结果集
*/
public static void close(ResultSet rs, Statement ps, Connection conn){
if (rs != null) {
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (ps != null) {
try {
ps.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (conn != null) {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
index.jsp
%@ page import="entity.User" %
%@ page contentType="text/html;charset=UTF-8" language="java" %
html
head
title查询页面/title
/head
body
div align="center"
h2/输入用户名，查询信息
form action="/findByName" method="get"
input type="text" name="name" id="name"
input type="submit" value="查询"
/form
%
User userInfo = (User) request.getAttribute("userInfo");
%
%
if (userInfo != null) {
%
table border="3"
tr
th用户名/th
th密码/th
th年龄/th
/tr
tr
td nbsp; nbsp; %=userInfo.getName()% nbsp; nbsp;/td
td nbsp; nbsp; %=userInfo.getPassword()% nbsp; nbsp;/td
td nbsp; nbsp; %=userInfo.getAge()% nbsp; nbsp;/td
/tr
/table
%
}
%
/div
/body
/html
register.jsp
%@ page import="com.mysql.cj.util.StringUtils" %
%@ page contentType="text/html;charset=UTF-8" language="java" %
html
head
titleTitle/title
/head
body
br
br
%
String info =(String) request.getAttribute("info");
%
%
if (!StringUtils.isNullOrEmpty(info)){
%
h1 style="color: red;text-align: center" %=info%/h1
%
}
%
div align="center"
form action="/register" method="post"
table border="2"
tr
th用户名/th
tdinput type="text" name="userName"//td
/tr
tr
th密码/th
tdinput type="password" name="password"//td
/tr
tr
th年龄/th
tdinput type="text" name="age"//td
/tr
tr
td colspan="2" align="center"
input type="submit" value="注册"/
input type="reset" value="清空"/
/td
/tr
/table
/form
/div
/body
/html
web.xml
xml version="1.0" encoding="UTF-8" web-app xmlns="http://xmlns.*j*c*p.org/xml/ns/javaee" xmlns:xsi="http://www.**w*3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.*j*c*p.org/xml/ns/javaee http://xmlns.*j*c*p.org/xml/ns/javaee/web-app_4_0.xsd" version="4.0" servlet servlet-nameLoginServlet/servlet-name servlet-classservlet.LoginServlet/servlet-class /servlet servlet servlet-nameRegisterServlet/servlet-name servlet-classservlet.RegisterServlet/servlet-class /servlet servlet servlet-nameFindByNameServlet/servlet-name servlet-classservlet.FindByNameServlet/servlet-class /servlet servlet-mapping servlet-nameLoginServlet/servlet-name url-pattern/login/url-pattern /servlet-mapping servlet-mapping servlet-nameRegisterServlet/servlet-name url-pattern/register/url-pattern /servlet-mapping servlet-mapping servlet-nameFindByNameServlet/servlet-name url-pattern/findByName/url-pattern /servlet-mapping !--设置默认欢迎文件规则-- welcome-file-list welcome-filelogin.html/welcome-file !--servlet 作为默认欢迎文件 ‘/'需要去掉-- /welcome-file-list /web-app
login.html
!DOCTYPE html html lang="en" head meta charset="UTF-8" title登陆界面/title /head body div align="center" font size="10px" color="#00008b"用户登录/font form action="/login" method="post" table border="2" tr th用户名/th tdinput type="text" name="userName"//td /tr tr th密码/th tdinput type="password" name="password"//td /tr tr td colspan="2" align="center" input type="submit" value="登录"/ input type="reset" / /td /tr /table /form a href="/jsp/register.jsp" style="text-align: left"立即注册/a /div /body /html
login_error.html
!DOCTYPE html html lang="en" head meta charset="UTF-8" title登录验证/title /head body div align="center" font size="10px" color="#00008b"用户登录/fontbr font size="5px" color="red"登录信息不存在，请重新登陆！！！/font form action="/login" method="post" table border="2" tr th用户名/th tdinput type="text" name="userName" //td /tr tr th密码/th tdinput type="password" name="password" //td /tr tr td colspan="2" align="center" input type="submit" value="登录"/ input type="reset" /td /tr /table /form a href="/jsp/register.jsp" style="text-align: left"立即注册/a /div /body /html