java jsp+servlet實現登入網頁設計
阿新 • • 發佈：2018-12-31
這次涉及到四個檔案:
登入頁面:login.jsp 登入成功歡迎頁面:success.jsp
登入失敗頁面:fail.jsp
Servlet處理檔案:LoginServlet.java 其實還涉及到一個檔案:web.xml,這個後面再說: 下面分別介紹這幾個檔案:
//--------------------------------------------------------------------------------------------------------------------
LoginServlet.java 內容： package org.cai.servlet ; import java.sql.* ;
import java.io.* ;
import javax.servlet.http.* ;
import javax.servlet.* ; public class LoginServlet extends HttpServlet implements Servlet{
public LoginServlet(){
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
}
// protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
// System.out.println("-------------------------") ;
// doPost(request, response) ;
// }
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
response.setContentType("text/html;charset=gb2312") ;
request.setCharacterEncoding("gb2312") ;
String result = "" ;
//獲取使用者名稱
String username = request.getParameter("username") ;
String psw = request.getParameter("password") ;
if ((username == "") || (username==null) || (username.length() > 20 )){
try{
result = "請輸入使用者名稱(不能超過20個字元)!" ;
request.setAttribute("message" ,result) ;
response.sendRedirect("login.jsp") ;
}catch(Exception e){
e.printStackTrace() ;
}
} if ((psw == "") || (psw==null) || (psw.length() > 20 )){
try{
result = "請輸入密碼(不能超過20個字元)!" ;
request.setAttribute("message" ,result) ;
response.sendRedirect("login.jsp") ;
}catch(Exception e){
e.printStackTrace() ;
}
}
//登記JDBC驅動程式
try{
Class.forName("org.gjt.mm.mysql.Driver") ;
}catch(ClassNotFoundException e){
e.printStackTrace() ;
System.out.println("Class Not Found Exception . ") ;
}
//連線URL
String url ="jdbc:mysql://localhost:3306/learnJSP" ;
Connection conn = null ;
Statement stmt = null ;
ResultSet rs = null ;
try{
conn = DriverManager.getConnection(url, "root", "root") ;
stmt = conn.createStatement() ;
//SQL語句
String sql ="select * from userInfo where username='"+username+"' and userpsw= '"+psw+"'" ;
rs = stmt.executeQuery(sql) ;//返回查詢結果
}catch(SQLException e){
e.printStackTrace() ;
}
HttpSession session = request.getSession() ;
session.setAttribute("username", username) ;
//System.out.println("+++++++++++++++++++++++"+ username) ;
try{
if (rs.next()){ //如果記錄集非空，表明有匹配的使用者名稱和密碼，登陸成功
// 登入成功後將username設定為session變數的username
// 這樣在後面就可以通過 session.getAttribute("username") 來獲取使用者名稱，
// 同時這樣還可以作為使用者登入與否的判斷依據
session.setAttribute("age",rs.getString("age")) ;
session.setAttribute("sex",rs.getString("sex")) ;
session.setAttribute("weight",rs.getString("weight")) ;
response.sendRedirect("success.jsp") ;
}else{
session.setAttribute("message", "使用者名稱或密碼不匹配。");
response.sendRedirect("fail.jsp") ;
}
}catch(SQLException e){
e.printStackTrace() ;
}
}
private static final long serialVersionUID = 1L; } //--------------------------------------------------------------------------------------------------------------------
login.jsp內容：
<%@ page language="java" contentType="text/html;charset=gb2312"%> <html>
<head>
<title>登陸</title>
</head>
<body>
<form method="POST" name="frmLogin" action="LoginServlet">
<h1 align="center">使用者登入</h1><br />
<center>
<table border=1>
<tr>
<td>使用者名稱：</td>
<td>
<input type="text" name="username" value="Your name" size="20" maxlength="20" onfocus="if (this.value=='Your name') this.value='';" />
</td>
</tr>
<tr>
<td>密 碼：</td>
<td>
<input type="password" name="password" value="Your password" size="20" maxlength="20" onfocus="if (this.value=='Your password') this.value='';" />
</td>
</tr>
<tr>
<td>
<input type="submit" name="Submit" value="提交" onClick="return validateLogin()" />
</td>
<td>
<input type="reset" name="Reset" value="重置" />
</td>
</tr>
</table>
</center>
</form>
<script language="javascript">
function validateLogin(){
var sUserName = document.frmLogin.username.value ;
var sPassword = document.frmLogin.password.value ;
if ((sUserName =="") || (sUserName=="Your name")){
alert("請輸入使用者名稱!");
return false ;
}
if ((sPassword =="") || (sPassword=="Your password")){
alert("請輸入密碼!");
return false ;
}
}
</script>
</body>
</html>
//--------------------------------------------------------------------------------------------------------------------
success.jsp 內容；
<%@ page language="java" contentType="text/html;charset=gb2312" pageEncoding ="gb2312"%>
<html>
<head>
<title>歡迎</title>
</head>
<body>
<%
String userName = (String)session.getAttribute("username") ;
String age = (String)session.getAttribute("age") ;
String weight = (String)session.getAttribute("weight") ;
String sex = (String)session.getAttribute("sex") ; System.out.println("性別：A" + sex +"A") ;
if (sex.trim().equals("M")) {
sex ="男" ;
}else{
sex = "女" ;
}
%>
<div align="center">
<%=userName %>
歡迎您，登陸成功！<br />
<font color="blue">登陸使用者資訊：</font>
<table border =1 >
<tr>
<td> 姓名： </td>
<td> <%=userName %> </td>
</tr>
<tr>
<td> 年齡： </td>
<td> <%=age %> </td>
</tr>
<tr>
<td> 體重： </td>
<td> <%=weight %> kg </>
</tr>
<tr>
<td> 性別： </td>
<td> <%=sex %> </>
</tr>
</table>
<a href="login.jsp">返回</a>
</div>
</body>
</html>
//--------------------------------------------------------------------------------------------------------------------
fail.jsp 內容： <%@ page language="java" contentType="text/html;charset=gb2312" pageEncoding ="gb2312"%>
<html>
<head>
<title>登陸失敗</title>
</head>
<body>
<%
String userName = (String)session.getAttribute("username") ;
String msg = (String)session.getAttribute("message") ;
%>
<div align="center">
<%=userName %>
對不起，登陸失敗！<br />
<font color="red">原因： </font>
<%=msg %>
<br/>
<br/>
5秒後將返回登陸介面。
</div>
<%
response.setHeader("Refresh","5;URL=/learnJSP/login.jsp");
%>
</body>
</html>
//--------------------------------------------------------------------------------------------------------------------
mysql資料庫中需要建立資料庫learnJSP，其中建立表userInfo 建立表語句為：
create database learnJSP ;
use learnJSP
create table userInfo(id int not null primary key,username char(20) not null,userpsw char(20) ,age int ,weight int ,sex enum('M','F')) ;
需要把連線mysql的jar包放到專案的lib目錄中 //-------------------------------------------------------------------------------------------------------------------- web.xml 內容： <?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE web-app
PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"
<web-app>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>
LoginServlet
</servlet-name>
<servlet-class>
org.cai.servlet.LoginServlet
</servlet-class>
</servlet> <servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/LoginServlet</url-pattern>
</servlet-mapping>
</web-app>
//--------------------------------------------------------------------------------------------------------------------
登入頁面:login.jsp 登入成功歡迎頁面:success.jsp
登入失敗頁面:fail.jsp
Servlet處理檔案:LoginServlet.java 其實還涉及到一個檔案:web.xml,這個後面再說: 下面分別介紹這幾個檔案:
//--------------------------------------------------------------------------------------------------------------------
LoginServlet.java 內容： package org.cai.servlet ; import java.sql.* ;
import java.io.* ;
import javax.servlet.http.* ;
import javax.servlet.* ; public class LoginServlet extends HttpServlet implements Servlet{
public LoginServlet(){
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
}
// protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
// System.out.println("-------------------------") ;
// doPost(request, response) ;
// }
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
response.setContentType("text/html;charset=gb2312") ;
request.setCharacterEncoding("gb2312") ;
String result = "" ;
//獲取使用者名稱
String username = request.getParameter("username") ;
String psw = request.getParameter("password") ;
if ((username == "") || (username==null) || (username.length() > 20 )){
try{
result = "請輸入使用者名稱(不能超過20個字元)!" ;
request.setAttribute("message" ,result) ;
response.sendRedirect("login.jsp") ;
}catch(Exception e){
e.printStackTrace() ;
}
} if ((psw == "") || (psw==null) || (psw.length() > 20 )){
try{
result = "請輸入密碼(不能超過20個字元)!" ;
request.setAttribute("message" ,result) ;
response.sendRedirect("login.jsp") ;
}catch(Exception e){
e.printStackTrace() ;
}
}
//登記JDBC驅動程式
try{
Class.forName("org.gjt.mm.mysql.Driver") ;
}catch(ClassNotFoundException e){
e.printStackTrace() ;
System.out.println("Class Not Found Exception . ") ;
}
//連線URL
String url ="jdbc:mysql://localhost:3306/learnJSP" ;
Connection conn = null ;
Statement stmt = null ;
ResultSet rs = null ;
try{
conn = DriverManager.getConnection(url, "root", "root") ;
stmt = conn.createStatement() ;
//SQL語句
String sql ="select * from userInfo where username='"+username+"' and userpsw= '"+psw+"'" ;
rs = stmt.executeQuery(sql) ;//返回查詢結果
}catch(SQLException e){
e.printStackTrace() ;
}
HttpSession session = request.getSession() ;
session.setAttribute("username", username) ;
//System.out.println("+++++++++++++++++++++++"+ username) ;
try{
if (rs.next()){ //如果記錄集非空，表明有匹配的使用者名稱和密碼，登陸成功
// 登入成功後將username設定為session變數的username
// 這樣在後面就可以通過 session.getAttribute("username") 來獲取使用者名稱，
// 同時這樣還可以作為使用者登入與否的判斷依據
session.setAttribute("age",rs.getString("age")) ;
session.setAttribute("sex",rs.getString("sex")) ;
session.setAttribute("weight",rs.getString("weight")) ;
response.sendRedirect("success.jsp") ;
}else{
session.setAttribute("message", "使用者名稱或密碼不匹配。");
response.sendRedirect("fail.jsp") ;
}
}catch(SQLException e){
e.printStackTrace() ;
}
}
private static final long serialVersionUID = 1L; } //--------------------------------------------------------------------------------------------------------------------
login.jsp內容：
<%@ page language="java" contentType="text/html;charset=gb2312"%> <html>
<head>
<title>登陸</title>
</head>
<body>
<form method="POST" name="frmLogin" action="LoginServlet">
<h1 align="center">使用者登入</h1><br />
<center>
<table border=1>
<tr>
<td>使用者名稱：</td>
<td>
<input type="text" name="username" value="Your name" size="20" maxlength="20" onfocus="if (this.value=='Your name') this.value='';" />
</td>
</tr>
<tr>
<td>密 碼：</td>
<td>
<input type="password" name="password" value="Your password" size="20" maxlength="20" onfocus="if (this.value=='Your password') this.value='';" />
</td>
</tr>
<tr>
<td>
<input type="submit" name="Submit" value="提交" onClick="return validateLogin()" />
</td>
<td>
<input type="reset" name="Reset" value="重置" />
</td>
</tr>
</table>
</center>
</form>
<script language="javascript">
function validateLogin(){
var sUserName = document.frmLogin.username.value ;
var sPassword = document.frmLogin.password.value ;
if ((sUserName =="") || (sUserName=="Your name")){
alert("請輸入使用者名稱!");
return false ;
}
if ((sPassword =="") || (sPassword=="Your password")){
alert("請輸入密碼!");
return false ;
}
}
</script>
</body>
</html>
//--------------------------------------------------------------------------------------------------------------------
success.jsp 內容；
<%@ page language="java" contentType="text/html;charset=gb2312" pageEncoding ="gb2312"%>
<html>
<head>
<title>歡迎</title>
</head>
<body>
<%
String userName = (String)session.getAttribute("username") ;
String age = (String)session.getAttribute("age") ;
String weight = (String)session.getAttribute("weight") ;
String sex = (String)session.getAttribute("sex") ; System.out.println("性別：A" + sex +"A") ;
if (sex.trim().equals("M")) {
sex ="男" ;
}else{
sex = "女" ;
}
%>
<div align="center">
<%=userName %>
歡迎您，登陸成功！<br />
<font color="blue">登陸使用者資訊：</font>
<table border =1 >
<tr>
<td> 姓名： </td>
<td> <%=userName %> </td>
</tr>
<tr>
<td> 年齡： </td>
<td> <%=age %> </td>
</tr>
<tr>
<td> 體重： </td>
<td> <%=weight %> kg </>
</tr>
<tr>
<td> 性別： </td>
<td> <%=sex %> </>
</tr>
</table>
<a href="login.jsp">返回</a>
</div>
</body>
</html>
//--------------------------------------------------------------------------------------------------------------------
fail.jsp 內容： <%@ page language="java" contentType="text/html;charset=gb2312" pageEncoding ="gb2312"%>
<html>
<head>
<title>登陸失敗</title>
</head>
<body>
<%
String userName = (String)session.getAttribute("username") ;
String msg = (String)session.getAttribute("message") ;
%>
<div align="center">
<%=userName %>
對不起，登陸失敗！<br />
<font color="red">原因： </font>
<%=msg %>
<br/>
<br/>
5秒後將返回登陸介面。
</div>
<%
response.setHeader("Refresh","5;URL=/learnJSP/login.jsp");
%>
</body>
</html>
//--------------------------------------------------------------------------------------------------------------------
mysql資料庫中需要建立資料庫learnJSP，其中建立表userInfo 建立表語句為：
create database learnJSP ;
use learnJSP
create table userInfo(id int not null primary key,username char(20) not null,userpsw char(20) ,age int ,weight int ,sex enum('M','F')) ;
需要把連線mysql的jar包放到專案的lib目錄中 //-------------------------------------------------------------------------------------------------------------------- web.xml 內容： <?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE web-app
PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"
<web-app>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>
LoginServlet
</servlet-name>
<servlet-class>
org.cai.servlet.LoginServlet
</servlet-class>
</servlet> <servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/LoginServlet</url-pattern>
</servlet-mapping>
</web-app>
//--------------------------------------------------------------------------------------------------------------------