專注Java教育14年
全國咨詢/投訴熱線：400-8080-105
更新時(shí)間：2021-04-28 13:39:02 來源：動(dòng)力節(jié)點(diǎn) 瀏覽933次
JDK1.8 + Tomcat1.8
(1)fail.html頁面
<!DOCTYPE html>
<html>
<head>
<title>faill.html</title>
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="this is my page">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<!--<link rel="stylesheet" type="text/css" href="./styles.css" rel="external nofollow" rel="external nofollow" >-->
</head>
<body>
<font color='red' size='3'>親， 你的用戶名或密碼輸入有誤！請(qǐng)重新輸入!</font>
<br />
<a href="/project03/login.html" >返回登錄頁面</a>
</body>
</html>
(2)Login.htm頁面
<!DOCTYPE html>
<html>
<head>
<title>Login.html</title>
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="this is my page">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<!--<link rel="stylesheet" type="text/css" href="./styles.css" >-->
</head>
<body>
<form action="/project03/LoginServlet" method="post">
用戶名：<input type="text" name="UserName" /><br />
密 碼：<input type="password" name="UserPwd" /><br />
<input type="submit" value="登錄" />
</form>
</body>
</html>
(3)IndexServlet.java
package cn.itcase.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
* 用戶主頁邏輯
* */
public class IndexServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 設(shè)置編碼格式
response.setContentType("text/html;charset=utf-8");// setContentType設(shè)置瀏覽器的編碼格式
// 1.信息輸出至瀏覽器
PrintWriter writer = response.getWriter();
String html = "";
/**
* 接收request域?qū)ο蟮臄?shù)據(jù) String loginName =
* (String)request.getAttribute("loginName",userName);
*
*/
/**
* 在用戶主頁，判斷session對(duì)象不為空且存在指定的屬性則登錄成功 才能訪問資源。從session域?qū)ο笾腥〕鰰?huì)話數(shù)據(jù)
*
*
* */
// 2.得到session對(duì)象
HttpSession session = request.getSession(false);
// 2.1如果不存在session對(duì)象，登錄不成功，跳轉(zhuǎn)到登錄頁面
if (session == null) {
response.sendRedirect(request.getContextPath()
+ "/Login.html");
return;
}
// 2.2沒有在session對(duì)象域中找到相應(yīng) session唯一標(biāo)識(shí)ID 則登錄不成功，跳轉(zhuǎn)到登錄頁面
String loginName = (String) session.getAttribute("loginName");
if (loginName == null) {
response.sendRedirect(request.getContextPath() + "/Login.html");
return;
}
html = "<html><body>歡迎回來，" + loginName + "，<a href='"
+ request.getContextPath()
+ "/LogoutServlet'>安全退出</a></body></html>";
writer.write(html);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
(4)LoginServlet.java
package cn.itcase.servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
* 登錄的邏輯
* 設(shè)置編碼格式
* 根據(jù)參數(shù)名獲取參數(shù)值
* 判斷邏輯（使用session域?qū)ο螅?
*
*
*/
public class LoginServlet extends HttpServlet {
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
// 設(shè)置編碼格式
request.setCharacterEncoding("utf-8");// setCharacterEncoding設(shè)置服務(wù)器的編碼格式
// 1.根據(jù)參數(shù)名獲取參數(shù)值
String userName = request.getParameter("UserName");
String userPwd = request.getParameter("UserPwd");
// 2.登錄是否的邏輯判斷
if("eric".equals(userName) && "123456".equals(userPwd)){
/**分析使用技術(shù)：
* context域?qū)ο螅翰缓线m，可能會(huì)覆蓋數(shù)據(jù)
* request.setAttribute("loginName",userName);
*
* request域?qū)ο螅翰缓线m，整個(gè)網(wǎng)站必須得使用轉(zhuǎn)發(fā)技術(shù)來跳轉(zhuǎn)
* request.getRequestDispatcher("/IndexServlet").forward(request,response);
*
* session域?qū)ο螅汉线m
* response.sendRedirect(request.getContextPath()+"/IndexServlet")
* */
//2.1 登錄成功
// 2.1.1創(chuàng)建session對(duì)象 用于保存數(shù)據(jù)
HttpSession session = request.getSession();
// 2.1.1把數(shù)據(jù)保存到session域中
session.setAttribute("loginName", userName); // session對(duì)象的唯一標(biāo)識(shí)"loginName" 唯一標(biāo)識(shí)名稱 userName
//session.setMaxInactiveInterval(1*60*60*24*30); // session對(duì)象的有效時(shí)長 可以配置全局的有效時(shí)長
//2.1.3跳轉(zhuǎn)到用戶主頁
response.sendRedirect(request.getContextPath() + "/IndexServlet"); //sendRedirect()重定向 getContextPath()請(qǐng)求路徑
}else{
//2.2登錄失敗 請(qǐng)求重定向
response.sendRedirect(request.getContextPath() + "/fail.html");
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setCharacterEncoding("utf-8");
doGet(request,response);
}
}
(5)LogoutServlet.java
package cn.itcase.servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
* 退出邏輯
* */
public class LogoutServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
/**
* 安全退出
* 刪除session對(duì)象中指定的loginName屬性即可
*
*/
HttpSession session = request.getSession(false);
if(session != null){
session.removeAttribute("loginName");
}
//返回登錄頁面
response.sendRedirect(request.getContextPath() + "/Login.html");
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
}
}
以上就是動(dòng)力節(jié)點(diǎn)小編介紹的"Java登錄代碼案例"的內(nèi)容，希望對(duì)大家有幫助，如有疑問，請(qǐng)?jiān)诰€咨詢，有專業(yè)老師隨時(shí)為您服務(wù)。
Java實(shí)驗(yàn)班
0基礎(chǔ) 0學(xué)費(fèi) 15天面授
Java就業(yè)班
有基礎(chǔ) 直達(dá)就業(yè)
Java夜校直播班
業(yè)余時(shí)間 高薪轉(zhuǎn)行
Java在職加薪班
工作1~3年，加薪神器
Java架構(gòu)師班
工作3~5年，晉升架構(gòu)
提交申請(qǐng)后，顧問老師會(huì)電話與您溝通安排學(xué)習(xí)
官方微信
官方抖音
京公網(wǎng)安備 11030102010736號(hào)