IT兄弟連 JavaWeb教程經典案例

時間 2019-12-06

原文原文鏈接

案例需求：編寫一個jsp servlet程序,在login.jsp發起login.do登陸請求，當輸入的用戶名是abc密碼是123時，則判斷是登陸成功，其它暫時認爲是登陸失敗。當用戶登陸成功時，將用戶名放入session對象中並跳轉到main.jsp。當用戶登陸失敗時向request對象中存放一個msg消息，內容是登陸失敗。再發送一個orderInfo.do的查看訂單信息的請求，能夠跳轉到orderInfo.jsp。在上面程序的基礎上,寫一個過濾器，要求用戶登陸成功才能查看訂單信息。html

案例實現：java

● login.jsp:session

<%@ page language="java" contentType="text/html; charset=utf-8"jsp

pageEncoding="utf-8"%>ide

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">ui

<html>spa

<head>orm

<title>Insert title here</title>對象

</head>

<body>

用戶名:<input type="text" name="username" > <br>

密碼: <input type="password" name="userpassword" > <br>

</form>

</body>

</html>

● main.jsp：

<%@ 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>

<title>Insert title here</title>

</head>

<body>

<h1> 歡迎 ${username} </h1>

</body>

</html>

● orderInfo.jsp：

<%@ 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>

<title>Insert title here</title>

</head>

<body>

<h1> 查看訂單信息中.... </h1>

</body>

</html>

● XdlUserLoginController.java :

package com.xdl.controller;

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.annotation.WebServlet;

@WebServlet("/login.do")

public class XdlUserLoginController extends HttpServlet {

@Override

protected void service(HttpServletRequest request,

HttpServletResponse response) throws ServletException, IOException {

// 獲取頁面請求參數

String username = request.getParameter("username");

String userpassword = request.getParameter("userpassword");

System.out.println("登陸中...");

if("abc".equals(username) && "123".equals(userpassword)){

request.getSession().setAttribute("username", username);

response.sendRedirect("main.jsp");

}else{

request.setAttribute("msg", "登陸失敗");

request.getRequestDispatcher("login.jsp").

forward(request, response);

}

● XdlOrderInfoController.java:

package com.xdl.controller;

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;

@WebServlet("/orderInfo.do")

public class XdlOrderInfoController extends HttpServlet {

private static final long serialVersionUID = 1L;

protected void service(HttpServletRequest request,

HttpServletResponse response) throws ServletException, IOException {

request.getRequestDispatcher("orderInfo.jsp").

forward(request, response);

}

● 檢查登陸的過濾器:

package com.xdl.filter;

import java.io.IOException;

import javax.servlet.Filter;

import javax.servlet.FilterChain;

import javax.servlet.FilterConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletRequest;

import javax.servlet.ServletResponse;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

@WebFilter("*.do")

public class XdlCheckLoginFilter implements Filter {

@Override

public void destroy() {

}

@Override

public void doFilter(ServletRequest arg0, ServletResponse arg1,

FilterChain chain)

throws IOException, ServletException {

// 放行若是用戶已經登陸了則放行若是沒登陸則跳轉到登陸頁面

// 注意登陸請求時不能攔截的是否登陸參考的是 session 有沒有 username

HttpServletRequest request = (HttpServletRequest)arg0;

HttpServletResponse response = (HttpServletResponse)arg1;

String servletPath = request.getServletPath();

if("/login.do".equals(servletPath)){

chain.doFilter(arg0, arg1);

}else{

/* System.out.println("此路是我開此樹是我栽要想今後過留下李偉傑");

chain.doFilter(arg0, arg1);

System.out.println("你回來了? 怎麼又是你你走吧"); */

String username = (String)

request.getSession().getAttribute ("username");

if(username == null){

// 跳轉到登陸頁面

response.sendRedirect("login.jsp");

}else{

chain.doFilter(arg0, arg1);

}

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IT兄弟連 JavaWeb教程 經典案例

IT兄弟連 JavaWeb教程經典案例