本篇博客介紹的是Session 的設置及應用的事例,這個事例用到了一個html的代碼login.html和三個Servlet的程序login.do user.view
logout這三個分別是用戶登錄的時的判斷，用戶的session的記錄以及用戶的註銷下面附上代碼（重要的部分帶有註釋）
login.html
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>歡迎登錄</title>
</head>
<body>
<form action="login.do" method="post">
用戶名:<input type="text" name="user"><br/>
密碼:<input type="password" name="password"><br/>
<input type="submit" value="提交">
</form>
</body>
</html>login.do
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");//設置字符
PrintWriter out =response.getWriter();
String user=request.getParameter("user");//取得用戶姓名
String password=request.getParameter("password");//取得用戶密碼
if("wanglin".equals(user) &&"123456".equals(password))//判斷
{
HttpSession session=request.getSession(true);//false 沒有的話也不新建
session.setAttribute("login", user);//添加login屬性
request.getRequestDispatcher("user.view").forward(request,response);//forward方法的運用
}
else
response.sendRedirect("login.html");//重定向
}user
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
HttpSession session =request.getSession();//獲得請求裏面的session
if(session.getAttribute("login")==null)
{
response.sendRedirect("login.html");
}
else
{
response.setContentType("text/html;charset=UTF-8");
PrintWriter out=response.getWriter();
String user=(String)session.getAttribute("login");//獲得session 屬性
String id=session.getId();
out.println(user+"已登錄"+"ID"+"爲:"+id);
out.print("<a href='logout.view'>註銷</a>");
}
}logout
package xhxy;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
* Servlet implementation class Logout
*/
@WebServlet("/logout.view")
public class Logout extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public Logout() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
HttpSession session=request.getSession();
response.setContentType("text/html;charset=UTF-8");
PrintWriter out =response.getWriter();
String name=(String)session.getAttribute("login");
out.println(name+"已註銷");
session.invalidate();
}
}