JSP基本登录模Ⅹ(Servlet过滤器验证Session)

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http://mgc.name/article.asp?id=124

使用Servlet过滤器验证Session

登录模块至少需要以下几个页面：

JSP模块：
1.输入用户信息页面(login.jsp)；
2.登录成功欢迎页面(pass.jsp)（检查Session设置）；
3.注销登录页面(logout.jsp)。

Servlet模块：
1.检查Cookie页面(index.mgc)(servlet:CheckCookie.java)；
2.用户合法性验证页面(check.mgc)(servlet:CheckMember.java)；

Filter模块：
验证Session(SessionFilter.java)；

DAO模块：
1.VO对象类(Member.java)；
2.数据库操作接口类(MemberDAO.java)；
3.数据库连接类(DataBaseConnection.java)；
4.数据库操作类(DAOMemberImpl.java)；
5.工厂类(DAOFactory.java)。

数据库：member.mdb

结构图：

---------------------------------------------------------------------

                 index.mgc
                       |
                       |判断Cookie中有无用户名、密码
          ----------------------
          |   Y                 N  |
          |                          V
          |                      login.jsp<--------------------
          |                          |输入用户名、密码           |
          |                          V                                  |
          ---------------->check.mgc                          |
                                      |调用DAO模块                |
                      查询数据库 V                                  |
        member.mdb<--->DAO                              |
                                      |返回结果                      |
                                      V                                  |
                                 check.mgc                         |
                                      |判断用户是否合法          |
                          ---------------------                     |
                          |  Y                N  |                     |
                          V                       V                    |
                      pass.jsp           跳转--------------->|
                          |                                              |
                          | 检查session是否含有用户名      |
                -----------------                                    |
                | Y             N |                                    |
                V                  V                                   |
           pass.jsp          跳转------------------------->|
                |                                                        |
                |注销                                                  |
                V                                                       |
          logout.jsp------------------------------------>|

---------------------------------------------------------------------

CheckCookie.java:

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package mgc.login.mvc.servlet; 
  
import java.io.*; 
import javax.servlet.*; 
import javax.servlet.http.*; 
import mgc.dao.login.member.*; 
  
public class CheckCookie extends HttpServlet { 
  
  
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
  
        this.doPost(request, response); 
    }         
    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
  
        String username=null; 
        String password=null; 
        //取得Cookie的全部属性 
        Cookie c[]=request.getCookies(); 
        int i; 
        for(i=0;i<c.length;i++) { 
              
            if("username".equals(c[i].getName())) { 
                  
                //Cookie中有用户名，保存 
                username=c[i].getValue(); 
            } 
            if("password".equals(c[i].getName())) { 
                  
                //Cookie中有密码，保存 
                password=c[i].getValue(); 
            } 
        } 
        if(username!=null && password!=null) { 
              
            //Cookie中含有用户名和密码，提交跳转到用户验证页面 
            request.setAttribute("username", username); 
            request.setAttribute("password",password); 
            request.getRequestDispatcher("check.mgc").forward(request,response); 
        } 
        else { 
              
            //Cookie中没有用户名、密码，跳转到登录页面 
            response.sendRedirect("login.jsp"); 
        } 
    } 
  
}

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<%@ page contentType="text/html;charset=GB2312" %> 
<%@ page import="java.util.*" %> 
<html> 
  <head> 
    <title>登录</title> 
  </head> 
    
  <body> 
      <center> 
      <h1>登录页面</h1> 
      <hr> 
<% 
    //接收错误信息 
    List errors=(List)request.getAttribute("errors"); 
    if(errors!=null) { 
      
        //有错误信息，全部打印 
        Iterator iter=errors.iterator(); 
        while(iter.hasNext()) { 
          
%> 
            <h4><font color="red">*<%=iter.next() %></font></h4> 
<% 
        } 
    } 
%> 
    <form action="check.mgc" method="post"> 
        <table> 
            <tr> 
                <td>用户名：</td> 
                <td><input type="text" name="username" value="${member.username } " /></td> 
            </tr> 
            <tr> 
                <td>密  码：</td> 
                <td><input type="password" name="password" /></td> 
            </tr> 
            <tr> 
            <td>Cookie选项：</td> 
            <td> 
                <input type="radio" name="cookie" value="nosave" checked>不保存 
                <input type="radio" name="cookie" value="save">保存1分钟 
            </td> 
            </tr> 
            <tr> 
                <td colspan="2" align="center"> 
                    <input type="submit" value="登录" />  
                    <input type="reset" value="重置" /> 
                </td> 
            </tr> 
        </table> 
    </form> 
    </center> 
  </body> 
</html>

CheckMember.java:

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package mgc.login.mvc.servlet; 
  
import java.io.*; 
import java.util.*; 
import javax.servlet.*; 
import javax.servlet.http.*; 
import mgc.login.mvc.vo.*; 
import mgc.login.mvc.factory.*; 
  
public class CheckMember extends HttpServlet { 
  
  
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
  
        this.doPost(request, response); 
    }         
    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
  
        String username=request.getParameter("username"); 
        String password=request.getParameter("password"); 
        String savecookie=request.getParameter("cookie"); 
        List errors=new ArrayList(); 
        Member mem=new Member(); 
        mem.setUsername(username); 
        mem.setPassword(password); 
        mem.setErrors(errors); 
        String path="login.jsp"; 
        if(!mem.isEmpty()) { 
              
            //用户名、密码不为空，验证 
            try{ 
                  
                //判断用户名、密码的合法性 
                if(DAOFactory.getMemberInstance().isUser(mem)) 
                { 
                    //合法用户 
                    //设置跳转页面为欢迎页面 
                    path="pass.jsp"; 
                    //设置session属性 
                    request.getSession().setAttribute("username",mem.getUsername()); 
                    if("save".equals(savecookie)) { 
                          
                        //如果选择了保存Cookie选项，则保存Cookie 
                        Cookie c1=new Cookie("username",mem.getUsername()); 
                        Cookie c2=new Cookie("password",mem.getPassword()); 
                        //设置Cookie保存时间为1分钟 
                        c1.setMaxAge(60); 
                        c2.setMaxAge(60); 
                        response.addCookie(c1); 
                        response.addCookie(c2); 
                    } 
                } 
                else { 
                      
                    errors.add("用户名或密码错误！"); 
                } 
            } 
            catch(Exception e) { 
                  
                System.out.println(e); 
            }  
        } 
        //保存错误信息 
        request.setAttribute("errors", errors); 
        //保存用户信息 
        request.setAttribute("member", mem); 
        //跳转 
        request.getRequestDispatcher(path).forward(request, response); 
    } 
}

pass.jsp:

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<%@ page contentType="text/html;charset=GB2312" %> 
<html> 
  <head> 
    <title>登录成功</title> 
  </head> 
    
  <body> 
    <center> 
        <h1>登录成功!!</h1> 
        <hr> 
        <h3>欢迎<font size="12" color="red"> 
        <%--forward跳转为服务器端跳转，跳转后仍在check.jsp页面，可以继续使用usename参数 --%> 
        <%=request.getParameter("username") %> 
        </font>光临！</h3> 
        <p> 
        <a href="logout.jsp">注销登录</a> 
    </center> 
  </body> 
</html>

logout.jsp:

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<%@ page contentType="text/html;charset=GB2312" %> 
<html> 
  <head> 
    <title>注销登录</title> 
  </head> 
    
  <body> 
    <% 
        //使session失效 
        session.invalidate(); 
    %> 
    <center> 
        <h1>注销成功！</h1> 
        3秒后跳转到登录页面 
        <p> 
        如果没有跳转，请点<a href="login.jsp">这里</a> 
    <% 
        response.setHeader("refresh","3;URL=login.jsp"); 
    %> 
    </center> 
  </body> 
</html>

SessionFilter.java:

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package mgc.filter.test; 
  
import java.io.*; 
import javax.servlet.*; 
import javax.servlet.http.*; 
  
public class SessionFilter implements Filter { 
  
    public void init(FilterConfig conf) throws ServletException { 
          
    } 
      
    public void doFilter(ServletRequest request,ServletResponse response,FilterChain chain ) throws IOException,ServletException { 
          
        HttpServletRequest req = (HttpServletRequest) request; 
        String username = (String)req.getSession().getAttribute("username"); 
        if(username!=null) { 
              
            //Session中含有用户名 
            chain.doFilter(request, response); 
        } 
        else { 
              
            //Session中没有用户名，跳转到登录页面 
            req.getRequestDispatcher("login.jsp").forward(request, response); 
        } 
    } 
      
    public void destroy() { 
          
    } 
}

Member.java:

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package mgc.login.mvc.vo; 
  
import java.util.*; 
  
public class Member { 
      
    private String username; 
    private String password; 
    private List errors; 
      
    public void setUsername(String username) { 
          
        this.username=username; 
    } 
      
    public void setPassword(String password) { 
          
        this.password=password; 
    } 
      
    public void setErrors(List errors) { 
          
        this.errors=errors; 
    } 
      
    public String getUsername() { 
          
        return this.username; 
    } 
      
    public String getPassword() { 
          
        return this.password; 
    } 
      
    public List getErrors() { 
          
        return this.errors; 
    } 
      
    public boolean isEmpty() { 
          
        boolean iserror=false; 
        if(this.username==null || "".equals(this.username)) { 
              
            iserror=true; 
            this.errors.add("用户名不能为空！"); 
        } 
        if(this.password==null || "".equals(this.password)) { 
              
            iserror=true; 
            this.errors.add("密码不能为空！"); 
        } 
        return iserror; 
    } 
      
}

MemberDAO.java:

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package mgc.login.mvc.dao; 
  
import mgc.login.mvc.vo.*; 
  
public interface MemberDAO { 
    //判断用户是否合法 
    public boolean isUser(Member member) throws Exception; 
}

DataBaseConnection.java:

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package mgc.login.mvc.dbc; 
  
import java.sql.*; 
import java.sql.DriverManager; 
  
public class DataBaseConnection { 
      
    private final String DBDRIVER="sun.jdbc.odbc.JdbcOdbcDriver"; 
    private final String DBURL="jdbc:odbc:member"; 
    private Connection conn=null; 
      
    public DataBaseConnection() { 
        try{ 
            Class.forName(DBDRIVER); 
            this.conn=DriverManager.getConnection(DBURL); 
        } 
        catch(Exception e){} 
    } 
      
    public Connection getConnection() { 
        return this.conn; 
    } 
      
    public void close() { 
        try{ 
            this.conn.close(); 
        } 
        catch(Exception e){} 
    } 
}

DAOMemberImpl.java:

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package mgc.login.mvc.impl; 
  
import java.sql.*; 
import mgc.login.mvc.vo.*; 
import mgc.login.mvc.dao.*; 
import mgc.login.mvc.dbc.*; 
  
public class MemberDAOImpl implements MemberDAO { 
    public boolean isUser(Member member) throws Exception { 
        //设置标志，判断数据库中是否有符合查询条件的记录，true表示有，false表示没有 
        boolean is_user=false; 
        String sql="Select * FROM member Where username=? AND password=?"; 
        PreparedStatement pstmt=null; 
        ResultSet rs=null; 
        DataBaseConnection dbc=null; 
        try{ 
            dbc=new DataBaseConnection(); 
            pstmt=dbc.getConnection().prepareStatement(sql); 
            pstmt.setString(1, member.getUsername()); 
            pstmt.setString(2, member.getPassword()); 
            rs=pstmt.executeQuery(); 
            if(rs.next()){ 
                //有符合查询条件的记录 
                is_user=true; 
            } 
            rs.close(); 
            pstmt.close(); 
        } 
        catch(Exception e){ 
            throw new Exception("数据库操作失败"); 
        } 
        finally{ 
            dbc.close(); 
        } 
        return is_user; 
    } 
}

DAOFactory.java:

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package mgc.login.mvc.factory; 
  
import mgc.login.mvc.dao.*; 
import mgc.login.mvc.impl.*; 
  
public class DAOFactory { 
    public static MemberDAO getMemberInstance() { 
        return new MemberDAOImpl(); 
    } 
}

web.xml:

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  <servlet> 
    <servlet-name>CheckCookie</servlet-name> 
    <servlet-class>mgc.login.mvc.servlet.CheckCookie</servlet-class> 
  </servlet> 
  <servlet> 
    <servlet-name>CheckMember</servlet-name> 
    <servlet-class>mgc.login.mvc.servlet.CheckMember</servlet-class> 
  </servlet> 
  <filter> 
      <filter-name>SessionFilter</filter-name> 
      <filter-class>mgc.filter.test.SessionFilter</filter-class> 
  </filter> 
  
  <servlet-mapping> 
    <servlet-name>CheckCookie</servlet-name> 
    <url-pattern>/login/filter/index.mgc</url-pattern> 
  </servlet-mapping> 
  <servlet-mapping> 
    <servlet-name>CheckMember</servlet-name> 
    <url-pattern>/login/filter/check.mgc</url-pattern> 
  </servlet-mapping> 
  <filter-mapping> 
      <filter-name>SessionFilter</filter-name> 
      <url-pattern> /login/filter/pass.jsp</url-pattern> 
  </filter-mapping>