SQL防止重复提交和Filter
/class User
package com.neuedu.bean;
import java.io.Serializable;
public class User implements Serializable{
private static final long serialVersionUID = 1L;
private int password;
private String name;
public User() {
super();
}
public User(int password, String name) {
super();
this.password = password;
this.name = name;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getPassword() {
return password;
}
public void setPassword(int password) {
this.password = password;
}
@Override
public String toString() {
return "password=" + password + ", name=" + name;
}
}
/class LoginDao
package com.neusoft.dao; import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException; import com.neuedu.bean.User;
import com.neusoft.utils.JDBCUtil; public class LoginDao {
public User getUser(String name,String password){
User user=null;
PreparedStatement ps=null;
ResultSet rs =null;
Connection conn=JDBCUtil.getConnection();
String sql="select * from t_user where password= ? and name =?";
try {
ps = conn.prepareStatement(sql);
ps.setString(, password);
ps.setString(, name);
rs = ps.executeQuery();
while (rs.next()) {
String username = rs.getString("name");
int password2 = rs.getInt("password");
user=new User(password2,username);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally {
JDBCUtil.close(ps, rs, conn);
}
return user; }
public void Add(String name,String password,String email){ PreparedStatement ps=null;
Connection conn=JDBCUtil.getConnection();
String sql="insert into t_user values(?,?,?,?)";
try {
ps = conn.prepareStatement(sql);
ps.setString(, null);
ps.setString(, name);
ps.setString(, password);
ps.setString(, email);
ps.executeUpdate();
System.out.println(ps.toString());
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally { if (ps !=null) {
try {
ps.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (conn !=null) {
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
public void Update(String name,String password,String email){ PreparedStatement ps=null;
Connection conn=JDBCUtil.getConnection();
String sql="update t_user set name=?,pasword=?,mail=? where id=?";
try {
ps = conn.prepareStatement(sql);
ps.setString(, null);
ps.setString(, name);
ps.setString(, password);
ps.setString(, email);
ps.executeUpdate();
System.out.println(ps.toString());
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally { if (ps !=null) {
try {
ps.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (conn !=null) {
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
/class AFilter
package com.neusoft.servlet; 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.annotation.WebFilter; @WebFilter( "/LoginServlet" )
public class AFilter implements Filter { public void destroy() {
// TODO Auto-generated method stub
} public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
System.out.println("AFilter此路是我开，此树是我栽！");
String name = request.getParameter("username");
if (name.equals("qwe")) {
chain.doFilter(request, response);
System.out.println("AFilter要想从此过，留下买路财！");
}else {
request.getRequestDispatcher("/Login.jsp").forward(request, response);//转发
} } public void init(FilterConfig fConfig) throws ServletException {
// TODO Auto-generated method stub
} }
/class BFilter
package com.neusoft.servlet; 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.annotation.WebFilter; @WebFilter("/LoginServlet")
public class BFilter implements Filter { public void destroy() {
// TODO Auto-generated method stub
} public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
System.out.println("BFilter此路是我开，此树是我栽！");
String psd = request.getParameter("pwd");
if (psd.equals("")) {
chain.doFilter(request, response);
System.out.println("BFilter要想从此过，留下买路财！");
}else {
request.getRequestDispatcher("/Login.jsp").forward(request, response);//转发
} } public void init(FilterConfig fConfig) throws ServletException {
// TODO Auto-generated method stub
} }
/class LoginServlet
package com.neusoft.servlet; import java.io.IOException;
import java.util.ArrayList;
import java.util.List; 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; import com.neuedu.bean.User;
import com.neusoft.dao.LoginDao; @WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
private static final long serialVersionUID = 1L; protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String reqUUID = request.getParameter("uuid");
HttpSession session = request.getSession();
String sessUUID =(String)session.getAttribute("uuid");
session.removeAttribute("uuid");//防止重复提交
try {
Thread.sleep(*);//休眠3秒 String name = request.getParameter("username");
String psd = request.getParameter("pwd");
System.out.println(name);
User user=new LoginDao().getUser(name, psd);
if (user !=null&&reqUUID.equals(sessUUID)) {
// List<User>List=new ArrayList<User>();
// List.add(user);
request.setAttribute("user", user);
System.out.println(user);
// response.sendRedirect(request.getContextPath()+"/login-success.jsp");//重定向
request.getRequestDispatcher("/login-success.jsp").forward(request, response);//转发
}else {
request.setAttribute("errorMsg", "不要重复提交！");
request.getRequestDispatcher("/Login.jsp").forward(request, response);//转发
}
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
doGet(request, response);
} }
/class OUTServlet
package com.neusoft.servlet; 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;
import javax.servlet.http.HttpSession;
import javax.swing.JOptionPane; @WebServlet("/OUTServlet")
public class OUTServlet extends HttpServlet {
private static final long serialVersionUID = 1L; protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
HttpSession session = request.getSession();
session.invalidate();//清除会话，也就是清除参数
JOptionPane.showMessageDialog(null,"您已退出，请重新登录");
response.sendRedirect(request.getContextPath()+"/Login.jsp");//重定向
} protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response);
} }
/class JDBCUtil
package com.neusoft.utils; import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement; public class JDBCUtil {
private static String driver="com.mysql.jdbc.Driver";
private static String url="jdbc:mysql://localhost:3306/demo";
private static String username="root";
private static String password="";
static{ try {
Class.forName(driver);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
} }
public static Connection getConnection(){
try {
return DriverManager.getConnection(url, username, password);
} catch (SQLException e) {
// TODO Auto-generated catch block
return null;
}
} public static void close(Statement st,ResultSet rs,Connection conn){
if (conn !=null) {
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (rs !=null) {
try {
rs.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (st !=null) {
try {
st.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
/Login.jsp
<%@page import="java.util.UUID"%>
<%@ 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>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<%
String uuid=UUID.randomUUID().toString();
session.setAttribute("uuid", uuid);
%>
${errorMsg}
<form action="${pageContext.request.contextPath}/LoginServlet" method="post">
<input type="hidden" name="uuid" value="<%=uuid%>"/>
用户名：<input type="text" name="username"/>
密码：<input type="password" name="pwd"/>
<input type="submit" value="提交"/>
</form>
<a href="Regist.html">去注册</a>
</body>
</html>
<%@page import= "com.neuedu.bean.User"%>
<%@page import="java.util.ArrayList"%>
<%@page import="java.util.List"%>
<%@ 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>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<table border="1" align="center" width="50%">
<tr>
<th>姓名 </th>
<th>密码 </th>
<th colspan="2"> </th>
</tr>
<%-- <%
List<User>stuList=new ArrayList<User>();
stuList=(List<User>)request.getAttribute("stuList");
for(int i=0;i<stuList.size();i++){
User user=stuList.get(i);
%> --%>
<tr>
<td><%-- <%=user.getName() %> --%>${user.name}</td>
<td><%-- <%=user.getPassword() %> --%>${user.password}</td>
<td><a href="#">修改</a></td>
<td><a href="#">删除</a></td>
</tr>
<%-- <%
}
%> --%> </table>
<form action="${pageContext.request.contextPath}/OUTServlet" >
<input type="submit"value="退出"/>
</form>
</body>
</html>
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