工具类封装JDBC
package com.bjpowernode.oa.utils;
import java.sql.*;
import java.util.ResourceBundle;
public class DBUtil
{
private static ResourceBundle bundle = ResourceBundle.getBundle("resources.jdbc");
private static String driver = bundle.getString("driver");
private static String url = bundle.getString("url");
private static String user = bundle.getString("user");
private static String password = bundle.getString("password");
//JDBC工具类
static
{
//注册驱动
try
{
// Class.forName("com.mysql.jdbc.Driver");//避免写死
Class.forName(driver);
}
catch (ClassNotFoundException e)
{
throw new RuntimeException(e);
}
}
public static Connection getConnection() throws SQLException {
//获取链接
return DriverManager.getConnection(url,user,password);
}
//释放资源
public static void close(Connection connection, Statement statement, ResultSet resultSet)
{
if (resultSet != null) {
try {
resultSet.close();
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
if (statement != null) {
try {
statement.close();
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
if (connection != null) {
try {
connection.close();
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
}
}封装用户信息的POJO类ORM对象
package com.bjpowernode.oa.Pojo;
import jakarta.servlet.ServletContext;
import jakarta.servlet.http.HttpSessionBindingEvent;
import jakarta.servlet.http.HttpSessionBindingListener;
public class User implements HttpSessionBindingListener
{
private String username;
private String password;
public User() {
}
@Override
public String toString() {
return "User{" +
"username='" + username + '\'' +
", password='" + password + '\'' +
'}';
}
@Override
public void valueBound(HttpSessionBindingEvent event) {
ServletContext application = event.getSession().getServletContext();
Long onlineCount = (Long)application.getAttribute("onlineCount");
if(onlineCount == null)
{
application.setAttribute("onlineCount",1L);
}
else
{
onlineCount++;
application.setAttribute("onlineCount",onlineCount);
}
}
@Override
public void valueUnbound(HttpSessionBindingEvent event) {
//因为是推出登录,所以必定不会是null空值
ServletContext application = event.getSession().getServletContext();
Long onlineCount = (Long)application.getAttribute("onlineCount");
onlineCount--;
application.setAttribute("onlineCount",onlineCount);
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public User(String username, String password) {
this.username = username;
this.password = password;
}
}封装部门信息的ORM对象
package com.bjpowernode.oa.Pojo;
import java.util.Objects;
public class Dept
{
private String deptno;
private String dname;
private String loc;
@Override
public String toString() {
return "Dept{" +
"deptno='" + deptno + '\'' +
", dname='" + dname + '\'' +
", loc='" + loc + '\'' +
'}';
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Dept dept = (Dept) o;
return Objects.equals(deptno, dept.deptno) && Objects.equals(dname, dept.dname) && Objects.equals(loc, dept.loc);
}
@Override
public int hashCode() {
return Objects.hash(deptno, dname, loc);
}
public String getDeptno() {
return deptno;
}
public void setDeptno(String deptno) {
this.deptno = deptno;
}
public String getDname() {
return dname;
}
public void setDname(String dname) {
this.dname = dname;
}
public String getLoc() {
return loc;
}
public void setLoc(String loc) {
this.loc = loc;
}
public Dept() {
}
public Dept(String deptno, String dname, String loc) {
this.deptno = deptno;
this.dname = dname;
this.loc = loc;
}
}对没有登录的对象进行拦截的filter
package com.bjpowernode.oa.filter;
import jakarta.servlet.*;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.HttpSession;
import java.io.IOException;
public class LoginFilter implements Filter {
@Override
public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException
{
HttpServletRequest request = (HttpServletRequest)req;
HttpServletResponse response = (HttpServletResponse)res;
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
HttpSession session = request.getSession(false);
if(session != null && session.getAttribute("user") != null)
{
chain.doFilter(request,response);
}
else
{
response.sendRedirect(request.getContextPath() + "/index.jsp");
}
}
}默认欢迎页,主要用来实现Cookie自动登录效果
package com.bjpowernode.oa.action;
import com.bjpowernode.oa.Pojo.User;
import com.bjpowernode.oa.utils.DBUtil;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.*;
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
@WebServlet("/Welcome")
public class Welcome extends HttpServlet
{
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
Cookie[] cookies = request.getCookies();
String username = null;
String password = null;
if (cookies != null)
{
for(int i = 0; i < cookies.length; i++)
{
if("username".equals(cookies[i].getName()))
{
username = cookies[i].getValue();
}
if("password".equals(cookies[i].getName()))
{
password = cookies[i].getValue();
}
}
}
if(username != null && password != null)
{
Connection connection = null;
PreparedStatement statement = null;
ResultSet resultSet = null;
boolean flag = false;
try
{
connection = DBUtil.getConnection();
String sql = "select * from t_user where username = ? and pssword = ?";
statement = connection.prepareStatement(sql);
statement.setString(1,username);
statement.setString(2,password);
resultSet = statement.executeQuery();
if(resultSet.next())
{
flag = true;
}
}
catch (SQLException e)
{
throw new RuntimeException(e);
}
finally
{
DBUtil.close(connection,statement,resultSet);
}
if(flag)
{
HttpSession session = request.getSession();
session.setAttribute("user",new User(username,password));
response.sendRedirect(request.getContextPath() + "/dept/list");
}
else
{
response.sendRedirect(request.getContextPath() + "/index.jsp");
}
}
else
{
response.sendRedirect(request.getContextPath() + "/index.jsp");
}
}
}JSessionID=??这个键值对数据就是cookie保存的信息
对于session关联的cookie来说,这个cookie是保存在浏览器的运行内存中的
用户再次发送请求的时候,会自动把运行内存中的cookie放到请求头内一并发送
服务器就是根据这个值找到对应的对象
session存储在服务器上的,cookie是储存在电脑机器上的
cookie可以存在浏览器运行内存中,也可以放在硬盘内保存
cookie和session都是为了保存会话的状态
这两个机制存在的目的就是为了解决我们的http协议的无状态无连接协议的问题
(无状态无连接)没有请求和响应时,双方不知道对方是否还在
将购物车中的商品编号放到cookie当中,cookie保存到硬盘
下一次再打开,自动读取本地cookie,就还会显示这些商品
购物网站未登录不允许查看商品和保存购物车的原理是,为了记录数据,什么用户喜欢什么样的东西
和针对不同用户给出不同的优惠力度(大数据杀熟),并且可以防止爬虫,和减轻服务器压力(没有购买欲望的客户不让你看)
十天免登录的实现原理如下,保存一个记录了用户名和密码的cookie到本地
当十天内再次访问该网站时,会自动在请求头内发送这个账号用户名和密码到服务器,服务器接收到这个cookie
解密后实现登录
cookie和session都是Http协议的一部分,因为Http协议是无状态和无连接的协议
Http协议规定,任何一个cookie都是由name和value组成的
在java的servlet中,对cookie提供了那些支持?
jakarta.servlet.http.HttpCookie
Cookie是带有路径的,不同的cookie会带不同的路径,方便对应的提交信息和用于握手机制的实现
我们java的cookie主要是在response中将信息作为回传给浏览器的,在服务器中只是做一个信息的处理
在Http协议中规定如下,在浏览器发送请求时,会自动携带该路径下的cookie在请求头中给服务器
cookie的name和value都是字符串,cookie的name和value都是字符串
package com.bjpowernode.oa.action;
import com.bjpowernode.oa.Pojo.User;
import com.bjpowernode.oa.utils.DBUtil;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.*;
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
@WebServlet({"/user/login","/user/exit"})
public class UserServlet extends HttpServlet
{
//JSessionID=??这个键值对数据就是cookie保存的信息
//对于session关联的cookie来说,这个cookie是保存在浏览器的运行内存中的
//用户再次发送请求的时候,会自动把运行内存中的cookie放到请求头内一并发送
//服务器就是根据这个值找到对应的对象
//session存储在服务器上的,cookie是储存在电脑机器上的
//cookie可以存在浏览器运行内存中,也可以放在硬盘内保存
//cookie和session都是为了保存会话的状态
//这两个机制存在的目的就是为了解决我们的http协议的无状态无连接协议的问题
//(无状态无连接)没有请求和响应时,双方不知道对方是否还在
@Override
public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String servletPath = request.getServletPath();
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
if("/user/login".equals(servletPath))
{
doLogin(request,response);
}
else if("/user/exit".equals(servletPath))
{
doExit(request,response);
}
}
//将购物车中的商品编号放到cookie当中,cookie保存到硬盘
//下一次再打开,自动读取本地cookie,就还会显示这些商品
//购物网站未登录不允许查看商品和保存购物车的原理是,为了记录数据,什么用户喜欢什么样的东西
//和针对不同用户给出不同的优惠力度(大数据杀熟),并且可以防止爬虫,和减轻服务器压力(没有购买欲望的客户不让你看)
//十天免登录的实现原理如下,保存一个记录了用户名和密码的cookie到本地
//当十天内再次访问该网站时,会自动在请求头内发送这个账号用户名和密码到服务器,服务器接收到这个cookie
//解密后实现登录
//cookie和session都是Http协议的一部分,因为Http协议是无状态和无连接的协议
//Http协议规定,任何一个cookie都是由name和value组成的
//在java的servlet中,对cookie提供了那些支持?
//jakarta.servlet.http.HttpCookie
//Cookie是带有路径的,不同的cookie会带不同的路径,方便对应的提交信息和用于握手机制的实现
//我们java的cookie主要是在response中将信息作为回传给浏览器的,在服务器中只是做一个信息的处理
//在Http协议中规定如下,在浏览器发送请求时,会自动携带该路径下的cookie在请求头中给服务器
//cookie的name和value都是字符串,cookie的name和value都是字符串
private void doExit(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
HttpSession session = request.getSession(false);
if(session != null && session.getAttribute("user") != null)
{
//从session域中移除对象
session.removeAttribute("user");
//销毁session的方法,session.invalidate()
session.invalidate();
Cookie[] cookies = request.getCookies();
for (Cookie cookie : cookies)
{
cookie.setMaxAge(0);
cookie.setPath(request.getContextPath());
response.addCookie(cookie);
}
response.sendRedirect(request.getContextPath());
}
}
protected void doLogin(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
String username = request.getParameter("username");
String password = request.getParameter("password");
String loginSet = request.getParameter("flag");
Connection connection = null;
PreparedStatement statement = null;
ResultSet resultSet = null;
boolean flag = false;
try
{
connection = DBUtil.getConnection();
String sql = "select * from t_user where username = ? and pssword = ?";
statement = connection.prepareStatement(sql);
statement.setString(1,username);
statement.setString(2,password);
resultSet = statement.executeQuery();
if(resultSet.next())
{
flag = true;
}
}
catch (SQLException e)
{
throw new RuntimeException(e);
}
finally
{
DBUtil.close(connection,statement,resultSet);
}
if(flag)
{
HttpSession session = request.getSession();
session.setAttribute("user",new User(username,password));
if(loginSet != null && "1".equals(loginSet))
{
//存储登录名
Cookie name = new Cookie("username",username);
//存储密码
Cookie LoginPassword = new Cookie("password",password);
//生命周期都设为1小时,实验够了
name.setMaxAge(60 * 60);
LoginPassword.setMaxAge(60 * 60);
//保存到浏览器中
name.setPath(request.getContextPath());
LoginPassword.setPath(request.getContextPath());
//添加到响应中去
response.addCookie(name);
response.addCookie(LoginPassword);
}
response.sendRedirect(request.getContextPath() + "/dept/list");
}
else
{
response.sendRedirect(request.getContextPath() + "/Error.jsp");
}
}
}部门相关操作
package com.bjpowernode.oa.action;
import com.bjpowernode.oa.utils.DBUtil;
import com.bjpowernode.oa.Pojo.Dept;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
@WebServlet(urlPatterns = {"/dept/list","/dept/detail","/dept/delete","/dept/save","/dept/edit"})
public class DeptServlet extends HttpServlet
{
@Override
protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
String servletPath = request.getServletPath();
if("/dept/list".equals(servletPath))
{
doList(request,response);
}
else if("/dept/detail".equals(servletPath))
{
doDetail(request,response);
}
else if("/dept/delete".equals(servletPath))
{
doDel(request,response);
}
else if("/dept/save".equals(servletPath))
{
doSave(request,response);
}
else if("/dept/edit".equals(servletPath))
{
doModify(request,response);
}
}
private void doModify(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
Integer deptno = Integer.parseInt(request.getParameter("deptno"));
String dname = request.getParameter("dname");
String loc = request.getParameter("loc");
Connection connection = null;
PreparedStatement statement = null;
ResultSet resultSet = null;
int count = 0;
try
{
connection = DBUtil.getConnection();
connection.setAutoCommit(false);
String sql = "update dept set dname = ?,loc = ? where deptno = ?";
statement = connection.prepareStatement(sql);
statement.setString(1,dname);
statement.setString(2,loc);
statement.setInt(3,deptno);
count = statement.executeUpdate();
connection.commit();
}
catch (SQLException e)
{
if (connection != null)
{
try
{
connection.rollback();
}
catch (SQLException ex)
{
throw new RuntimeException(ex);
}
}
throw new RuntimeException(e);
}
finally
{
DBUtil.close(connection,statement,resultSet);
}
if(count == 1)
{
response.sendRedirect(request.getContextPath() + "/dept/list");
}
else
{
response.sendRedirect(request.getContextPath() + "/Error.jsp");
}
}
private void doSave(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
Integer deptno = Integer.parseInt(request.getParameter("deptno"));
String dname = request.getParameter("dname");
String loc = request.getParameter("loc");
Connection connection = null;
PreparedStatement statement = null;
ResultSet resultSet = null;
int count = 0;
try
{
connection = DBUtil.getConnection();
connection.setAutoCommit(false);
String sql = "insert into dept(deptno,dname,loc) values(?,?,?)";
statement = connection.prepareStatement(sql);
statement.setInt(1,deptno);
statement.setString(2,dname);
statement.setString(3,loc);
count = statement.executeUpdate();
connection.commit();
}
catch (SQLException e)
{
if (connection != null)
{
try
{
connection.rollback();
}
catch (SQLException ex)
{
throw new RuntimeException(ex);
}
}
throw new RuntimeException(e);
}
finally
{
DBUtil.close(connection,statement,resultSet);
}
if(count == 1)
{
response.sendRedirect(request.getContextPath() + "/dept/list");
}
else
{
response.sendRedirect(request.getContextPath() + "/Error.jsp");
}
}
private void doDel(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
Connection connection = null;
PreparedStatement statement = null;
ResultSet resultSet = null;
String deptno = request.getParameter("deptno");
int count = 0;
try
{
connection = DBUtil.getConnection();
connection.setAutoCommit(false);
String sql = "delete from dept where deptno = ?";
statement = connection.prepareStatement(sql);
statement.setString(1,deptno);
count = statement.executeUpdate();
connection.commit();
}
catch (SQLException e)
{
if (connection != null)
{
try
{
connection.rollback();
}
catch (SQLException ex)
{
throw new RuntimeException(ex);
}
}
throw new RuntimeException(e);
}
finally
{
DBUtil.close(connection,statement,resultSet);
}
if(count == 1)
{
response.sendRedirect(request.getContextPath() + "/dept/list");
}
else
{
response.sendRedirect(request.getContextPath() + "/Error.jsp");
}
}
private void doDetail(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
Connection connection = null;
PreparedStatement statement = null;
ResultSet resultSet = null;
String deptno = request.getParameter("deptno");
try
{
connection = DBUtil.getConnection();
String sql = "select * from dept where deptno = ?";
statement = connection.prepareStatement(sql);
statement.setString(1,deptno);
resultSet = statement.executeQuery();
if(resultSet.next())
{
String dname = resultSet.getString("dname");
String loc = resultSet.getString("loc");
Dept dept = new Dept(deptno,dname,loc);
request.setAttribute("dept",dept);
}
}
catch (SQLException e)
{
throw new RuntimeException(e);
}
finally
{
DBUtil.close(connection,statement,resultSet);
}
String flag = request.getParameter("f");
if("d".equals(flag))
{
request.getRequestDispatcher("/detail.jsp").forward(request,response);
}
if("m".equals(flag))
{
request.getRequestDispatcher("/edit.jsp").forward(request,response);
}
}
private void doList(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
//连接数据库,查询所有部门信息
Connection connection = null;
PreparedStatement statement = null;
ResultSet resultSet = null;
List<Dept> list = new ArrayList<Dept>();
try
{
connection = DBUtil.getConnection();
String sql = "select * from dept";
statement = connection.prepareStatement(sql);
resultSet = statement.executeQuery();
while(resultSet.next())
{
String deptno = resultSet.getString("deptno");
String dname = resultSet.getString("dname");
String loc = resultSet.getString("loc");
Dept dept = new Dept(deptno,dname,loc);
list.add(dept);
}
request.setAttribute("depts",list);
request.getRequestDispatcher("/list.jsp").forward(request,response);
}
catch (SQLException e)
{
throw new RuntimeException(e);
}
finally
{
DBUtil.close(connection,statement,resultSet);
}
}
}