标签：update Servle tomcat new request -- jar OLE 搭建
数据库：
使用Maven
搭配一个maven web项目
配置Tomcat
测试项目是否能够跑起来
导入项目中会遇到的jar包
jsp, Servlet, mysql驱动, jstl, standard...
创建包结构
编写实体类
ORM映射：表-类映射
编写基础公共类
数据库配置文件
driver=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/smbms?useSSL=true&useUnicode=true&characterEncoding=utf-8
username=root
password=123456编写数据库公共类
package com.hitenine.dao;
import java.io.IOException;
import java.io.InputStream;
import java.sql.*;
import java.util.Properties;
//操作数据库的公共类
public class BaseDao {
private static String driver;
private static String url;
private static String username;
private static String password;
//静态代码块，类加载的时候就初始化了
static {
Properties properties = new Properties();
//通过类加载器读取对应的资源
InputStream is = BaseDao.class.getClassLoader().getResourceAsStream("db.properties");
try {
properties.load(is);
} catch (IOException e) {
e.printStackTrace();
}
driver = properties.getProperty("driver");
url = properties.getProperty("url");
username = properties.getProperty("username");
password = properties.getProperty("password");
}
//获取数据库的连接
public static Connection getConnection() {
Connection connection = null;
try {
Class.forName(driver);
connection = DriverManager.getConnection(url, username, password);
} catch (Exception e) {
e.printStackTrace();
}
System.out.println("ok");
return connection;
}
/*
有些bug
*/
//编写查询公共方法
public static ResultSet execute(Connection connection, PreparedStatement preparedStatement, ResultSet resultSet, String sql, Object[] params) throws SQLException {
//预编译的sql，在后面直接执行就可以了
preparedStatement = connection.prepareStatement(sql);
for (int i = 0; i < params.length; i++) {
//setObject，占据符从1开始，但是我们的数组是从0开始的
preparedStatement.setObject(i + 1, params[i]);
}
resultSet = preparedStatement.executeQuery();
return resultSet;
}
//编写增删改公共方法
public static int execute(Connection connection, PreparedStatement preparedStatement, String sql, Object[] params) throws SQLException {
//预编译的sql，在后面直接执行就可以了
preparedStatement = connection.prepareStatement(sql);
for (int i = 0; i < params.length; i++) {
//setObject，占据符从1开始，但是我们的数组是从0开始的
preparedStatement.setObject(i + 1, params[i]);
}
int updateRows = preparedStatement.executeUpdate();
return updateRows;
}
//释放资源
public static boolean closeResource(Connection connection, PreparedStatement preparedStatement, ResultSet resultSet) {
boolean flag = true;
if (null != resultSet) {
try {
resultSet.close();
//GC回收
resultSet = null;
} catch (SQLException e) {
e.printStackTrace();
flag = false;
}
}
if (null != preparedStatement) {
try {
preparedStatement.close();
//GC回收
preparedStatement = null;
} catch (SQLException e) {
e.printStackTrace();
flag = false;
}
}
if (null != connection) {
try {
connection.close();
//GC回收
connection = null;
} catch (SQLException e) {
e.printStackTrace();
flag = false;
}
}
return flag;
}
}编写字符编码过滤器
导入静态资源
编写前端页面
设置首页
<!--设置首页-->
<welcome-file-list>
<welcome-file>login.jsp</welcome-file>
</welcome-file-list>编写dao层登录用户登录的接口
//得到要登录的用户
public User getLoginUser(Connection connection, String userCode) throws SQLException;
编写dao接口的实现类
package com.hitenine.dao.user;
import com.hitenine.dao.BaseDao;
import com.hitenine.pojo.User;
import javax.servlet.http.HttpServlet;
import java.sql.*;
public class UserDaoImpl extends HttpServlet implements UserDao{
//得到要登录的用户
@Override
public User getLoginUser(Connection connection, String userCode) throws SQLException {
PreparedStatement pstm = null;
ResultSet rs = null;
User user = null;
if (null != connection) {
String sql = "select * from smbms_user where userCode=?";
Object[] params = {userCode};
Statement statement = connection.createStatement();
rs = BaseDao.execute(connection, pstm, rs, sql, params);
if (rs.next()) {
user = new User();
user.setId(rs.getInt("id"));
user.setUserCode(rs.getString("userCode"));
user.setUserName(rs.getString("userName"));
user.setUserPassword(rs.getString("userPassword"));
user.setGender(rs.getInt("gender"));
user.setBirthday(rs.getDate("birthday"));
user.setPhone(rs.getString("phone"));
user.setAddress(rs.getString("address"));
user.setUserRole(rs.getInt("userRole"));
user.setCreatedBy(rs.getInt("createdBy"));
user.setCreationDate(rs.getTimestamp("creationDate"));
user.setModifyBy(rs.getInt("modifyBy"));
user.setModifyDate(rs.getTimestamp("modifyDate"));
}
BaseDao.closeResource(null, pstm, rs);
}
return user;
}
}业务层接口
//用户登录
public User login(String userCode, String password);业务层实现类
package com.hitenine.service.user;
import com.hitenine.dao.BaseDao;
import com.hitenine.dao.user.UserDao;
import com.hitenine.dao.user.UserDaoImpl;
import com.hitenine.pojo.User;
import java.sql.Connection;
import java.sql.SQLException;
public class UserServiceImpl implements UserService {
//业务层都会调用dao层，所以我们要引入Dao层
private UserDao userDao;
public UserServiceImpl() {
userDao = new UserDaoImpl();
}
@Override
public User login(String userCode, String password) {
Connection connection = null;
User user = null;
try {
connection = BaseDao.getConnection();
//通过业务层调用对应的数据库操作
user = userDao.getLoginUser(connection, userCode);
} catch (SQLException e) {
e.printStackTrace();
} finally {
BaseDao.closeResource(connection, null, null);
}
return user;
}
编写Servlet
package com.hitenine.servlet.user;
import com.hitenine.pojo.User;
import com.hitenine.service.user.UserServiceImpl;
import com.hitenine.util.Constants;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
public class LoginServlet extends HttpServlet {
//Servlet:控制层，调用业务层
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
System.out.println("LoginServlet---start---");
//获取用户名和密码
String userCode = req.getParameter("userCode");
String userPassword = req.getParameter("userPassword");
//和数据库中的密码进行对比，调用业务层
UserServiceImpl userService = new UserServiceImpl();
User user = userService.login(userCode, userPassword); //这里已经把登录的人给查出来了
//判断语句加上user.getUserPassword().equals(userPassword)，为了便于测试暂不加
if (null != user) { //查有此人，可以登录
//将用户的信息放到Session中
req.getSession().setAttribute(Constants.USER_SESSION, user);
//跳转到内部主页
resp.sendRedirect("jsp/frame.jsp");
} else { //查无此人，无法登录
//转发会登陆页面，顺带提示用户名或者密码错误
req.setAttribute("error", "用户名或者密码不正确");
req.getRequestDispatcher("login.jsp").forward(req, resp);
}
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doGet(req, resp);
}
}注册Servlet
<!--Servlet-->
<servlet>
<servlet-name>LoginServlet</servlet-name>
<servlet-class>com.hitenine.servlet.user.LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/login.do</url-pattern>
</servlet-mapping>测试访问，确保以上功能成功！
思路：移除Session，返回登陆页面
package com.hitenine.servlet.user;
import com.hitenine.util.Constants;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
public class LogoutServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//移除用户的Constants.USER_SESSION
req.getSession().removeAttribute(Constants.USER_SESSION);
resp.sendRedirect(req.getContextPath() + "/login.jsp"); //返回登录页面
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doGet(req, resp);
}
}注册xml
<servlet>
<servlet-name>LogoutServlet</servlet-name>
<servlet-class>com.hitenine.servlet.user.LogoutServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LogoutServlet</servlet-name>
<url-pattern>/jsp/logout.do</url-pattern>
</servlet-mapping>package com.hitenine.filter;
import com.hitenine.pojo.User;
import com.hitenine.util.Constants;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
public class SysFilter implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
HttpServletRequest req = (HttpServletRequest) request;
HttpServletResponse resp = (HttpServletResponse) response;
User user = (User) req.getSession().getAttribute(Constants.USER_SESSION);
if (null == user) { //已经被移除或者注销了，或者未登录
resp.sendRedirect("/smbms/error.jsp");
} else {
chain.doFilter(request, response);
}
}
@Override
public void destroy() {
}
}注册xml
<!--用户登录过滤器-->
<filter>
<filter-name>SysFilter</filter-name>
<filter-class>com.hitenine.filter.SysFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>SysFilter</filter-name>
<url-pattern>/jsp/*</url-pattern>
</filter-mapping>标签：update Servle tomcat new request -- jar OLE 搭建
原文地址：https://www.cnblogs.com/hitenine/p/12183074.html
