项目搭建
- 项目链接https://gitee.com/zhangjzm/smbms.git
- 前置知识，Servlet JSP
结构图
搭建maven web项目
1.搭建一个maven web项目
2.配置tomcat
3.测试项目是否能跑起来
4.导入项目中遇到的jar包
- jsp，servlet，mysql驱动，jstl，standard
5.创建项目包结构
6.编写实体类
- ORM映射：表-类映射
7.编写基础公共类
- 1）数据库配置文件
- 2)编写数据库的公共类
------四部曲，1.使用Properties（IO流）获取连接数据 2.进行连接 3.执行体（ResultSet或int） 4.关闭流
Properties对象类似Key Value取值
InputStream inputStream = BaseDao.class.getClassLoader().getResourceAsStream("db.properties");
类加载器 .class.getClassLoader().getResourceAsStream取值
properties.load(inputStream);//IO流取值
本质----------------获取数据库数据
- 答：1.从引入dao来说，如果你直接由controller来进行，那么DAO发生替换（比如从oracle迁移mysql），需要找到所有controller里的调用点，逐一修改。
- 2.如果每个判别，操作都由controller来进行，那么同层的controller并不能互通（处理数据），比如：折扣计算，反作弊判定
package com.zjz.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
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();
}
return connection;
}
//编写查询公共类
public static ResultSet execute(Connection connection,String sql,Object[] params,ResultSet resultSet, PreparedStatement preparedStatement) throws SQLException {
preparedStatement = connection.prepareStatement(sql);
int len = params.length;
for(int i = 0;i<len;i++){
//setObject 占位符从1开始，数组是从0开始
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,String sql,Object[] params, PreparedStatement preparedStatement) throws SQLException {
preparedStatement = connection.prepareStatement(sql);
int len = params.length;
for(int i = 0;i<len;i++){
//setObject 占位符从1开始，数组是从0开始
preparedStatement.setObject(i+1,params[i]);
}
int updateRows = preparedStatement.executeUpdate();
return updateRows;
}
//释放资源
public static boolean closeResource(Connection connection,ResultSet resultSet, PreparedStatement preparedStatement){
boolean flag = true;
if(resultSet!=null){
try {
resultSet.close();
//GC回收
resultSet = null;
} catch (SQLException throwables) {
throwables.printStackTrace();
flag = false;
}
}
if(connection!=null){
try {
connection.close();
//GC回收
connection = null;
} catch (SQLException throwables) {
throwables.printStackTrace();
flag = false;
}
}
if(preparedStatement!=null){
try {
preparedStatement.close();
//GC回收
preparedStatement = null;
} catch (SQLException throwables) {
throwables.printStackTrace();
flag = false;
}
}
return flag;
}
}
- 8.编写字符编码过滤器
- Filter类
- web配置
功能一 登录功能的实现
编写
- 1.编写前端
- 2.设置首页，web.xml
<!--设置欢迎页面-->
<welcome-file-list>
<welcome-file>/login.jsp</welcome-file>
</welcome-file-list>
- 3.编写dao层，用户登录的接口
public interface UserDao {
//得到要登录的用户
public User getLoginUser(Connection connection,String userCode) throws SQLException;
}
- 4.编写dao接口实现类
public class UserDaoImpl implements UserDao{
public User getLoginUser(Connection connection, String userCode) throws SQLException {
PreparedStatement pstm = null;
ResultSet rs = null;
User user = null;
if(connection != null){
String sql = "select * from smbms_user where userCode = ?";
Object[] params = {userCode};
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;
}
}
- 5.业务层接口
public interface UserService { //用户登录 public User login(String userCode, String password); } - 6.业务层实现类
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();
}
public User login(String userCode, String password) {
Connection connection = null;
User user = null;
try {
connection = BaseDao.getConnection();
//通过业务层调用具体的数据库操作
user = userDao.getLoginUser(connection,userCode);
} catch (SQLException throwables) {
throwables.printStackTrace();
}finally {
BaseDao.closeResource(connection,null,null);
}
return user;
}
@Test
public void test(){
UserServiceImpl userService = new UserServiceImpl();
User wen = userService.login("wen", "123");
System.out.println("密码为：" + wen.getUserPassword());
}
}
- 7.servlet层实现
public class LoginServlet extends HttpServlet {
//Servlet:控制层，调用业务层代码
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
System.out.println("LoginServlet---start");
//获取用户的用户名和密码
String userCode = req.getParameter("userCode");
String userPassword = req.getParameter("userPassword");
//和用户数据库中的密码对比，调用业务层
UserService userService = new UserServiceImpl();
User user = userService.login(userCode, userPassword);//登录的人查出来
if(user != null&&(user.getUserPassword().equals(userPassword))){//查到有这个人
//将用户的信息放到session中
req.getSession().setAttribute(Constants.USER_SESSION,user);
//跳转到主页
resp.sendRedirect("jsp/frame.jsp");
}else {//查无此人
//转发回登录页面，并提示错误
req.setAttribute("error","用户名，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);
}
}
- 8.注册servle
<servlet>
<servlet-name>LoginServlet</servlet-name>
<servlet-class>com.zjz.servlet.user.LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/login.do</url-pattern>
</servlet-mapping>
- 9.编写过滤器，拦截没登录的
public class SysFilter implements Filter {
public void init(FilterConfig filterConfig) throws ServletException {
}
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest) servletRequest;
HttpServletResponse response = (HttpServletResponse)servletResponse;
//从session中获取用户
User user = (User) request.getSession().getAttribute(Constants.USER_SESSION);
if(user==null){//说明已经注销了
response.sendRedirect("/error.jsp");
}else {
filterChain.doFilter(servletRequest,servletResponse);
}
}
public void destroy() {
}
}
<!--用户登录过滤器-->
<filter>
<filter-name>SysFilter</filter-name>
<filter-class>com.zjz.Filter.SysFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>SysFilter</filter-name>
<url-pattern>/jsp/*</url-pattern>
</filter-mapping>
- 10.由底层向上层写
功能二，修改密码-修当前的
编写
- 设置文本类型
resp.setContentType("application/json"); // setContentType 设置文本的类型
功能三，用户界面
编写
- 总体思路，用户展示
List<User> userList = userService.getUserList(queryUserName, queryUserRole, currentPageNo, pageSize);- 总数量--返回一个总数量
- 分页Bean 专用于分页。。也就是一个服务类，利用总数量服务currentPageNo动态变化
1.导入分页的工具类
2.用户列表的导入
- userlist.jsp
1.获取用户数量
- UserDao UserDaoImpl UserService UserServiceImpl
2.分页的逻辑
- 在数据库中分页使用 Limit startIndex，pageSize; 总数
- 0,5--第1页-- 6,5--第2页-- 11,5--第3页----每页五个
- 当前页 （当前页-1） * 页面大小
3.获取用户列表
- userdao
public List<User> getUserList(Connection connection,String username,int userRole,int currentPageNo,int pageSize)throws Exception;- userdaoImpl UserService UserServiceImpl
4.用户显示的servlet
- 1.获取用户前端的数据（查询）
- 2.判断请求是否需要执行，看参数的值判断
- 3.为了实现分页，需要计算当前页面的总页面，以及页面大小
- 4.用户前端展示
- 5.返回前端
-------- 更多学习 https://zhangjzm.gitee.io/self_study