SMBMS项目
项目架构
项目数据库
项目文件目录
项目搭建准备工作
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
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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
-
编写公共基础类
(1)数据库配置文件(放在resources目录下的db.resources文件)
(2)编写数据库公共类
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
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资源
InputStream is = BaseDao.class.getClassLoader().getResourceAsStream("db.properties");
try {
properties.load(is);
} catch (Exception e) {
e.printStackTrace();
}
driver=properties.getProperty("driver");
url=properties.getProperty("url");
username=properties.getProperty("username");
password=properties.getProperty("password");
}
//获取数据库的链接
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);
for (int i = 0; i < params.length; i++) {
//setObject,占位符从1开始
preparedStatement.setObject(i+1,params);
}
//此处不需要再传入sql参数,已经预编译
resultSet = preparedStatement.executeQuery();
return resultSet;
}
//编写增删改的公共方法
public static int execute(Connection connection,String sql,Object[] params,PreparedStatement preparedStatement) throws SQLException {
preparedStatement = connection.prepareStatement(sql);
for (int i = 0; i < params.length; i++) {
//setObject,占位符从1开始
preparedStatement.setObject(i+1,params);
}
//此处不需要再传入sql参数,已经预编译
int updateRows = preparedStatement.executeUpdate();
return updateRows;
}
//释放资源,关闭连接
public static boolean closeResource(Connection connection,PreparedStatement preparedStatement,ResultSet resultSet){
boolean flag=true;
if(resultSet!=null){
try {
resultSet.close();
//GC回收,防止关闭后仍不为null
resultSet=null;
} catch (SQLException e) {
e.printStackTrace();
flag=false;
}
}
if(preparedStatement!=null){
try {
preparedStatement.close();
//GC回收,防止关闭后仍不为null
preparedStatement=null;
} catch (SQLException e) {
e.printStackTrace();
flag=false;
}
}
if(connection!=null){
try {
connection.close();
//GC回收,防止关闭后仍不为null
connection=null;
} catch (SQLException e) {
e.printStackTrace();
flag=false;
}
}
return flag;
}
}
(3)编写字符编码过滤器(编写完后记得在web.xml中进行过滤器注册)
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 java.io.IOException;
public class CharacterEncodingFilter implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
servletRequest.setCharacterEncoding("utf8");
servletResponse.setCharacterEncoding("utf8");
filterChain.doFilter(servletRequest,servletResponse);
}
@Override
public void destroy() {
}
}
8.导入静态资源(js,css等)
登录功能实现
登录功能结构
- 编写前端页面(可以通过网上搜索smbms或超市订单管理系统下载他人前端页面:github地址)要注意因为项目文件目录和文件名的不同,根据自己项目调整程序代码。
- 设置首页(login.jsp)
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8" isELIgnored="false" %>
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title>系统登录 - 超市订单管理系统</title>
<%--注意这里css路径href使用绝对路径,否则加载不出来css页面--%>
<link type="text/css" rel="stylesheet" href="css/style.css" />
<script type="text/javascript">
/* if(top.location!=self.location){
top.location=self.location;
} */
</script>
</head>
<body class="login_bg">
<section class="loginBox">
<header class="loginHeader">
<h1>超市订单管理系统</h1>
</header>
<section class="loginCont">
<form class="loginForm" action="${pageContext.request.contextPath}/login.do" name="actionForm" id="actionForm" method="post" >
<div class="info">${error }</div>
<div class="inputbox">
<label for="userCode">用户名:</label>
<input type="text" class="input-text" id="userCode" name="userCode" placeholder="请输入用户名" required/>
</div>
<div class="inputbox">
<label for="userPassword">密码:</label>
<input type="password" id="userPassword" name="userPassword" placeholder="请输入密码" required/>
</div>
<div class="subBtn">
<input type="submit" value="登录"/>
<input type="reset" value="重置"/>
</div>
</form>
</section>
</section>
</body>
</html>
<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
//面向接口编程
public interface UserDao {
//得到要登录的用户
public User getLoginUser(Connection connection,String userCode) throws SQLException;
}
- 根据登录接口编写实现类
public class UserDaoImpl extends HttpServlet implements UserDao{
@Override
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, sql, params, rs, pstm);
if (rs.next()){
user = new User();
user.setId(rs.getLong("id"));
user.setUserCode(rs.getString("userCode"));
user.setUserName(rs.getString("userName"));
user.setUserPassword(rs.getString("userPassword"));
user.setGender(rs