SMBMS超市管理系统
SMBMS超市管理系统架构
数据库
项目如何搭建?
考虑使不使用Maven?依赖,Jar
项目搭建:
1.搭建一个maven web项目
2.配置Tomcat
3.测试项目能够跑起来
4.导入项目遇到的Jar包
jsp,servlet,mysql驱动,jstl,stand...
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
db.propertiles
driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306?useUnicode=true&characterEncoding=utf-8
username=root
password=123456
2.编写数据库的公共类
package com.jiang.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.propertiles");
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");
}
//获取数据库连接
public static Connection getConnectio(){
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,但是数组是从0开始
preparedStatement.setObject(i+1,params[i]);
}
resultSet = preparedStatement.executeQuery(sql);
return resultSet;
}
//编写增删改工具类
public static int execute(Connection connection,String sql,Object[] params,PreparedStatement preparedStatement) 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 占位符从1开始,但是数组是从0开始
preparedStatement.setObject(i+1,params[i]);
}
int updateRows = preparedStatement.executeUpdate(sql);
return updateRows;
}
//释放资源
public static boolean closeResource(Connection connection,PreparedStatement preparedStatement,ResultSet resultSet){
boolean flag=true;
if(resultSet!=null){
try {
resultSet.close();
//GC回收
resultSet=null;
} catch (SQLException e) {
e.printStackTrace();
flag=false;
}
}
if(preparedStatement!=null){
try {
preparedStatement.close();
//GC回收
preparedStatement=null;
} catch (SQLException e) {
e.printStackTrace();
flag=false;
}
}
if(connection!=null){
try {
connection.close();
//GC回收
connection=null;
} catch (SQLException e) {
e.printStackTrace();
flag=false;
}
}
return flag;
}
}
3.编写字符编码过滤器
package com.jiang.filter;
import javax.servlet.*;
import java.io.IOException;
//编码过滤器
public class CharacterEncodingFilter implements Filter {
public void init(FilterConfig filterConfig) throws ServletException {
}
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
servletRequest.setCharacterEncoding("utf-8");
servletResponse.setCharacterEncoding("utf-8");
filterChain.doFilter(servletRequest,servletResponse);//继续往下放行
}
public void destroy() {
}
}
8.导入静态资源