1.搭建一个maven web项目

2.配置Tomcat

3.测试项目是否能够跑起来

4.导入项目中会遇到的Jar包

jsp，servlet，mysql驱动，jstl，standard

5.项目结构搭建

6.项目实体类搭建

ORM映射表---类映射

7.编写基础公共类

1.数据库配置文件

db.properties

driver=com.mysql.jdbc.Driver
url=jdbc:mysql//localhost:3306?useUnicode=true&character=utf-8
username=root
password=2001

2.编写数据库的公共类

package com.kuang.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 username;
    private static String password;
    private static String url;

    //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  等价于  Class.forName()也是一个类加载器，但这个类加载器是加载配置文件的，把配置文件放入输入流中。
        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;
    }

    //编写查询公共方法
    public static ResultSet execute(Connection connection, String sql, Object[] param, PreparedStatement preparedStatement,ResultSet resultSet){
        try {
            preparedStatement = connection.prepareStatement(sql);
            for (int i = 0; i <param.length ; i++) {
                preparedStatement.setObject(i+1,param[i]);
            }
            resultSet = preparedStatement.executeQuery();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return  resultSet;

    }
    //编写增删改公共方法
    public static int execute(Connection connection, String sql, Object[] param, PreparedStatement preparedStatement) throws SQLException {

            preparedStatement = connection.prepareStatement(sql);
            for (int i = 0; i <param.length ; i++) {
                preparedStatement.setObject(i+1,param[i]);
            }
            int updateRows = preparedStatement.executeUpdate();

        return  updateRows;

    }

    //关闭方法
    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();
                preparedStatement=null;
            } catch (SQLException e) {
                e.printStackTrace();
                flag=false;
            }
        }
        if (connection!=null){
            try {
                connection.close();
                connection=null;
            } catch (SQLException e) {
                e.printStackTrace();
                flag=false;
            }
        }
        return flag;
    }


}

3.编写字符编码过滤器

package com.kuang.filter;

import javax.servlet.*;
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("utf-8");
                 servletResponse.setCharacterEncoding("utf-8");
                 filterChain.doFilter(servletRequest,servletResponse);

    }

    @Override
    public void destroy() {

    }
}

3.1web配置注册

 <filter>
        <filter-name>CharacterEncodingFilter</filter-name>
        <filter-class>com.kuang.filter.CharacterEncodingFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>CharacterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>