搭建一个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 stand
创建项目包结构
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.jdbc.Driver
url=jdbc:mysql://localhost:3306?useUnicode=true&characterEncoding=utf-8
username=root
password=root
编写数据库的公共类
package com.yang.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 {
//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++) {
preparedStatement.setObject(i+1,params[i]);
}
resultSet = preparedStatement.executeQuery(sql);
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);
for (int i = 0; i < params.length; i++) {
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;
}
}
编写字符编码过滤器
导入静态资源
原文:https://www.cnblogs.com/y6ming/p/13678584.html