Java数据库

package com.wang.lesson02;

import com.wang.lesson02.utils.JdbcUtils;

import java.sql.*;

import java.util.Date;



public class TestPrepareStatement {

    public static void main(String[] args) {
        Connection conn = null;
        PreparedStatement pst = null;
        ResultSet rs = null;
        //PreparedStatement 能够解决sql注入问题
        

        try {
            conn = JdbcUtils.getConnection();//获取数据库连接
            //区别， 使用 ？ 占位符代替参数
            String sql = "insert into users (id,Name,PASSWORD,email,birthday) "+
                    "values(?,?,?,?,?);";//sql语句

            //预编译
            pst = conn.prepareStatement(sql);

            //实现原理，将输入的字符串整体看作一个字符串，’符号会被直接转义，即可避免sql注入
            pst.setInt(1,5);
            pst.setString(2,"sb");
            pst.setString(3,"123456");
            pst.setString(4,"836717172@qq.com");
            pst.setDate(5,new java.sql.Date(new Date().getTime()));

            int i = pst.executeUpdate();

            if(i>0) System.out.println("插入成功...");

        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }finally {
            JdbcUtils.release(conn,pst,rs);
        }

    }


}

package com.wang.lesson02.utils;

import java.io.InputStream;
import java.sql.*;
import java.util.Properties;



public class JdbcUtils {

    private static String driver = null;
    private static String url = null;
    private static String username = null;
    private static String password = null;
    //静态代码块来实现加载mysql驱动
    static {
        try{
            //db.properties里的信息被读取出来了
            InputStream in = JdbcUtils.class.getClassLoader().getResourceAsStream("db.properties");
            Properties properties = new Properties();
            properties.load(in);

            driver = properties.getProperty("driver");
            url = properties.getProperty("url");
            username = properties.getProperty("username");
            password = properties.getProperty("password");

            //驱动只用加载一次
            Class.forName(driver);

        } catch (Exception e) {
            e.printStackTrace();
        }
    }


    //获取连接
    public static Connection getConnection() throws SQLException {
            return DriverManager.getConnection(url,username,password);
    }


    //释放连接资源
    public static void release(Connection con, Statement st, ResultSet rs){
        if (rs!=null){
            try {
                rs.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }

        if(st!=null){
            try {
                st.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }

        if(con!=null){
            try {
                con.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
    }


}

driver = com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/jdbcstudy?useUnicode=true&characterEncoding=utf8&useSSL=true
username = root
password = root