package org.example.utils;
import java.sql.*;
public class JavaDateConnection {
    /**
     * 获取数据库连接
     * @return Connection
     */
    public  Connection getConn() {
    //project为数据库名
        String url = "jdbc:mysql://localhost:3306/project";
        //用户名
        String username = "root";
        //密码
        String password = "Hyk59308";
        Connection conn = null;
        try {
        //注册驱动
            Class.forName("com.mysql.jdbc.Driver");
            //classLoader,加载对应驱动
            conn = DriverManager.getConnection(url, username, password);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return conn;
    }

String sql1="insert into myTable values(?,?,?,?)";//定义sql语句
    String sql2="select * from myTable";              //定义sql语句
    int result=0;             //修改操作的返回值是一个整数，即受影响的行数
``/**
       * PreparedStatement继承自Statement接口,PreparedStatement的对象已预编译过，
       * 执行速度快于Statement对象,创建其对象时，需要SQL命令字符串作为对象
       */
      PreparedStatement ps=connection.prepareStatement(sql1);           
      ps.setString(1,"tanker");
      ps.setString(2, "m");
      ps.setString(3,"1991-11-20");
      ps.setString(4, "Franch");
      result=ps.executeUpdate();
      if(result>0)
        System.out.println("插入成功");
      else
        System.out.println("插入失败");
      //Statement用于将sql语句发送到数据库
      Statement statement=connection.createStatement();
      //执行数据库操作返回的结果集,其定义的是数据库游标
      ResultSet results=statement.executeQuery(sql2);  
      System.out.println("name"+" "+"sex"+" "+"birth"+" "+"birthaddr");
      System.out.println("------------------------");
      while(results.next())
      {
        System.out.println(results.getString("name")+" "+
                     results.getString("sex")+" "+
                     results.getString("birth")+" "+
                     results.getString("birthaddr"));
      }
      System.out.println("搞定！");

     * 关闭Connection PreparedStatement
     * @param connection
     * @param preparedStatement
     */
    public static void closeConnection(Connection connection, PreparedStatement preparedStatement, ResultSet resultSet){
        if (resultSet != null) {
            try {
                resultSet.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (preparedStatement != null) {
            try {
                preparedStatement.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        if (connection != null) {
            try {
                connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

package util;
import com.alibaba.druid.pool.DruidDataSourceFactory;
import javax.sql.DataSource;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
public class DBUtil {
    private static DataSource ds;
    static {
        //1.加载配置文件
        Properties pro = new Properties();
        try {
            pro.load(DBUtil.class.getClassLoader().getResourceAsStream("/db.properties"));
            //获取DataSource
            ds = DruidDataSourceFactory.createDataSource(pro);
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    //获取连接
    public static Connection getConnection() throws SQLException {
        return ds.getConnection();
    }

/**
     * @param sql SQL语句
     * @param objs  SQL语句占位符实参，如果没有参数则传入null
     * @return 返回增删改的结果，类型为int
     */
    public static int executeDML(String sql,Object...objs){
        // 声明jdbc变量
        Connection conn = null;
        PreparedStatement ps = null;
        int i = -1;
        try {
            // 获取连接对象
            conn = DBUtil.getConnection();
            // 开启事务管理
            conn.setAutoCommit(false);
            // 创建SQL命令对象
            ps = conn.prepareStatement(sql);
            // 给占位符赋值
            if(objs!=null){
                for(int j=0;j<objs.length;j++){
                    ps.setObject(j+1,objs[j]);
                }
            }
            // 执行SQL
            i = ps.executeUpdate();
            conn.commit();
        } catch (Exception e) {
            try {
                conn.rollback();
            } catch (SQLException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }
            e.printStackTrace();
        } finally {
            DBUtil.closeAll(null, ps, conn);
        }
        return i;
    }

 //关闭资源
    public static void closeAll(ResultSet rs,Statement stmt,Connection conn){
        try {
            if(rs!=null){
                rs.close();
            }
        } catch (SQLException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }
        try {
            stmt.close();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        try {
            conn.close();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }