2020.03.23 idea中數據庫的連接

package com.guoyun.utils;

import java.sql.*;

/**
 * ClassName:
 * Function:  ADD FUNCTION
 * Reason:   ADD REASON
 *
 * @author
 * @Date
 * @since Ver 1.1
 */
public class DBUtils {
    //連接對象
    public Connection conn;
    //狀態對象
    public Statement state;
    //結果集合對象
    public ResultSet rs;

//獲得數據庫的連接
    public Connection getConnection(){
        try {
            //連接sqlserver
                //Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
            Class.forName("com.mysql.jdbc.Driver");
            conn= DriverManager.getConnection("jdbc:mysql://localhost:3306/student","root" ,"123");
        } catch (Exception e) {
            e.printStackTrace();
        }
            return conn;
    }
    //獲得數據庫狀態對象
    public Statement getStatement(){
        try {
            state=getConnection().createStatement();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return  state;
    }

    //執行查詢sql語句的方法
    public ResultSet query(String sql){
        try {
            rs=getStatement().executeQuery(sql);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return rs;
    }
    //執行dml語言
    public int update(String sql){
        int result=-1;
        try {
            result=getStatement().executeUpdate(sql);
        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            closeDB();
        }
        return result;
    }
    //關閉狀態對象 關閉數據庫連接
    public void closeDB(){
        try {
            if(rs!=null){
                rs.close();
            }
            if(state!=null){
                state.close();
            }
            if(conn!=null){
                conn.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}