2020.03.23 idea中数据库的连接

package com.guoyun.utils;

import java.sql.*;

/**
 * ClassName:
 * Function:  ADD FUNCTION
 * Reason:   ADD REASON
 *
 * @author
 * @Date
 * @since Ver 1.1
 */
public class DBUtils {
    //连接对象
    public Connection conn;
    //状态对象
    public Statement state;
    //结果集合对象
    public ResultSet rs;

//获得数据库的连接
    public Connection getConnection(){
        try {
            //连接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;
    }
    //获得数据库状态对象
    public Statement getStatement(){
        try {
            state=getConnection().createStatement();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return  state;
    }

    //执行查询sql语句的方法
    public ResultSet query(String sql){
        try {
            rs=getStatement().executeQuery(sql);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return rs;
    }
    //执行dml语言
    public int update(String sql){
        int result=-1;
        try {
            result=getStatement().executeUpdate(sql);
        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            closeDB();
        }
        return result;
    }
    //关闭状态对象 关闭数据库连接
    public void closeDB(){
        try {
            if(rs!=null){
                rs.close();
            }
            if(state!=null){
                state.close();
            }
            if(conn!=null){
                conn.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}