DBUtil

1.先创建两个JAVA class文件， 命名为DBUtil和test3

写DBUtil
package com.gongmao;
import java.sql.*;

public class DBUtil {
public static Connection getConnection() throws ClassNotFoundException,SQLException{
Class.forName(“com.mysql.jdbc.Driver”);
Connection connection = DriverManager.getConnection(“jdbc:mysql://127.0.0.1:3306/zjgm?characterEncoding=utf-8&user=root&password=123456&useSSL=false”);
return connection;
}
public static void closeAll(ResultSet resultSet, Statement statement,Connection connection) throws SQLException{
if(resultSet!=null){
resultSet.close();
}
statement.close();
connection.close();
}
}
2.写好DBUtil后在昨天原有代码基础上替换，替换后的代码为

package com.gongmao;

import java.sql.*;

public class test {
public static void main(String[] args) throws ClassNotFoundException, SQLException {
DBUtil dbUtil=new DBUtil();
Connection connection=dbUtil.getConnection();
System.out.println(“创建连接成功”);
//1.加载驱动
Class.forName(“com.mysql.jdbc.Driver”);
//2.创建连接

    //3.写sql
    String sql="select * from stu";
    //4.得到statement对象，
    PreparedStatement statement =connection.prepareStatement(sql);
    //5.执行sql
    ResultSet resultSet=statement.executeQuery();

    //6.处理结果集
    while (resultSet.next()){
        int id = resultSet.getInt(1);
        String name = resultSet.getString(2);
        int age = resultSet.getInt(3);
        System.out.println(id + name + age);
    }
    //7.关闭资源
    resultSet.close();
    statement.close();
    connection.close();

}

}
3.替换后的运行结果为以下截图，即为成功