package cn.ytu.mybatis.jdbc;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.util.Collection;public class JdbcTest {    public static void main(String[] args){        Connection connection = null;        PreparedStatement preparedStatement = null;        ResultSet resultSet = null;                try{            //加载数据库驱动            Class.forName("com.mysql.jdbc.Driver");                        //通过驱动管理类获取数据连接            connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/yanda?characterEncodeing=utf-8","root","123456");            //定义sql语句？表示占位符            String sql = "select * from user where username = ?";            //获取预处理的statement            preparedStatement = connection.prepareStatement(sql);            //设置参数，第一个参数为sql语句中参数的序号（从1开始），第二个参数为设置的参数值            preparedStatement.setString(1,"王五");            //向数据库发出sql执行查询，查询出结果集            resultSet = preparedStatement.executeQuery();            //遍历查询结果集            while(resultSet.next()){                System.out.println(resultSet.getString("id")+" "+resultSet.getString("username"));            }        }catch(Exception e){            e.printStackTrace();        }finally{            //释放资源            if(resultSet != null){                try{                    resultSet.close();                }catch(SQLException e){                    e.printStackTrace();                }            }        }                if(preparedStatement != null){            try{                connection.close();            }catch(SQLException e){                e.printStackTrace();            }        }                    if(connection != null){            try{                connection.close();            }catch(SQLException e){                e.printStackTrace();            }        }    }}

项目结构：

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