JDBC工具类

package db;

import db.IRowMapper;

import java.sql.*;


public class DBUtill {
    public static void main(String[] args) {


    }


    public static void load() {
        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

    /**
     * 获取sql连接
     *
     * @author csq
     */
    private static Connection getConnection() throws SQLException {
        String url = PropertiesUtil.value("url");
        String userName = PropertiesUtil.value("userName");
        String password = PropertiesUtil.value("password");
        return DriverManager.getConnection(url, "root", "123");

    }

    public static void select(String sql, IRowMapper iRowMapper) {
        //1.加载驱动类
        load();
        //2.连接数据库venus
        Connection connection = null;
        Statement statement = null;
        ResultSet resultSet = null;
        try {
            connection = getConnection();
            //3.创建语句
            statement = connection.createStatement();
            //4.执行sql语句
            resultSet = statement.executeQuery(sql);
            //5.处理结果
            iRowMapper.rowMapper(resultSet);
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        } finally {
            //6.释放资源
            close(resultSet, statement, connection);
        }
    }


    public static boolean update(String sql) {
        load();
        //2.连接Mysql数据venus
        Statement statement = null;
        Connection connection = null;
        try {
            connection = getConnection();
            //3.创建SQL语句
            statement = connection.createStatement();
            int effect = statement.executeUpdate(sql);
          return  effect > 0;
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        } finally {
            close(statement, connection);
        }
        return false;
    }

    public static boolean update(String sql, Object... params) {
        load();
        //2.连接Mysql数据venus
        PreparedStatement preparedStatement = null;
        Connection connection = null;
        try {
            connection = getConnection();
            //3.创建SQL语句
            preparedStatement = connection.prepareStatement(sql);
            for (int i = 0; i < params.length; i++) {
                preparedStatement.setObject(i + 1, params[i]);
            }

            int effect = preparedStatement.executeUpdate();

           return effect >0;
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        } finally {
            close(preparedStatement, connection);
        }
        return false;
    }

    public static boolean exists(String sql) {
        load();
        ResultSet resultSet = null;
        Statement statement = null;
        Connection connection = null;
        try {
            connection = getConnection();
            statement = connection.createStatement();

            //4.执行sql语句
            resultSet = statement.executeQuery(sql);
            //5.处理结果
            return resultSet.next();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        } finally {
            //6.释放资源
            close(resultSet, statement, connection);
        }
        return false;
    }


    public static boolean exists(String sql, Object... parms) {
        load();
        ResultSet resultSet = null;
        PreparedStatement preparedStatement = null;
        Connection connection = null;
        try {
            connection = getConnection();
            preparedStatement = connection.prepareStatement(sql);

            for (int i = 0; i < parms.length; i++) {
                preparedStatement.setObject(i + 1, parms[i]);
            }

            //4.执行sql语句
            resultSet = preparedStatement.executeQuery();

            //5.处理结果
            return resultSet.next();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        } finally {
            //6.释放资源
            close(resultSet, preparedStatement, connection);
        }
        return false;
    }

    public static void login(String sql, IRowMapper irowMapper, Object... parmms) {
        //1.加载驱动类
        load();
        Connection connection = null;
        PreparedStatement preparedStatement = null;
        ResultSet resultSet = null;


        try {
            connection = getConnection();
            //3.创建语句
            //4.执行sql
            preparedStatement = connection.prepareStatement(sql);
            for (int i = 0; i < parmms.length; i++) {
                preparedStatement.setObject(i + 1, parmms[i]);
            }

            resultSet = preparedStatement.executeQuery();
            irowMapper.rowMapper(resultSet);
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        } finally {
            close(resultSet, preparedStatement, connection);
        }

    }

    public static void close(ResultSet resultSet, Statement statement, Connection connection) {
        if (resultSet != null) {
            try {
                resultSet.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        if (statement != null) {
            try {
                statement.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        if (connection != null) {
            try {
                connection.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
    }


    public static void close(Statement statement, Connection connection) {
        if (statement != null) {
            try {
                statement.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        if (connection != null) {
            try {
                connection.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
    }
}

IRowMapper接口

interface IRowMapper {
    void rowMapper(ResultSet resultSet);
}