JDBC工具类

package com.jd.util.db;

import java.sql.*;
import java.util.Properties;

public class DBUtil {

    static {
        //1、加载驱动类
        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

    //2.获取MySQL连接
    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,userName,password);
    }

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

    private static void close(Connection connection,Statement statement,ResultSet resultSet){
        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 select(String sql,IRowMapper rowMapper){

        Connection connection =null;
        Statement statement =null;
        ResultSet resultSet =null;
        try {
            //2、获取MySQL连接
            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
            rowMapper.mapRow(resultSet);
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        } finally {
            //6、释放资源
            close(connection,statement,resultSet);
        }
    }

    public static boolean exist(String sql){
        Connection connection= null;
        Statement statement =null;
        ResultSet resultSet =null;
        try {
            connection = getConnection();
            statement = connection.createStatement();
            resultSet = statement.executeQuery(sql);
            return resultSet.next();

        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        close(connection,statement,resultSet);
        return false;
    }

    public static boolean exist(String sql,Object...params){
        Connection connection= null;
        PreparedStatement preparedStatement=null;
        ResultSet resultSet =null;
        try {
            connection = getConnection();
            //创建sql语句
            preparedStatement = connection.prepareStatement(sql);
            //运行sql语句
            for (int i = 0; i < params.length; i++) {
                preparedStatement.setObject(i+1,params[i]);
            }
            resultSet = preparedStatement.executeQuery();
            return resultSet.next();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        close(connection,preparedStatement,resultSet);
        return false;
    }

    public static boolean update(String sql){
            Connection connection =null;
            Statement statement =null;
            int effect=0;
        try {
            //2.连接MySQl数据库 venus
            connection = getConnection();
            //3.创建SQL语句
            statement = connection.createStatement();
            //4.执行SQL
            effect = statement.executeUpdate(sql);
            //5.处理结果
            return effect>0;
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }finally {//6.释放资源
           close(connection,statement);
        }
        return false;
    }

    public static boolean update(String sql,Object...params){
        Connection connection =null;
        PreparedStatement preparedStatement =null;
        int effect=0;
        try {
            //2.连接MySQl数据库 venus
            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]);
            }
            //4.执行SQL
            effect = preparedStatement.executeUpdate();
            //5.处理结果
            return effect>0;
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }finally {//6.释放资源
            close(connection,preparedStatement);
        }
        return false;
    }

    public static void select(String sql,IRowMapper rowMapper,Object...params){
        Connection connection =null;
        PreparedStatement preparedStatement=null;
        ResultSet resultSet=null;
        try {
            //2、获取连接
            connection= getConnection();
            //3、创建语句
            preparedStatement = connection.prepareStatement(sql);
            for (int i = 0; i < params.length; i++) {
                preparedStatement.setObject(i+1,params[i]);
            }
            //4、执行SQL
            resultSet= preparedStatement.executeQuery();
            //5、处理结果
            rowMapper.mapRow(resultSet);
            //6、释放资源

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

标签：JDBC,throwables,resultSet,connection,preparedStatement,statement,工具,null
来源： https://www.cnblogs.com/lezai0514/p/14818433.html