JDBC——JDBCTools

package webPractice;

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

public class JDBCTools {

    public static Connection getConnection() throws Exception{

            Properties properties = new Properties();

            InputStream in = JDBCTools.class.getClassLoader().getResourceAsStream("jdbc.properties");
            properties.load(in);

            String driver = properties.getProperty("driver");
            String url = properties.getProperty("url");
            String user = properties.getProperty("user");
            String password = properties.getProperty("password");

            Class.forName(driver);

            Connection connection = DriverManager.getConnection(url, user, password);

            return connection;
    }


    /*
    包括INSERT DELETE UPDATE 但是不包括SELECT
    所以不需要返回值
     */
    public static void update(String sql, Object ...args){
        Connection connection = null;
        PreparedStatement ps = null;


        try {
            connection = getConnection();
            ps = connection.prepareStatement(sql);
            for(int i = 0; i < args.length; i++){
                ps.setObject(i + 1, args[i]);
            }
            ps.executeUpdate();
        }catch(Exception e){
            e.printStackTrace();
        }finally{
            if(ps!= null){
                try {
                    ps.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if(connection != null){
                try {
                    connection.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }

    }


    /*
    SELECT
     */
    public static String[] resultSet(String sql){

        String[] res = new String[2];
        Connection connection = null;
        PreparedStatement ps = null;
        ResultSet resultSet = null;
       // ResultSetMetaData resultSetMetaData = null;

        try{
            connection = getConnection();
            ps = connection.prepareStatement(sql);
            resultSet = ps.executeQuery();
            //resultSetMetaData = resultSet.getMetaData();

            if(resultSet.next()){
                res[0]= resultSet.getString(1);
                res[1]= resultSet.getString(2);
            }

        }catch(Exception e){
            e.printStackTrace();
        }finally{
            if(resultSet != null){
                try {
                    resultSet.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if(ps!= null){
                try {
                    ps.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if(connection != null){
                try {
                    connection.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }

        }
        return res;

    }

}

　　

url=jdbc:mysql://localhost:3306/db_person
user=root
password=1234
driver=com.mysql.jdbc.Driver