package com.ljs.dao;

import java.sql.Connection;

import java.util.ArrayList;

import java.util.List;

import org.apache.commons.dbutils.QueryRunner;

import org.apache.commons.dbutils.handlers.BeanHandler;

import org.apache.commons.dbutils.handlers.BeanListHandler;

import org.apache.commons.dbutils.handlers.ScalarHandler;

import com.ljs.util.JDBCUtil;

public class DBUtilDao{

    QueryRunner qRunner = new QueryRunner();

    Connection connection = null;

    /*

     *  查询多条结果。

     */

    public<T> List<T> queryMutil(Class<T> clazz, String sql, Object...object){

        List<T> list = new ArrayList<>();

        try {

            connection = JDBCUtil.getConn();

            list = qRunner.query(connection, sql,new BeanListHandler<T>(clazz),object);

        }catch (Exception e) {

            e.printStackTrace();

        }finally {

            JDBCUtil.close(null, null, connection);

        }

        return list;

    }

    /*

     *  查询一条结果。

     */

    public<T> T queryOne(Class<T> clazz, String sql, Object...objects){

        try {

            connection = JDBCUtil.getConn();

            T t = clazz.newInstance();

            t = qRunner.query(connection, sql, new BeanHandler<T>(clazz), objects);

            return t;

        } catch (Exception e) {

            e.printStackTrace();

        }

        return null;

    }

    /*

     * 更新表

     */

    public<T> void update(String sql, Object...objects){

        try {

            connection = JDBCUtil.getConn();

            qRunner.update(connection, sql, objects);

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

    /*

     * 查询某个数scalar

     */

    public String scalar(String sql, Object...objects){

        try {

            connection = JDBCUtil.getConn();

            return qRunner.query(connection, sql,new ScalarHandler<>(), objects).toString();

        } catch (Exception e) {

            e.printStackTrace();

        }

        return null;

    }

}