php单态设计模式，我的理解，类中创建静态变量，使其只有一个，使用方法进行返回对象，该方法 检查对象是存在不存在就创建。从而实现单一对象。
将__construct()设置为private这样就new不了咯.self是本类的意思。“::”调用静态方法
[php] show();
/*//直接new 会报错的噢!!!
new myclass();
new myclass();
new myclass();
new myclass();
new myclass();
new myclass();
new myclass();
new myclass();*/
?>
show();
/*//直接new 会报错的噢!!!
new myclass();
new myclass();
new myclass();
new myclass();
new myclass();
new myclass();
new myclass();
new myclass();*/
?>
这个是小例子.下面给出 单态的 mysql类
[php] db_mysql_hostname = $hostname_or_conf['hostname'];
$this->db_mysql_username = $hostname_or_conf['username'];
$this->db_mysql_password = $hostname_or_conf['password'];
$this->db_mysql_database = $hostname_or_conf['database'];
$this->db_mysql_port = isset($hostname_or_conf['port'])?$hostname_or_conf['port']:'3306';
$this->db_mysql_charset = isset($hostname_or_conf['charset'])?$hostname_or_conf['charset']:'utf8';
}elseif(!empty($hostname_or_conf)||!empty($username)||!empty($password)||!empty($database))
{
$this->db_mysql_hostname = $hostname_or_conf;
$this->db_mysql_username = $username;
$this->db_mysql_password = $password;
$this->db_mysql_database = $database;
$this->db_mysql_port = $port;
$this->db_mysql_charset = $char;
}else{
die('configuration error.');
}
$server = $this->db_mysql_hostname.':'.$this->db_mysql_port;
$this->conn = mysql_connect($server,$this->db_mysql_username,$this->db_mysql_password,true) or die('connect mysql db error!');
mysql_select_db($this->db_mysql_database,$this->conn) or die('select db error!');
mysql_query(set names . $this->db_mysql_charset, $this->conn);
}
/**
+----------------------------------------------------------
* 设置数据对象值
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
*table,where,order,limit,data,field,join,group,having
+----------------------------------------------------------
*/
public function table($table){
$this->query_list['table'] = $table;
return $this;
}
public function where($where){
$this->query_list['where'] = $where;
return $this;
}
public function order($order){
$this->query_list['order'] = $order;
return $this;
}
public function limit($offset,$length=null){
if (is_null($length)) {
$this->query_list['limit']='limit '.$offset;
return $this;
}else {
if(!isset($length)){
$length = $offset;
$offset = 0;
}
$this->query_list['limit'] = 'limit '.$offset.','.$length;
return $this;
}
}
public function data($data){
//读取数据表字段,然后处理表单数据
$datalist = $this->getfields($this->query_list['table']);
$arr=array();
foreach ($datalist as $key=>$value) {
if (array_key_exists ($key,$data) ) {
$arr[$key]=$data[$key];
}
}
//var_dump($arr);
/*
if(is_object($data)){
$data = get_object_vars($data);
}elseif (is_string($data)){
parse_str($data,$data);
}elseif(!is_array($data)){
//log:data_type_invalid
}
*/
$this->query_list['data'] = $arr;
return $this;
}
public function field($fields){
$this->query_list['fields'] = $fields;
return $this;
}
public function join($join){
$this->query_list['join'] = $join;
return $this;
}
public function group($group){
$this->query_list['group'] = $group;
return $this;
}
public function having($having){
$this->query_list['having'] = $having;
return $this;
}
/**
+----------------------------------------------------------
* 查询
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
* @param
+----------------------------------------------------------
*/
public function select(){
$select_sql = 'select ';
$fields = isset($this->query_list['fields'])?$this->query_list['fields']:'*';
$select_sql.=$fields;
$select_sql.= ' from `'.$this->query_list['table'].'` ';
isset($this->query_list['join'])?($select_sql.=$this->query_list['join']):'';
isset($this->query_list['where'])?($select_sql.=' where '.$this->query_list['where']):'';
isset($this->query_list['group'])?($select_sql.=' group by'.$this->query_list['group']):'';
isset($this->query_list['having'])?($select_sql.=' mysql having '.$this->query_list['having']):'';
isset($this->query_list['order'])?($select_sql.=' order by '.$this->query_list['order']):'';
isset($this->query_list['limit'])?($select_sql.=' '.$this->query_list['limit']):'';
// echo '----->'.$select_sql;
return $this->query($select_sql);
}
/**
+----------------------------------------------------------
* 增加
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
* @param
+----------------------------------------------------------
*/
public function add(){
$add_sql = 'insert into `'.$this->query_list['table'].'` (';
$data = $this->query_list['data'];
$value = $field = '';
foreach($data as $k=>$v){
$field .= '`'.$k.'`,';
if(is_numeric($v))
$value .= $v.',';
else
$value .= '\''.$v.'\',';
}
$add_sql .= rtrim($field,',').') values ('.rtrim($value,',').')';
// echo 'add_sql'.$add_sql;
return $this->execute($add_sql);
}
/**
+----------------------------------------------------------
* 删除
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
* @param
+----------------------------------------------------------
*/
public function delete(){
$del_sql = 'delete from `'.$this->query_list['table'].'` where '.$this->query_list['where'];
if(isset($this->query_list['order']))
$del_sql .= 'order by '.$this->query_list['order'];
if(isset($this->query_list['limit']))
$del_sql .= ' '.$this->query_list['limit'];
return $this->execute($del_sql);
}
/**
+----------------------------------------------------------
* 更新
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
* @param
+----------------------------------------------------------
*/
public function update(){
$update_sql = 'update `'.$this->query_list['table'].'` set ';
$data = $this->query_list['data'];
foreach($data as $k=>$v){
if(is_numeric($v))
$update_sql .= '`'.$k.'` ='.$v.',';
else
$update_sql .= '`'.$k.'` =\''.$v.'\',';
}
$update_sql = rtrim($update_sql,',');
if(isset($this->query_list['where']))
$update_sql .= ' where '.$this->query_list['where'];
if(isset($this->query_list['order']))
$update_sql .= ' order by '.$this->query_list['order'];
if(isset($this->query_list['limit']))
$update_sql .= ' '.$this->query_list['limit'];
return $this->execute($update_sql);
}
/**
+----------------------------------------------------------
* 执行查询 返回数据集
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
* @param string $sql sql指令
*/
public function query($sql) {
if ( !$this->conn ) return false;
$this->querystr = $sql;
//释放前次的查询结果
if ( $this->queryid ) { $this->free(); }
$this->query_start_time = microtime(true);
$this->queryid = mysql_query($sql, $this->conn);
$this->query_count++;
if ( false === $this->queryid ) {
$this->error();
return false;
} else {
$this->numrows = mysql_num_rows($this->queryid);
return $this->getall();
}
}
/**
+----------------------------------------------------------
* 执行语句
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
* @param string $sql sql指令
+----------------------------------------------------------
*/
public function execute($sql) {
if ( !$this->conn ) return false;
$this->querystr = $sql;
//释放前次的查询结果
if ( $this->queryid ) { $this->free(); }
$this->query_start_time = microtime(true);
$result = mysql_query($sql, $this->conn) ;
$this->query_count++;
if ( false === $result) {
$this->error();
return false;
} else {
$this->numrows = mysql_affected_rows($this->conn);
return $this->numrows;
}
}
/**
+----------------------------------------------------------
* 获得所有的查询数据
+----------------------------------------------------------
* @access private
+----------------------------------------------------------
* @return array
*/
private function getall() {
//返回数据集
$result = array();
if($this->numrows >0) {
while($row = mysql_fetch_assoc($this->queryid)){
$result[] = $row;
}
mysql_data_seek($this->queryid,0);
}
return $result;
}
/**
+----------------------------------------------------------
* 取得数据表的字段信息
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
*/
public function getfields($tablename) {
$result = $this->query('show columns from `'.$tablename.'`');
$info = array();
if($result) {
foreach ($result as $key => $val) {
$info[$val['field']] = array(
'name' => $val['field'],
'type' => $val['type'],
'notnull' => (bool) ($val['null'] === ''), // not null is empty, null is yes
'default' => $val['default'],
'primary' => (strtolower($val['key']) == 'pri'),
'autoinc' => (strtolower($val['extra']) == 'auto_increment'),
);
}
}
return $info;
}
/**
+----------------------------------------------------------
* 取得数据库的表信息
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
*/
public function gettables($dbname='') {
if(!empty($dbname)) {
$sql = 'show tables from '.$dbname;
}else{
$sql = 'show tables ';
}
$result = $this->query($sql);
$info = array();
foreach ($result as $key => $val) {
$info[$key] = current($val);
}
return $info;
}
/**
+----------------------------------------------------------
* 最后次操作的id
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
* @param
+----------------------------------------------------------
*/
public function last_insert_id(){
return mysql_insert_id($this->conn);
}
/**
* 执行一条带有结果集计数的
*/
public function count($sql){
return $this->execute($sql);
}
/**
+----------------------------------------------------------
* 启动事务
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
* @return void
+----------------------------------------------------------
*/
public function starttrans() {
if ($this->transtimes == 0) {
mysql_query('start transaction', $this->conn);
}
$this->transtimes++;
return ;
}
/**
+----------------------------------------------------------
* 提交事务
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
* @return boolen
+----------------------------------------------------------
*/
public function commit()
{
if ($this->transtimes > 0) {
$result = mysql_query('commit', $this->conn);
$this->transtimes = 0;
if(!$result){
throw new exception($this->error());
}
}
return true;
}
/**
+----------------------------------------------------------
* 事务回滚
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
* @return boolen
+----------------------------------------------------------
*/
public function rollback()
{
if ($this->transtimes > 0) {
$result = mysql_query('rollback', $this->conn);
$this->transtimes = 0;
if(!$result){
throw new exception($this->error());
}
}
return true;
}
/**
+----------------------------------------------------------
* 错误信息
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
* @param
+----------------------------------------------------------
*/
public function error() {
$this->error = mysql_error($this->conn);
if('' != $this->querystr){
$this->error .= \n [ sql语句 ] : .$this->querystr;
}
return $this->error;
}
/**
+----------------------------------------------------------
* 释放查询结果
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
*/
public function free() {
@mysql_free_result($this->queryid);
$this->queryid = 0;
$this->query_list = null;
}
/**
+----------------------------------------------------------
* 关闭连接
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
* @param
+----------------------------------------------------------
*/
function close(){
if ($this->conn && !mysql_close($this->conn)){
throw new exception($this->error());
}
$this->conn = 0;
$this->query_count = 0;
}
/**
+----------------------------------------------------------
* 析构方法
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
*/
function __destruct(){
$this->close();
}
}
db_mysql_hostname = $hostname_or_conf['hostname'];
$this->db_mysql_username = $hostname_or_conf['username'];
$this->db_mysql_password = $hostname_or_conf['password'];
$this->db_mysql_database = $hostname_or_conf['database'];
$this->db_mysql_port = isset($hostname_or_conf['port'])?$hostname_or_conf['port']:'3306';
$this->db_mysql_charset = isset($hostname_or_conf['charset'])?$hostname_or_conf['charset']:'utf8';
}elseif(!empty($hostname_or_conf)||!empty($username)||!empty($password)||!empty($database))
{
$this->db_mysql_hostname = $hostname_or_conf;
$this->db_mysql_username = $username;
$this->db_mysql_password = $password;
$this->db_mysql_database = $database;
$this->db_mysql_port = $port;
$this->db_mysql_charset = $char;
}else{
die('configuration error.');
}
$server = $this->db_mysql_hostname.':'.$this->db_mysql_port;
$this->conn = mysql_connect($server,$this->db_mysql_username,$this->db_mysql_password,true) or die('connect mysql db error!');
mysql_select_db($this->db_mysql_database,$this->conn) or die('select db error!');
mysql_query(set names . $this->db_mysql_charset, $this->conn);
}
/**
+----------------------------------------------------------
* 设置数据对象值
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
*table,where,order,limit,data,field,join,group,having
+----------------------------------------------------------
*/
public function table($table){
$this->query_list['table'] = $table;
return $this;
}
public function where($where){
$this->query_list['where'] = $where;
return $this;
}
public function order($order){
$this->query_list['order'] = $order;
return $this;
}
public function limit($offset,$length=null){
if (is_null($length)) {
$this->query_list['limit']='limit '.$offset;
return $this;
}else {
if(!isset($length)){
$length = $offset;
$offset = 0;
}
$this->query_list['limit'] = 'limit '.$offset.','.$length;
return $this;
}
}
public function data($data){
//读取数据表字段,然后处理表单数据
$datalist = $this->getfields($this->query_list['table']);
$arr=array();
foreach ($datalist as $key=>$value) {
if (array_key_exists ($key,$data) ) {
$arr[$key]=$data[$key];
}
}
//var_dump($arr);
/*
if(is_object($data)){
$data = get_object_vars($data);
}elseif (is_string($data)){
parse_str($data,$data);
}elseif(!is_array($data)){
//log:data_type_invalid
}
*/
$this->query_list['data'] = $arr;
return $this;
}
public function field($fields){
$this->query_list['fields'] = $fields;
return $this;
}
public function join($join){
$this->query_list['join'] = $join;
return $this;
}
public function group($group){
$this->query_list['group'] = $group;
return $this;
}
public function having($having){
$this->query_list['having'] = $having;
return $this;
}
/**
+----------------------------------------------------------
* 查询
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
* @param
+----------------------------------------------------------
*/
public function select(){
$select_sql = 'select ';
$fields = isset($this->query_list['fields'])?$this->query_list['fields']:'*';
$select_sql.=$fields;
$select_sql.= ' from `'.$this->query_list['table'].'` ';
isset($this->query_list['join'])?($select_sql.=$this->query_list['join']):'';
isset($this->query_list['where'])?($select_sql.=' where '.$this->query_list['where']):'';
isset($this->query_list['group'])?($select_sql.=' group by'.$this->query_list['group']):'';
isset($this->query_list['having'])?($select_sql.=' mysql having '.$this->query_list['having']):'';
isset($this->query_list['order'])?($select_sql.=' order by '.$this->query_list['order']):'';
isset($this->query_list['limit'])?($select_sql.=' '.$this->query_list['limit']):'';
// echo '----->'.$select_sql;
return $this->query($select_sql);
}
/**
+----------------------------------------------------------
* 增加
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
* @param
+----------------------------------------------------------
*/
public function add(){
$add_sql = 'insert into `'.$this->query_list['table'].'` (';
$data = $this->query_list['data'];
$value = $field = '';
foreach($data as $k=>$v){
$field .= '`'.$k.'`,';
if(is_numeric($v))
$value .= $v.',';
else
$value .= '\''.$v.'\',';
}
$add_sql .= rtrim($field,',').') values ('.rtrim($value,',').')';
// echo 'add_sql'.$add_sql;
return $this->execute($add_sql);
}
/**
+----------------------------------------------------------
* 删除
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
* @param
+----------------------------------------------------------
*/
public function delete(){
$del_sql = 'delete from `'.$this->query_list['table'].'` where '.$this->query_list['where'];
if(isset($this->query_list['order']))
$del_sql .= 'order by '.$this->query_list['order'];
if(isset($this->query_list['limit']))
$del_sql .= ' '.$this->query_list['limit'];
return $this->execute($del_sql);
}
/**
+----------------------------------------------------------
* 更新
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
* @param
+----------------------------------------------------------
*/
public function update(){
$update_sql = 'update `'.$this->query_list['table'].'` set ';
$data = $this->query_list['data'];
foreach($data as $k=>$v){
if(is_numeric($v))
$update_sql .= '`'.$k.'` ='.$v.',';
else
$update_sql .= '`'.$k.'` =\''.$v.'\',';
}
$update_sql = rtrim($update_sql,',');
if(isset($this->query_list['where']))
$update_sql .= ' where '.$this->query_list['where'];
if(isset($this->query_list['order']))
$update_sql .= ' order by '.$this->query_list['order'];
if(isset($this->query_list['limit']))
$update_sql .= ' '.$this->query_list['limit'];
return $this->execute($update_sql);
}
/**
+----------------------------------------------------------
* 执行查询 返回数据集
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
* @param string $sql sql指令
*/
public function query($sql) {
if ( !$this->conn ) return false;
$this->querystr = $sql;
//释放前次的查询结果
if ( $this->queryid ) { $this->free(); }
$this->query_start_time = microtime(true);
$this->queryid = mysql_query($sql, $this->conn);
$this->query_count++;
if ( false === $this->queryid ) {
$this->error();
return false;
} else {
$this->numrows = mysql_num_rows($this->queryid);
return $this->getall();
}
}
/**
+----------------------------------------------------------
* 执行语句
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
* @param string $sql sql指令
+----------------------------------------------------------
*/
public function execute($sql) {
if ( !$this->conn ) return false;
$this->querystr = $sql;
//释放前次的查询结果
if ( $this->queryid ) { $this->free(); }
$this->query_start_time = microtime(true);
$result = mysql_query($sql, $this->conn) ;
$this->query_count++;
if ( false === $result) {
$this->error();
return false;
} else {
$this->numrows = mysql_affected_rows($this->conn);
return $this->numrows;
}
}
/**
+----------------------------------------------------------
* 获得所有的查询数据
+----------------------------------------------------------
* @access private
+----------------------------------------------------------
* @return array
*/
private function getall() {
//返回数据集
$result = array();
if($this->numrows >0) {
while($row = mysql_fetch_assoc($this->queryid)){
$result[] = $row;
}
mysql_data_seek($this->queryid,0);
}
return $result;
}
/**
+----------------------------------------------------------
* 取得数据表的字段信息
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
*/
public function getfields($tablename) {
$result = $this->query('show columns from `'