PHP5.2.0及以上版本具有json_decode函数,该函数是用来解析JSON格式的数据,可以返回array（数组）或object（对象）两种结果，,下面将分两种情况具体介绍json_decode的用法以及如何取得我们想要的值.

1.json_decode()

(PHP 5 >= 5.2.0, PECL json >= 1.2.0)

json_decode — 对 JSON 格式的字符串进行编码

说明:mixed json_decode ( string $json [, bool $assoc ] )

接受一个 JSON 格式的字符串并且把它转换为 PHP 变量

参数:json

待解码的 json string 格式的字符串.

assoc:当该参数为 TRUE 时,将返回 array 而非 object.

返回值:Returns an object or if the optional assoc parameter is TRUE, an associative array is instead returned.

范例代码如下:

1. <?php
2. $json = '{"a":1,"b":2,"c":3,"d":4,"e":5}';
3. var_dump(json_decode($json));
4. var_dump(json_decode($json, true));
5. ?>
6. //上例将输出：
7. object(stdClass)#1 (5) {
8. ["a"] => int(1)
9. ["b"] => int(2)
10. ["c"] => int(3)
11. ["d"] => int(4)
12. ["e"] => int(5)
13. }
14. array(5) {
15. ["a"] => int(1)
16. ["b"] => int(2)
17. ["c"] => int(3)
18. ["d"] => int(4)
19. ["e"] => int(5)
20. }
21. $data='[{"Name":"a1","Number":"123","Contno":"000","QQNo":""},{"Name":"a1","Number":"123","Contno":"000","QQNo":""},{"Name":"a1","Number":"123","Contno":"000","QQNo":""}]';
22. echo json_decode($data);
23. //结果为：
24. Array ( [0] => stdClass Object ( [Name] => a1 [Number] => 123 [Contno] => 000 [QQNo] => ) [1] => stdClass Object ( [Name] => a1 [Number] => 123 [Contno] => 000 [QQNo] => ) [2] => stdClass Object ( [Name] => a1 [Number] => 123 [Contno] => 000 [QQNo] => ) )

可以看出经过json_decode()编译出来的是对象,现在输出json_decode($data,true)试下,代码如下:

1. echo json_decode($data,true);
2. //结果：
3. Array ( [0] => Array ( [Name] => a1 [Number] => 123 [Contno] => 000 [QQNo] => ) [1] => Array ( [Name] => a1 [Number] => 123 [Contno] => 000 [QQNo] => ) [2] => Array ( [Name] => a1 [Number] => 123 [Contno] => 000 [QQNo] => ) )

可以看出 json_decode($data,true)输出的一个关联数组,由此可知json_decode($data）输出的是对象,而json_decode("$arr",true)是把它强制生成PHP关联数组.

假如我们获取的JSON数据如下:(可以使用curl、fsockopen等方式获取),代码如下:

1. {
2. "from":"zh",
3. "to":"en",
4. "trans_result":[
5. {
6. "src":"u4f60u597d",
7. "dst":"Hello"
8. }
9. ]
10. }

一、json_decode返回array的方式:

json_decode($data,true);用json_decode函数返回array的方式得到:

1. Array
2. (
3. [from] => zh
4. [to] => en
5. [trans_result] => Array
6. (
7. [0] => Array
8. (
9. [src] => 你好
10. [dst] => Hello
11. )
12. )
13. )

我们在PHP语言中可以用以下方法取得我们想要的值,代码如下:

1. <?php
2. $data = <<<STR
3. {
4. "from":"zh",
5. "to":"en",
6. "trans_result":[
7. {
8. "src":"u4f60u597d",
9. "dst":"Hello"
10. }
11. ]
12. }
13. STR;
14. $jsondata=json_decode($data,true);
15. header("Content-Type: text/html; charset=UTF-8");
16. print_r($jsondata);
17. echo "<br />".$jsondata['to']; //en
18. echo "<br />".$jsondata['trans_result'][0]['dst']; //Hello
19. ?>

二、json_decode返回object的方式:

json_decode($data);

用json_decode函数返回object的方式得到:

1. stdClass Object
2. (
3. [from] => zh
4. [to] => en
5. [trans_result] => Array
6. (
7. [0] => stdClass Object
8. (
9. [src] => 你好
10. [dst] => Hello
11. )
12. )
13. )

我们在PHP语言中可以用以下方法取得我们想要的值,代码如下:

1. <?php
2. $data = <<<STR
3. {
4. "from":"zh",
5. "to":"en",
6. "trans_result":[
7. {
8. "src":"u4f60u597d",
9. "dst":"Hello"
10. }
11. ]
12. }
13. STR;
14. $jsondata=json_decode($data);
15. header("Content-Type: text/html; charset=UTF-8");
16. print_r($jsondata);
17. echo "<br />".$jsondata->from; //zh
18. echo "<br />".$jsondata->trans_result[0]->src; //你好
19. ?>