Parse Wordpress JSON with PHP

对于PHP初学者来说，Wordpress存储在mySql数据库中的JSON结构相当复杂。但我想从复杂的JSON结构中获得某些信息。你能用PHP帮助把这个JSON字符串中的数据以一种人性化的结构提取出来吗？

我想获取"文件"元素附近的文件名：

a: 5: {
s: 5: "width";i: 428;s: 6: "height";i: 324;s: 4: "file";s: 15: "Clipboard12.jpg";s: 5: "sizes";a: 9: {
    s: 9: "thumbnail";a: 4: {
        s: 4: "file";s: 23: "Clipboard12-150x150.jpg";s: 5: "width";i: 150;s: 6: "height";i: 150;s: 9: "mime-type";s: 10: "image/jpeg";
    }
    s: 6: "medium";a: 4: {
        s: 4: "file";s: 23: "Clipboard12-300x227.jpg";s: 5: "width";i: 300;s: 6: "height";i: 227;s: 9: "mime-type";s: 10: "image/jpeg";
    }
    s: 14: "post-thumbnail";a: 4: {
        s: 4: "file";s: 22: "Clipboard12-100x65.jpg";s: 5: "width";i: 100;s: 6: "height";i: 65;s: 9: "mime-type";s: 10: "image/jpeg";
    }
    s: 9: "art-thumb";a: 4: {
        s: 4: "file";s: 22: "Clipboard12-100x65.jpg";s: 5: "width";i: 100;s: 6: "height";i: 65;s: 9: "mime-type";s: 10: "image/jpeg";
    }
    s: 8: "art-wide";a: 4: {
        s: 4: "file";s: 23: "Clipboard12-326x159.jpg";s: 5: "width";i: 326;s: 6: "height";i: 159;s: 9: "mime-type";s: 10: "image/jpeg";
    }
    s: 12: "art-big-1col";a: 4: {
        s: 4: "file";s: 23: "Clipboard12-326x235.jpg";s: 5: "width";i: 326;s: 6: "height";i: 235;s: 9: "mime-type";s: 10: "image/jpeg";
    }
    s: 15: "art-slide-small";a: 4: {
        s: 4: "file";s: 23: "Clipboard12-326x324.jpg";s: 5: "width";i: 326;s: 6: "height";i: 324;s: 9: "mime-type";s: 10: "image/jpeg";
    }
    s: 7: "art-gal";a: 4: {
        s: 4: "file";s: 23: "Clipboard12-210x210.jpg";s: 5: "width";i: 210;s: 6: "height";i: 210;s: 9: "mime-type";s: 10: "image/jpeg";
    }
    s: 10: "td_198x143";a: 4: {
        s: 4: "file";s: 23: "Clipboard12-198x143.jpg";s: 5: "width";i: 198;s: 6: "height";i: 143;s: 9: "mime-type";s: 10: "image/jpeg";
    }
}
s: 10: "image_meta";a: 11: {
    s: 8: "aperture";i: 0;s: 6: "credit";s: 0: "";s: 6: "camera";s: 0: "";s: 7: "caption";s: 0: "";s: 17: "created_timestamp";i: 0;s: 9: "copyright";s: 0: "";s: 12: "focal_length";i: 0;s: 3: "iso";i: 0;s: 13: "shutter_speed";i: 0;s: 5: "title";s: 0: "";s: 11: "orientation";i: 0;
}

}

通过执行PHP文件，我希望看到结果：

Clipboard0340-100x65.jpg
Clipboard0340-150x150.jpg
Clipboard0340-198x143.jpg
Clipboard0340-210x210.jpg
Clipboard0340-300x209.jpg
Clipboard0340-326x159.jpg
Clipboard0340-326x235.jpg
Clipboard0340-326x406.jpg
Clipboard0340-513x357.jpg
Clipboard0340-674x357.jpg
Clipboard0340.jpg