安装redis出错

在程序里面使用reids::get(),打开网页就报下面这个错Class 'Predis\Client' not found 。
在composer运行命令composer require predis/predis 就报下面这个错
[Seld\JsonLint\ParsingException]
"./composer.json" does not contain valid JSON
Parse error on line 13:
...~7.0", }, "require-dev"
--------------------^
Expected: 'STRING' - It appears you have an extra trailing comma