本人现在的需求是要使用正则表达式匹配json字符串中符合条件的一对{},{}内的name属性为_id如下图

样例:
{"fields":[{"metadata":{},"name":"id","nullable":true,"type":"integer"},{"metadata":{},"name":"_id","nullable":true,"type":"string"},{"metadata":{},"name":"test","nullable":true,"type":"string"},{"metadata":{},"name":"age","nullable":true,"type":"integer"},{"metadata":{},"name":"name","nullable":true,"type":"string"},{"metadata":{},"name":"testnum","nullable":true,"type":"decimal(19,0)"}],"type":"struct"}
请教下大家,感谢