请问这个JOSN三层怎么分别遍历出来
[{"id":"1","pid":"0","name":"一级菜单","_child":[{"id":"2","pid":"1","name":"二级菜单","_child":[{"id":"39","pid":"2","name":"集团CRM"},{"id":"40","pid":"2","name":"三级菜单A"},{"id":"41","pid":"2","name":"三级菜单B"},{"id":"42","pid":"2","name":"三级菜单C"},{"id":"43","pid":"2","name":"三级菜单D"},{"id":"44","pid":"2","name":"三级菜单E"},{"id":"45","pid":"2","name":"三级菜单F"},{"id":"46","pid":"2","name":"三级菜单G"}]}]}]