怎么用java Lambda访问变量

final int num = 1; Converter stringConverter = (from) -> String.valueOf(from + num); stringConverter.convert(2); // 3

class Lambda4 { static int outerStaticNum; int outerNum; void testScopes() { Converter stringConverter1 = (from) -> { outerNum = 23; return String.valueOf(from); }; Converter stringConverter2 = (from) -> { outerStaticNum = 72; return String.valueOf(from); }; } }