不要将生成的 Q 类型用于动态表达式创建.您可以使用动态路径代替 http://www.querydsl.com/static/querydsl/2.9.0/reference/html/ch03.html#d0e1379

Don't use the generated Q-types for dynamic Expression creation. You can use dynamic paths instead http://www.querydsl.com/static/querydsl/2.9.0/reference/html/ch03.html#d0e1379

在你的情况下是这样的

Class<?> entityType = Class.forName(...)
PathBuilder entityPath = new PathBuilder(entityType, "entity");
PathBuilder relation = entityPath.get("relation");
Predicate predicate = relation.get...(...).eq(...)

对于路径提取使用这个类 http://www.querydsl.com/static/querydsl/2.9.0/apidocs/com/mysema/query/types/PathExtractor.html

For Path extraction use this class http://www.querydsl.com/static/querydsl/2.9.0/apidocs/com/mysema/query/types/PathExtractor.html

PathExtactor 从给定的 Expression