lambda表达式在序列化时系统会自动生成writeReplace方法，该方法返回SerializedLambda对象，包含了lambda表达式的信息，包括类名方法名。

例如：

public interface FieldChecker<T, R> {default R checkField(SFunction<T, R> sFunction, T t) throws Exception {Class lambdaClass = sFunction.getClass();Method method = lambdaClass.getDeclaredMethod("writeReplace");method.setAccessible(Boolean.TRUE);SerializedLambda serializedLambda = (SerializedLambda) method.invoke(sFunction);//lambda 表达式方法名String methodName = serializedLambda.getImplMethodName();//lambda 表达式类名String classN = serializedLambda.getImplClass();System.out.println(methodName);System.out.println(classN);return sFunction.apply(t);}
}

public class FieldCheckerImpl<T, R> implements FieldChecker<T, R> {public static void main(String[] args) throws Exception {FieldChecker<Person, String> s = new FieldCheckerImpl<>();s.checkField(Person::getName, new Person());}
}class Person {private String name;public String getName() {return name;}public void setName(String name) {this.name = name;}
}

输出：

getName
com/.../Person

mybatis-plus 也是利用SerializedLambda来实现的。