jar如何修改这个makefile使其能够编译。位于src目录中的java文件？

Question

也就是说，它把。类目录中的类文件？到目前为止，我只能在所有内容都在同一个目录下时才能使其工作

JFLAGS = -g
JC = javac
.SUFFIXES: .java .class
.java.class:
        $(JC) $(JFLAGS) $*.java

# This uses the line continuation character (\) for readability
CLASSES = \
        Context.java \
        ClosedState.java \
        OpenState.java \
        Floor.java \
        State.java \
        Elevator.java

default: classes

classes: $(CLASSES:.java=.class)

clean:
        $(RM) *.class