Question

一旦我对makefile进行了一些更改，运行它之后我有以下makefile，现在当我运行它时，我得到一个“make：没有什么可以为`default'做。”我该怎么强迫它重建？我执行“make”并“make clean”，当我输入“make”时，我仍然会收到错误消息。

另外，如何将src目录中的log4.properties文件复制到目标目录（在make文件和命令行中：javac -classpath src：lib / log4j-1.2）。 16.jar src / * .java -d bin）？

#
# define compiler and compiler flag variables
#

JFLAGS = -g -cp .:src:lib/log4j-1.2.16.jar
JC = javac


#
# Clear any default targets for building .class files from .java files; we 
# will provide our own target entry to do this in this makefile.
# make has a set of default targets for different suffixes (like .c.o) 
# Currently, clearing the default for .java.class is not necessary since 
# make does not have a definition for this target, but later versions of 
# make may, so it doesn't hurt to make sure that we clear any default 
# definitions for these
#

.SUFFIXES: .java .class


#
# Here is our target entry for creating .class files from .java files 
# This is a target entry that uses the suffix rule syntax:
#   DSTS:
#       rule
#  'TS' is the suffix of the target file, 'DS' is the suffix of the dependency 
#  file, and 'rule'  is the rule for building a target  
# '$*' is a built-in macro that gets the basename of the current target 
# Remember that there must be a  before the command line ('rule') 
#

.java.class:
    $(JC) $(JFLAGS) $*.java


#
# CLASSES is a macro consisting of 4 words (one for each java source file)
#

CLASSES = \
    src/MatrixDriver.java \
    src/ConcreteMatrix.java \
    src/Matrix.java \
    src/Submatrix.java 


#
# the default make target entry
#

default: classes


#
# This target entry uses Suffix Replacement within a macro: 
# $(name:string1=string2)
#   In the words in the macro named 'name' replace 'string1' with 'string2'
# Below we are replacing the suffix .java of all words in the macro CLASSES 
# with the .class suffix
#

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


#
# RM is a predefined macro in make (RM = rm -f)
#

clean: FORCE
    $(RM) *.class

FORCE:

Answer 1

问题在于：

.java.class:
    $(JC) $(JFLAGS) $*.java

不符合您的想法。也许你的意思是这样的？

%.class: %.java
    $(JC) $(JFLAGS) $^

Answer 2

我没有仔细阅读你的Makefile，我不认为自己是制作专家但

似乎没有任何依赖于Makefile本身
你改变的是Makefile

让我认为正确的行为正是你所描述的。也许您可以在Makefile中添加依赖项。

Answer 3

确保没有名为classes的文件或目录。然后，Make可以假设没什么可做的。

为Java / Linux制作文件

3 个答案: