单项选择题
A.new BufferedWriter（new FileWriter（“a.txt”））；B.new BufferedReader （new FileInputStream（“a.dat”））；C.new GZIPOutputStream（new FileOutputStream（“a.zip”））；D.new ObjectInputStream（new FileInputStream（“a.dat”））；
A.是B.否
A.floatB.doubleC.FloatD.Double