第九章java教程

5、下面哪个选项能够构造一个BufferedInputStream流？() A. New BufferedInputStream(“in.txt”); B. New BufferedInputStream(new File(“in.txt”)); C. New BufferedInputStream(new Write(“in.txt”)); D. New BufferedInputStream(new InputStream(“in.txt”)); E. New BufferedInputStream(new FileInputStream(“in.txt”)); 答案：E 6、下面哪种流可以用于字符输入？() A．java.io.InputStream B. java.io.EncodedReader C. java.io.InputStreamReader D. java.io.InputStreamWrite E. java.io.BufferedInputStream 答案：C 7、下面哪个选项可以构造一个DataOutputStream对象？() A. new DataOutputStream(“out.txt”); B. new DataOutputStream(new File(“out.txt”)); C. new DataOutputStream(new Write(“out.txt”)); D. new DataOutputStream(new OutputStream(“out.txt”)); E. new DataOutputStream(new FileWriter(“out.txt”)); F. new DataOutputStream(new FileOutputStream(“out.txt”)); 答案：F 8、阅读下列程序： //第一行 public class Foo{ public static void main(String args[]){ PrintWriter out=new PrintWriter(new java.io.OutputStreamWriter(System.out),true); out.println(“Hello”); } } 在标记为第一行的地方加入下面哪条语句可以使这个能够编译和执行？() A. import java.io.PrintWriter B. include java.io.PrintWriter C. import java.io.OutputStreamWriter D. include java.io.OutputStreamWriter 答案：A 9、要读一个较大的文件，下列创建对象的方法中哪个是最合适的() A. new FileInputStream(“myfile”); B. new InputStreamReader(new FileInputStream(“myfile”)); C. new BufferedReader(new InputStreamReader(new FileInputStream(“myfile”))); D. new RandomAccessFile raf=new RandomAccessFile(new File(“myfile”,”rw”)); 答案：C 二、编程题 1、编写一个程序，测试异常。该类提供一个输入整数的方法，使用这个方法先输入两个整数，再用第一个整数除以第二个整数，当第二个整数为零时，抛出异常，此时程序要捕获异常。 import java.io.*; public class TestExceptions{ static int getInt() throws IOException{ BufferedReader input=newBufferedReader(new InputStreamReader(System.in)); System.out.print(“Enter an integer:”); String s=input.readLine(); return Integer.parseInt(s); } public static void main(String[] args) { int n1=0,n2=0,n3=0; try { n1=getInt(); n2=getInt(); n3=n1/n2;