2014/9/22

1
System.in

 1 public class wori                                    //先用InputStreamReader套System.in，再用BufferedReader套是常用方法
 2 {
 3     public static void main(String args[])
 4     {
 5         InputStreamReader a = new InputStreamReader(System.in);                // System.in是InputStream父类的引用
 6         BufferedReader b = new BufferedReader(a);
 7         String s = null;
 8         try
 9         {
10             while((s = b.readLine()) != null)                //使用BufferedReader的方法readLine()
11             {
12                 if(s.equalsIgnoreCase("exit"))                //
13                 {
14                     break;
15                 }
16                 System.out.println(s.toUpperCase());
17             }
18             b.close();                                                    //b close即可
19         }
20         catch(IOException e)
21         {
22             e.printStackTrace();
23         }
24     }
25 }

2
DataInputStream, DateOutputStream, ByteArrayInputStream, ByteArrayOutputStream 用于直接读写基本类型数据

public class wori
{
    public static void main(String args[])
    {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();       //分配内存给一个字节数组，以此为节点
        DataOutputStream dos = new DataOutputStream(baos);              //
        try
        {
            dos.writeDouble(Math.random());                            //
            ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());  //toByteArray()返回一个字节数组作为节点
            DataInputStream dis = new DataInputStream(bais);
            System.out.println(dis.readDouble());                   //
            dos.close();
            dis.close();
        }
        catch(IOException e)
        {
            System.exit(-1);
        }

    }
}

3
PrintStream

public class wori
{
    public static void main(String args[])
    {
        PrintStream ps = null;
        try
        {
            FileOutputStream fos = new FileOutputStream("d:/1.txt");
            ps = new PrintStream(fos);
        }
        catch(IOException e)
        {
            System.exit(0);
        }
        System.setOut(ps);                               //
        int i = 0;
        while(i < 100)
        {
            System.out.println(i);
            i++;
        }
        ps.close();
    }
}