2014/9/22

1
System.in

public class wori                                    //先用InputStreamReader套System.in，再用BufferedReader套是常用方法
{
    public static void main(String args[])
    {
        InputStreamReader a = new InputStreamReader(System.in);                // System.in是InputStream父类的引用
        BufferedReader b = new BufferedReader(a);                              
        String s = null;
        try
        {
            while((s = b.readLine()) != null)                //使用BufferedReader的方法readLine()
            {
                if(s.equalsIgnoreCase("exit"))                //
                {
                    break;
                }
                System.out.println(s.toUpperCase());
            }
            b.close();                                                    //b close即可
        }
        catch(IOException e)
        {
            e.printStackTrace();
        }
    }
}

 

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();
    }
}