装饰模式在Java I/O库中的应用

编写一个装饰者把所有的输入流内的大写字符转化成小写字符：

importjava.io.FilterInputStream;

importjava.io.IOException;

importjava.io.InputStream;

publicclassLowerCaseInputStreamextendsFilterInputStream

{

protectedLowerCaseInputStream(InputStreamin)

{

super(in);

}

@Override

publicintread()throwsIOException

{

intc=super.read();

return(c==-1?c:Character.toLowerCase((char)c));

}

@Override

publicintread(byte[]b,intoffset,intlen)throwsIOException

{

intresult=super.read(b,offset,len);

for(inti=offset;i<offset+result;i++)

{

b[i]=(byte)Character.toLowerCase((char)b[i]);

}

returnresult;

}

}

测试我们的装饰者类：

importjava.io.*;

publicclassInputTest

{

publicstaticvoidmain(String[]args)throwsIOException

{

intc;

try

{

InputStreamin=newLowerCaseInputStream(newBufferedInputStream(

newFileInputStream("D:\\test.txt")));

while((c=in.read())>=0)

{

System.out.print((char)c);

}

in.close();

}

catch(IOExceptione)

{

e.printStackTrace();

}

}

}