利用InputStreamReader的read()方法读取时有乱码

读取.docx结尾的文件时有乱码，读取.txt文件时控制台正常输出

public static void main(String[] args) throws IOException{

InputStreamReader in=new InputStreamReader(new FileInputStream("F:\\src.docx"),"gbk");

int c;

while((c=in.read())!=-1){

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

}

/*char[] buf=new char[200];

int c;

while((c=in.read(buf,0,buf.length))!=-1){

String s=new String(buf,0,buf.length);

System.out.print(s);

}*/

in.close();

}