[20160731]read a file and print it on the screen

//read a file and print it on the screen
import java.io.*;

public class MyPrintStreamTest2{
public static void main(String[] args) {
String filename = args[0];    // firsttime to see!!!
if(filename!=null){ list(filename,System.out); }
}

public static void list(String filename,PrintStream ps){
try
{
BufferedReader br = new BufferedReader( new FileReader(filename) );
String s = null;
while ((s=br.readLine())!=null) {
ps.println(s);
}
br.close();
}

catch(IOException e)
{
ps.println("reading file error!");
}

}
}