java编程输入输出有关问题

package util;import java.io.File;import java.io.FileReader;import java.io.FileWriter;import java.io.IOException;public class FileWriterTester {    public static void main(String[] args) throws IOException {        long l = 4657646574646L;        FileWriter writer = new FileWriter("D:/temp");        writer.write(longToChar(l));        writer.flush();        writer.close();        FileReader reader = new FileReader("D:/temp");        char[] c = new char[4];        reader.read(c);        reader.close();        System.err.println(charToLong(c) == l);        new File("D:/temp").delete();    }    public static char[] longToChar(long l) {        char[] chars = new char[4];        for (int i = 0; i < 4; i++) {            chars[i] = (char) (l << (i * 16) >> (16 * 3));        }        return chars;    }    public static long charToLong(char[] c) {        long result = 0;        for (int i = 0; i < 4; i++) {            long temp = c[i];            result |= temp << (16 * (3 - i));        }        return result;    }}