java 字符串写入文件后再读出不一致？

public class TestString {
public static void main(String[] args) throws Exception {

    String str = "1";
    String password = "x";

    char s[] = str.toCharArray();
    char p[] = password.toCharArray();
    int n = s.length;
    int m = p.length;

    for (int k=0; k<n; ++k) {
        int temp = s[k] + p[k%m];   
        s[k] = (char)temp;
    }
  System.out.println("1 : " + (int)s[0] + "  " +  s[0]);  // 输出：  1  :  169   ?
    str = new String(s);

    File file = new File("Test.txt");
    FileWriter fw = new FileWriter(file);
    fw.write(str);
    fw.flush();
    fw.close();

    FileReader fr = new FileReader(file);
    String sss = "";
    int b;
    while ((b=fr.read()) != -1) {
        System.out.println("2 : " + b + "  " + (char)b);  // 输出： 2 : 63  ?
        sss = sss + (char)b;
    }

    System.out.println("str : " + str);  // 输出： str : ?
    System.out.println("sss : " + sss); // 输出： sss : ?
    System.out.println(str.equals(sss)); // 输出： false
}
}