上机调试题:请说出E类中标注的【代码1】~【代码4】的输出结果。
import java.io.*;
public class E {
public static void main(String args]) {
int n = -1;
File f = new File("hello.txt");
byte] a = "abcd".getBytes();
try {
FileOutputStream out = new FileOutputStream(f);
out.write(a);
out.close();
FileInputStream in = new FileInputStream(f);
byte] tom = new byte3];
int m = in.read(tom, 0, 3);
System.out.println(m); //【代码1】
String s=new String(tom,0,3); System.out.println(s); //【代码2】
m = in.read(tom, 0, 3);
System.out.println(m); //【代码3】
s = new String(tom, 0, 3);
System.out.println(s); //【代码4】
} catch (IOException e) {
}
}
}