文件E.java的长度是51个字节，请说出E类中标注的【代码1】，【代码2】,【代码3】的输出结果。
import java.io.;
public class E {
public static void main(String args[]) {
File f = new File("E.java");
try{ RandomAccessFile in = new RandomAccessFile(f,"rw");
System.out.println(f.length()); //【代码1】
FileOutputStream out = new FileOutputStream(f);
System.out.println(f.length()); //【代码2】
}
catch(IOException e) {
System.out.println("File read Error"+e);
}
}
}
2．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 byte[3];
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);
}
catch(IOException e) {}
}
}