第一个问题，两段代码的区别在于阻塞的位置不同，加上一行输出代码就可以很明显地看到差别。

public class Test {

public static void main(String[] args) {

Scanner s = new Scanner(System.in);

while(s.hasNext())

{

System.out.print("You inputted: ");

System.out.println(s.next());

}

}

}

另，hasNext()方法会阻塞，不代表next()方法就不会阻塞。

/**

* Returns true if this scanner has another token in its input.

* This method may block while waiting for input to scan.

* The scanner does not advance past any input.

*

* @return true if and only if this scanner has another token

* @throws IllegalStateException if this scanner is closed

* @see java.util.Iterator

*/

public boolean hasNext() {

ensureOpen();

saveState();

while (!sourceClosed) {

if (hasTokenInBuffer())

return revertState(true);

readInput();

}

boolean result = hasTokenInBuffer();

return revertState(result);

}

/**

* Finds and returns the next complete token from this scanner.

* A complete token is preceded and followed by input that matches

* the delimiter pattern. This method may block while waiting for input

* to scan, even if a previous invocation of {@link #hasNext} returned

* true.

*

* @return the next token

* @throws NoSuchElementException if no more tokens are available

* @throws IllegalStateException if this scanner is closed

* @see java.util.Iterator

*/

public String next() {

ensureOpen();

clearCache

while (true) {

String token = getCompleteTokenInBuffer(null);

if (token != null) {

matchValid = true;

skipped = false;

return token;

}

if (needInput)

readInput();

else

throwFor();

}

}

第二个问题，想要结束循环，在Windows环境下，需要输入Ctrl+Z；而在Unix环境下，需要输入Ctrl+D。注意，这是输入，而不是对控制台进行操作。这相当于向控制台输入一个字符，这个字符代表EOF，此时hasNext()方法返回false，循环结束。