java中Scanner的hasNext()的疑问

请问下面代码有什么区别，该如何输入才能使第一段代码不满足条件而跳出循环？

Scanner s = new Scanner(System.in);        while(s.hasNext())        {            System.out.println(s.next());        }

Scanner s = new Scanner(System.in);        while(true)        {            System.out.println(s.next());        }

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。

import java.util.Scanner;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());        }    }}

hasNext()方法会阻塞，不代表next()方法就不会阻塞,我们看源码。

/** * 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 * <code>true</code>. * * @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（在myeclipse编译器中也是如此操作）。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。