Guava CharMatcher

    @Test    public void testRemoveWhiteSpaceUsingRegexp() {        String s = " first   dfgdfgdsfas  ";        String expectedString = "firstdfgdfgdsfas";        String target = s.replaceAll(" +","");        assertThat(target, is(expectedString));    }

@Test    public void testRemoveWhiteSpaceUsingCharMatcher() {        String s = "first   dfgdfgdsfas  ";        String expectedString = "firstdfgdfgdsfas";        String target = CharMatcher.WHITESPACE.removeFrom(s);        assertThat(target, is(expectedString));    }

以上是通过正则表带式匹配替换空格和通过CharMatcher删除空格的不同实现的对比。

Guava CharMatcher的介绍： http://www.cnblogs.com/zemliu/p/3345087.html