瓜娃之字符串分割，连接

Splitter.on(',')

.trimResults()

.omitEmptyStrings()

        .split(" foo, ,bar,");

用逗号分割，去掉结果两边的空格，忽略空字符串。

private static final Joiner JOINER = Joiner.on(", ").skipNulls();

private static final Joiner JOINER =Joiner.on(", ").useForNull(String);

JOINER.join("ffffffff","ddddd",null);