【The Java™ Tutorials】【Regular Expressions】4. Character classes
ConstructDescription[abc]a,b,orc(simpleclass)[^abc]Anycharacterexcepta,b,orc(negation)[a-zA-Z]athroughz,orAthroughZ,inclusive(range)[a-d[m-p]]athroughd,ormthroughp:[a-dm-p](union)[a-z&&[def]]d,e,orf(i