正则表达式问题
如何匹配 <META KEY > key 只能出现一次

[解决办法]
String regStr = "^.* <META (KEY){1}> .*$ ";
String str = " <META KEY> ";
if(str.matches(regStr)){
System.out.println( "true ");
}else{
System.out.println( "false ");
}