Java常用类、方法:Object、Scanner、String、StringBuffer、Arrays、Integer、Character
1、Object类
toString();
equals();
getClass();
finalize();
clone();
2、Scanner类
hasNextXxx();
nextXxx();
3、String类
contains();
isEmpty();
length();
charAt();
indexOf();
substring();
getBytes();
toCharArray();
valueOf();
toLowerOf();
toUpperOf();
concat();
replace();
trim();
compareTo();
compareToIgnoreCase();
4、StringBuffer类
append();
insert();
delete()
deleteCharAt();
replace();
reverse();
substring();
5、Arrays类
toString();
sort();
binartSearch();
6、Integer类
parseInt();
7、Character类
isUpperCase();
isLowerCase();
isDigit();
toUpper();
toLower();