1.
public static void main(String[] args) {
System.out.println(getEmailSuffix("[email protected]")); // 163.com
System.out.println(getEmailSuffix("@qq.com")); //qq.com
}
private static String getEmailSuffix(String email) {
email = defaultIfBlank(email,"").trim();
if (!email.isEmpty()) {
int index = email.indexOf('@') + 1;
if (index < email.length()) {
return email.substring(index).toLowerCase();
}
}
return "";
}
public static <T extends CharSequence> T defaultIfBlank(final T str, final T defaultStr) {
return isBlank(str) ? defaultStr : str;
}
public static boolean isBlank(final CharSequence cs) {
int strLen;
if (cs == null || (strLen = cs.length()) == 0) {
return true;
}
for (int i = 0; i < strLen; i++) {
if (!Character.isWhitespace(cs.charAt(i))) {
return false;
}
}
return true;
}
}
2. 优化，封装到一个公用的字符串操作类中去
public static String getEmailSuffix(String email) {
email = MyStringUtils.defaultIfBlank(email,"").trim();
if (!email.isEmpty()) {
int index = email.indexOf('@') + 1;
if (index < email.length()) {
return email.substring(index).toLowerCase();
}
}
return "";
}
//自己封装的字符串操作类
class MyStringUtils {
public static <T extends CharSequence> T defaultIfBlank(final T str, final T defaultStr) {
return isBlank(str) ? defaultStr : str;
}
public static boolean isBlank(final CharSequence cs) {
int strLen;
if (cs == null || (strLen = cs.length()) == 0) {
return true;
}
for (int i = 0; i < strLen; i++) {
if (!Character.isWhitespace(cs.charAt(i))) {
return false;
}
}
return true;
}
public static boolean isNotBlank(final CharSequence cs) {
return !isBlank(cs);
}
public static String defaultString(Object obj) {
return obj == null ? "" : obj.toString();
}
}