第三周：正则表达式

使用正则表达式验证用户名

package com.citymango.regex;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class UsernameValidator {
private Pattern pattern;
private Matcher matcher;
private static final String USERNAME_PATTERN = "^[a-z0-9_-]{3,15}$";
public UsernameValidator() {
pattern = Pattern.compile(USERNAME_PATTERN);
}
/*使用正则表达式验证用户名
* @param username 用来验证的用户名
* @return 用户名有效返回true，无效则返回false
*/
public boolean validate(final String username){
matcher = pattern.matcher(username);
return matcher.matches();
}
}

使用正则表达式验证密码

package com.citymango.regex; 
import java.util.regex.Matcher; 
import java.util.regex.Pattern; 
public class PasswordValidator { 
private Pattern pattern; 
private Matcher matcher; 
private static final String PASSWORD_PATTERN = 
"((?=.*\\d)(?=.*[a-z])(?=.*[A-Z])(?=.*[@#$%]).{6,20})"; 
public PasswordValidator() { 
pattern = Pattern.compile(PASSWORD_PATTERN); 
} 
public boolean validate(final String password) { 
matcher = pattern.matcher(password); 
return matcher.matches(); 
} 
}