Java随机密码生成器，Java随机生成长度不少于6的指定长度的密码，且这个字符串必须包含大小写字母、数字和特殊字符，四种的任意三种

import java.util.Random ;

public class RandomPassword {

public static void main ( String [] args ) {

String password = getRandomPassword ( 8 );

System . out . println ( password );

}

//获取验证过的随机密码

public static String getRandomPassword ( int len ) {

String result = null ;

/*if(len >= 6) {

for(result = makeRandomPassword(len);len >= 6;result = makeRandomPassword(len)){

if (result.matches(".*[a-z]{1,}.*") && result.matches(".*[A-Z]{1,}.*") && result.matches(".*\\d{1,}.*") && result.matches(".*[~!@#$%^&*\\.?]{1,}.*")) {

return result;

}

}

}*/

while ( len >= 6 ){

result = makeRandomPassword ( len );

if ( result . matches ( ".*[a-z]{1,}.*" ) && result . matches ( ".*[A-Z]{1,}.*" ) && result . matches ( ".*\\d{1,}.*" ) && result . matches ( ".*[~!@#$%^&*\\.?]{1,}.*" )) {

return result ;

}

result = makeRandomPassword ( len );

}

return "长度不得少于6位!" ;

}

//随机密码生成

public static String makeRandomPassword ( int len ){

char charr [] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890~!@#$%^&*.?" . toCharArray ();

//System.out.println("字符数组长度:" + charr.length); //可以看到调用此方法多少次

StringBuilder sb = new StringBuilder ();

Random r = new Random ();

for ( int x = 0 ; x < len ; ++ x ) {

sb . append ( charr [ r . nextInt ( charr . length )]);

}

return sb . toString ();

}

}