import java.util.Random;
public class RandomPassword {
private int length = 8; // password length
private int numLen = 2; // count of numbers
private int nonABNumLen = 1;// count of special character
/**
* get an alphabeta
* @return
*/
private char getAB() {
Random rand = new Random();
int ri = rand.nextInt(52);
char c = 0;
if (ri < 26) {
c = (char) (65 + ri);
} else {
c = (char) (97 + ri - 26);
}
return c;
}
/**
* get a num
* @return
*/
private char getNum() {
Random rand = new Random();
int ri = rand.nextInt(10);
char c = (char) (48 + ri);
return c;
}
/**
* get a non num / non abc char
* @return
*/
private char getNonABNum() {
Random rand = new Random();
int total = (47 - 32) + (64 - 57) + (96 - 90) + (126 - 122); //total nonABNUM characters
int ri = rand.nextInt(total);
char c = 0;
if (ri < (47 - 32)) {
c = (char) (ri + 32 + 1);
} else if (ri < (47 - 32)+(64 - 57)) {
c = (char) (ri - (47 - 32) + 57 + 1);
} else if (ri < (47 - 32)+(64 - 57) + (96 - 90)) {
c = (char) (ri - (47 - 32) -(64 - 57) + 90 + 1 );
} else {
c = (char) (ri - (47 - 32) -(64 - 57) - (96 - 90) + 122 + 1 );
}
return c;
}
/**
* Generate the password chars array
*/
public String password() {
char[] pwd = new char[length];
// generate the pwd chars
for (int i = 0; i < length; i++ ) {
if (i < length -numLen -nonABNumLen) {
pwd[i] = getAB();
} else if (i < length -nonABNumLen ) {
pwd[i] = getNum();
} else {
pwd[i] = getNonABNum();
}
}
// randomly shuffle pwd char array - Fisher–Yates shuffle
Random rand = new Random();
for (int i = length - 1; i > 0; i --) {
int j = rand.nextInt(i + 1);
// swap char[i] and char[j]
char c = pwd[j];
pwd[j] = pwd[i];
pwd[i] = c;
}
return new String(pwd);
}
/**
* Test
* @param args
*/
public static void main(String[] args) {
RandomPassword rp = new RandomPassword ();
for (int i = 0; i< 20; i++) {
System.out.println ("Random Password: " + rp.password());
}
}
}
某次运行结果：
Random Password: "f1iiu9E Random Password: X:9LT9UX Random Password: BO7CQ'U4 Random Password: Esp^N00r Random Password: f51BpT^D Random Password: d2)mRPy0 Random Password: m0Ww^8aa Random Password: FwV)RQ22 Random Password: 1_9hRtSt Random Password: Q9m1YMM= Random Password: 7cN#Jo7o Random Password: 3oa7s^OO Random Password: i(OB6Xz8 Random Password: VL6h2z^j Random Password: (eVqu9p9 Random Password: ~DGGS80o Random Password: [2lp4xlL Random Password: #vs0sHv9 Random Password: Lp0XX2]L Random Password: (POo9jC7