The most complete Java random number generation algorithm in history sharing _java

Copy Code code as follows:

String Password = randomutil.generatestring (10);

The source code is as follows:

Copy Code code as follows:

Package com.javaniu.core.util;
Import Java.util.Random;
public class Randomutil {
public static final String Allchar = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
public static final String Letterchar = "ABCDEFGHIJKLLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZ";
public static final String Numberchar = "0123456789";

 /**
  * Returns a fixed-length random string (contains only uppercase and lowercase letters, numbers)
  *
  * @param length
  *             random string length
  * @return Random string
  */
  public static String generatestring (int length) {
  stringbuffer sb = new StringBuffer ();
  random Random = new Random ();
  for (int i = 0; i < length; i++) {
   sb.append (Allchar.charat random.nextint ( Allchar.length ()));
  }
  return sb.tostring ();
 }

/**
* Returns a fixed-length random plain letter string (containing only uppercase and lowercase letters)
*
* @param length
* Random string length
* @return Random string
*/
public static String generatemixstring (int length) {
StringBuffer sb = new StringBuffer ();
Random Random = new Random ();
for (int i = 0; i < length; i++) {
Sb.append (Allchar.charat (Random.nextint (Letterchar.length ()));
}
return sb.tostring ();
}

/**
* Returns a fixed-length random plain capital string (containing only uppercase and lowercase letters)
*
* @param length
* Random string length
* @return Random string
*/
public static String generatelowerstring (int length) {
return generatemixstring (length). toLowerCase ();
}

/**
* Returns a fixed-length random plain lowercase letter string (contains only uppercase and lowercase letters)
*
* @param length
* Random string length
* @return Random string
*/
public static String generateupperstring (int length) {
return generatemixstring (length). toUpperCase ();
}

/**
* Generate a fixed-length pure 0 string
*
* @param length
* String length
* @return Pure 0 string
*/
public static String generatezerostring (int length) {
StringBuffer sb = new StringBuffer ();
for (int i = 0; i < length; i++) {
Sb.append (' 0 ');
}
return sb.tostring ();
}

 /**
  * Generates a fixed-length string based on numbers, not enough for front 0
  *
  * @param num
  *             Digital
  * @param fixdlenth
  *             string Length
  * @return Fixed length string
  */
 public Static String tofixdlengthstring (long num, int fixdlenth) {
  stringbuffer sb = new StringBuffer ();
  string strnum = string.valueof (num);
  if (fixdlenth-strnum.length () >= 0) {
   sb.append generatezerostring ( Fixdlenth-strnum.length ()));
  } else {
   throw new RuntimeException (convert number + num + to length to + fixdlenth
 & Nbsp;   + "string has an exception! ");
  }
  sb.append (Strnum);
  return sb.tostring ();
 }

 /**
  * The number of Len digits generated each time is different
  *
  * @param param
  * @return Fixed-length number
  */
& nbsp;public static int getnotsimple (int[] param, int len) {
  random rand = new Random ();
  for (int i = param.length i > 1; i--) {
   int index = rand.nextint (i);
   int tmp = Param[index];
   param[index] = param[i-1];
   param[i-1] = tmp;
  }
  int result = 0;
  for (int i = 0; i < len; i++) {
   result = result * + param[i];
&NBSP;&NBSP}
  return result;
 .}

public static void Main (string[] args) {
System.out.println ("Returns a fixed-length random string (containing only uppercase and lowercase letters, numbers):" + generatestring (10));
System.out
. println ("Returns a fixed-length random plain letter string (containing only uppercase and lowercase letters):" + generatemixstring (10));
System.out.println ("Returns a fixed-length random plain capital string (containing only uppercase and lowercase letters):"
+ generatelowerstring (10));
System.out.println ("Returns a fixed-length random pure lowercase letter string (containing only uppercase and lowercase letters):"
+ generateupperstring (10));
System.out.println ("Generate a fixed-length pure 0 string:" + generatezerostring (10));
SYSTEM.OUT.PRINTLN ("Generates a fixed-length string from a number that is not long enough to fill 0 in front:"
+ tofixdlengthstring (123, 10));
Int[] in = {1, 2, 3, 4, 5, 6, 7};
System.out.println ("The number of Len digits per generation is different:" + getnotsimple (in, 3));
}
}

There is a picture of the truth:

Java Random character Supplemental Edition

Today in Zuidaimai to see a Java random character generation demo, just need to use, but found incomplete, to reorganize, to share to the needy friends

Copy Code code as follows:

public static void Main (string[] args) {
String s = randomnum.getrandomnumstr (5);
System.out.println (s);
System.out.println ("Generate 5 strings containing 5 characters:");
Randomnum.suijizifuchuan (5,5);
System.out.println ("Generate 3 strings containing 6 characters:");
Randomnum.suijizifuchuan (6,3);
SYSTEM.OUT.PRINTLN ("Generate any 1 to 20 strings containing any 1 to 10 characters:");
Randomnum.suijizifuchuan ((int) (20*math.random ()), (int) (10*math.random ()));
SYSTEM.OUT.PRINTLN ("Random generation Character:");
int i=0;
while (i< (int) (10*math.random ()) {
Randomnum.suijizifuchuan ((int) (20*math.random ()), 1);
i++;
}
}

public static void Suijizifuchuan (int x,int y) {
for (int j=0;j<y;j++) {
for (int i=0;i<x;i++) {
int a= (int) (100*math.random () +100*math.random ());
while (true) {
if (a>96&a<123)
Break
Else
a= (int) (100*math.random () +100*math.random ());
}
System.out.print ((char) a);
}
System.out.println ();
}
}

Execution results:



Source: http://www.zuidaima.com/share/ 1585762703215616.htm