生成隨機數值方法

//生成隨機數值方法一：
/**
*生成隨機碼
*pwd_len 密碼長度
*/
public static String genRandomNum(int pwd_len){
//35是因為數組是從0開始的，26個字母+10個數字
final int maxNum=36;
int i;//生成的隨機數
int count=0;//生成的密碼長度
char[] str={'a',''b,'c','d','e','f','g','h','i','j','k','l','m','n',
'o','p',q','r','s','t','u','v','w','y','z',
'0','1','2','3','4','5','6','7','8','9'};

StringBuffer pwd=new StringBuffer("");
Random r=new Random();
while(count<pwd_len){
//生成的隨機數，去絕對值，防止生成負數
i=Math.abs(r.nexInt(maxNum));//生成的數最大為36-1
if(i>0 && i<str.length){
pwd.append(str[i]);
count++;
}
}
return pwd.toString();
}

 

//生成隨機數值方法二：
Random r = new Random();
rdGet=Math.abs(r.nextInt())%26+97; //产生97到122的随机数(a-z的键位值)
rdGetA_Z=Math.abs(r.nextInt())%26+65; //产生97到122的随机数(A-Z的键位值)
char num1=(char)rdGet;
String dd=Character.toString(num1);

 

//生成隨機數值方法三：
//生成4位數隨機數值

Random r = new Random();
String verifyCode = Integer.toString(r.nextInt(RANDOM))
+ Integer.toString(r.nextInt(RANDOM))
+ Integer.toString(r.nextInt(RANDOM))
+ Integer.toString(r.nextInt(RANDOM));

 

//生成隨機數值方法四：

Random random= new Random();

int len=8;

String  text="";

 

for ( int i = 1; i <= len; i++ ) {
String rand = null ;
rand = String.valueOf( ( char )(random.nextInt(10) + 48 ) );
text += rand ;
}