在一个老外的论坛上面看到一个算法(应该还有其他方法,这个不是最好的),做了一些修改,如下:import java.sql.*;
import java.util.*;
import java.io.*;
import java.text.*;
import java.lang.*;public class RandomTest {
Random rand = new Random(); private String randomnumber = ""; final String [] numset = {"0","1","2","3","4","5","6","7","8","9"}; public static void main(String[] args){
RandomTest test=new RandomTest();
for(int i=0;i<10;i++){
test.generateRandom();
System.out.println(test.getRandomNum());
}
} public String getRandomNum(){
return randomnumber;
} public void generateRandom () {
boolean isValidNum=false;
StringBuffer sb1 = new StringBuffer();
StringBuffer sb2 = new StringBuffer();
while(!isValidNum){
for(int n=0; n<13; n++){
sb2 = sb2.append(numset[rand.nextInt(10)]); }
randomnumber = sb1.append(sb2).toString();
//only get the random number can be parsed into integer
if(!randomnumber.startsWith("0")){
isValidNum=true;
}else{
//remember to remove the char in the buffer
sb1.delete(0,sb1.length());
sb2.delete(0,sb2.length());
}
}
}
}
import java.util.*;
import java.io.*;
import java.text.*;
import java.lang.*;public class RandomTest {
Random rand = new Random(); private String randomnumber = ""; final String [] numset = {"0","1","2","3","4","5","6","7","8","9"}; public static void main(String[] args){
RandomTest test=new RandomTest();
for(int i=0;i<10;i++){
test.generateRandom();
System.out.println(test.getRandomNum());
}
} public String getRandomNum(){
return randomnumber;
} public void generateRandom () {
boolean isValidNum=false;
StringBuffer sb1 = new StringBuffer();
StringBuffer sb2 = new StringBuffer();
while(!isValidNum){
for(int n=0; n<13; n++){
sb2 = sb2.append(numset[rand.nextInt(10)]); }
randomnumber = sb1.append(sb2).toString();
//only get the random number can be parsed into integer
if(!randomnumber.startsWith("0")){
isValidNum=true;
}else{
//remember to remove the char in the buffer
sb1.delete(0,sb1.length());
sb2.delete(0,sb2.length());
}
}
}
}
解决方案 »
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是不是100000000000-9999999999999
如果是的的话可以这样:
long reslut=long(Math.random()*(9999999999999-100000000000)+100000000000)