创建UUID。

String uniqueID = UUID.randomUUID().toString();

创建UUID。

String uniqueID = UUID.randomUUID().toString();

这为UUID生成增加了更多的随机性，但确保每个生成的id都具有相同的长度

import org.apache.commons.codec.digest.DigestUtils;
import java.util.UUID;

public String createSalt() {
    String ts = String.valueOf(System.currentTimeMillis());
    String rand = UUID.randomUUID().toString();
    return DigestUtils.sha1Hex(ts + rand);
}

具有计数信息的唯一ID

import java.util.concurrent.atomic.AtomicLong;

public class RandomIdUtils {

    private static AtomicLong atomicCounter = new AtomicLong();

    public static String createId() {

        String currentCounter = String.valueOf(atomicCounter.getAndIncrement());
        String uniqueId = UUID.randomUUID().toString();

        return uniqueId + "-" + currentCounter;
    }
}

java.util.UUID: toString()

在java中有三种生成唯一id的方法。

1) UUID类提供了一种生成唯一id的简单方法。

 UUID id = UUID.randomUUID();
 System.out.println(id);

2) securerrandom和MessageDigest

//initialization of the application
 SecureRandom prng = SecureRandom.getInstance("SHA1PRNG");

//generate a random number
 String randomNum = new Integer(prng.nextInt()).toString();

//get its digest
 MessageDigest sha = MessageDigest.getInstance("SHA-1");
 byte[] result =  sha.digest(randomNum.getBytes());

System.out.println("Random number: " + randomNum);
System.out.println("Message digest: " + new String(result));

3)使用java.rmi.server.UID

UID userId = new UID();
System.out.println("userId: " + userId);