UUID生成随机数和时间戳
对UUID产生的随机数进行处理
对UUID生成的时间戳进行不同的输出
代码
public class DateTime {public static void main(String[] args) {String uuid1 = UUID.randomUUID().toString();//生成UUIDSystem.out.println("uuid1 默认的uuid: " + uuid1);String uuid2 = UUID.randomUUID().toString().replace("-", "");//格式化UUID将“-”去掉System.out.println("uuid2 将“-”去掉:" + uuid2);String uuid3 = UUID.randomUUID().toString().replace("-", ".");//格式UUID将“-”格式成“.”System.out.println("uuid3 将“-”格式成“.”: " + uuid3);String uuid4 = UUID.randomUUID().toString().concat(".apk");//格式UUID,在UUID的结尾添加.apkSystem.out.println("uuid4 结尾添加.apk: " + uuid4);String uuid5 = UUID.randomUUID().toString().replaceAll("\\d", "");//替换所有,参数1为要替换的字符正则表达式,参数2为替换字符；System.out.println("uuid5 去掉所有数字: " + uuid5);UUID newuuid = UUID.fromString(uuid1);//将String类型 转成 UUIDUUID u1 = UUID.randomUUID();UUID u2 = UUID.randomUUID();int values = pareTo(u2); // -1=小于 0=等于 1=大于System.out.println("u1 对比 u2: " + values);System.out.println("IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII");Date date = new Date();System.out.println("当前时间=" + date);long date2 = System.currentTimeMillis();System.out.println("毫秒级time值=" + date2);Calendar instance = Calendar.getInstance();long time3 = instance.getTimeInMillis();System.out.println("第三种获取时间的方式" + time3);long datetime = System.currentTimeMillis();SimpleDateFormat formatter = new SimpleDateFormat("dd-MMM-yyyy");String format = formatter.format(datetime);System.out.println("格式化后的时间" + format);}}
运行结果
uuid1 默认的uuid: 9b1de6c9-bccf-43f1-9060-9c2da1b910ccuuid2 将“-”去掉:1bdb28c966c644de97fb509bd044eb57uuid3 将“-”格式成“.”: cc02df9c.41df.45fe.9477.e86c0c9fc948uuid4 结尾添加.apk: bef69749-2ed1-4505-93a7-ea14321ecb3b.apkuuid5 去掉所有数字: daf-a-c-b-aeeeu1 对比 u2: 1IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII当前时间=Thu Nov 21 22:49:33 CST 毫秒级time值=1574347773558第三种获取时间的方式1574347773560格式化后的时间21-十一月-
