android获得北京时间的源码

以下,为获得北京时间的代码;

private void getNewTiem() {        new Thread(){            @Override            public void run() {                super.run();                SntpClient client2 = new SntpClient();                if (client2.requestTime("cn.pool.ntp.org", 30000)) {                    long now = client2.getNtpTime() + System.currentTimeMillis() / 1000                            - client2.getNtpTimeReference();                    Date current = new Date(now);                    System.out.println(current.toString());                    Log.d(TAG,"client2.getNtpTime()=" + new Date(client2.getNtpTime()).toString() );                }else{                    Log.d(TAG,"error=timeout");                }            }        }.start();    }    class SntpClient {        private static final int ORIGINATE_TIME_OFFSET = 24;        private static final int RECEIVE_TIME_OFFSET = 32;        private static final int TRANSMIT_TIME_OFFSET = 40;        private static final int NTP_PACKET_SIZE = 48;        private static final int NTP_PORT = 123;        private static final int NTP_MODE_CLIENT = 3;        private static final int NTP_VERSION = 3;        // Number of seconds between Jan 1, 1900 and Jan 1, 1970        // 70 years plus 17 leap days        private static final long OFFSET_1900_TO_1970 = ((365L * 70L) + 17L) * 24L * 60L * 60L;        // system time computed from NTP server response        private long mNtpTime;        // value of SystemClock.elapsedRealtime() corresponding to mNtpTime        private long mNtpTimeReference;        // round trip time in milliseconds        private long mRoundTripTime;        /**         * Sends an SNTP request to the given host and processes the response.         *         * @param host         *            host name of the server.         * @param timeout         *            network timeout in milliseconds.         * @return true if the transaction was successful.         */        public boolean requestTime(String host, int timeout) {            try {                DatagramSocket socket = new DatagramSocket();                socket.setSoTimeout(timeout);                InetAddress address = InetAddress.getByName(host);                byte[] buffer = new byte[NTP_PACKET_SIZE];                DatagramPacket request = new DatagramPacket(buffer, buffer.length,                        address, NTP_PORT);                // set mode = 3 (client) and version = 3                // mode is in low 3 bits of first byte                // version is in bits 3-5 of first byte                buffer[0] = NTP_MODE_CLIENT | (NTP_VERSION << 3);                // get current time and write it to the request packet                long requestTime = System.currentTimeMillis();                long requestTicks = System.nanoTime() / 1000;                writeTimeStamp(buffer, TRANSMIT_TIME_OFFSET, requestTime);                socket.send(request);                // read the response                DatagramPacket response = new DatagramPacket(buffer, buffer.length);                socket.receive(response);                long responseTicks = System.nanoTime() / 1000;                long responseTime = requestTime + (responseTicks - requestTicks);                socket.close();                // extract the results                long originateTime = readTimeStamp(buffer, ORIGINATE_TIME_OFFSET);                long receiveTime = readTimeStamp(buffer, RECEIVE_TIME_OFFSET);                long transmitTime = readTimeStamp(buffer, TRANSMIT_TIME_OFFSET);                long roundTripTime = responseTicks - requestTicks                        - (transmitTime - receiveTime);                // receiveTime = originateTime + transit + skew                // responseTime = transmitTime + transit - skew                // clockOffset = ((receiveTime - originateTime) + (transmitTime -                // responseTime))/2                // = ((originateTime + transit + skew - originateTime) +                // (transmitTime - (transmitTime + transit - skew)))/2                // = ((transit + skew) + (transmitTime - transmitTime - transit +                // skew))/2                // = (transit + skew - transit + skew)/2                // = (2 * skew)/2 = skew                long clockOffset = ((receiveTime - originateTime) + (transmitTime - responseTime)) / 2;                // if (Config.LOGD) Log.d(TAG, "round trip: " + roundTripTime +                // " ms");                // if (Config.LOGD) Log.d(TAG, "clock offset: " + clockOffset +                // " ms");                // save our results - use the times on this side of the network                // latency                // (response rather than request time)                mNtpTime = responseTime + clockOffset;                mNtpTimeReference = responseTicks;                mRoundTripTime = roundTripTime;            } catch (Exception e) {                return false;            }            return true;        }        /**         * Returns the time computed from the NTP transaction.         *         * @return time value computed from NTP server response.         */        public long getNtpTime() {            return mNtpTime;        }        /**         * Returns the reference clock value (value of         * SystemClock.elapsedRealtime()) corresponding to the NTP time.         *         * @return reference clock corresponding to the NTP time.         */        public long getNtpTimeReference() {            return mNtpTimeReference;        }        /**         * Returns the round trip time of the NTP transaction         *         * @return round trip time in milliseconds.         */        public long getRoundTripTime() {            return mRoundTripTime;        }        /**         * Reads an unsigned 32 bit big endian number from the given offset in the         * buffer.         */        private long read32(byte[] buffer, int offset) {            byte b0 = buffer[offset];            byte b1 = buffer[offset + 1];            byte b2 = buffer[offset + 2];            byte b3 = buffer[offset + 3];            // convert signed bytes to unsigned values            int i0 = ((b0 & 0x80) == 0x80 ? (b0 & 0x7F) + 0x80 : b0);            int i1 = ((b1 & 0x80) == 0x80 ? (b1 & 0x7F) + 0x80 : b1);            int i2 = ((b2 & 0x80) == 0x80 ? (b2 & 0x7F) + 0x80 : b2);            int i3 = ((b3 & 0x80) == 0x80 ? (b3 & 0x7F) + 0x80 : b3);            return ((long)i0 << 24) + ((long)i1 << 16) + ((long)i2 << 8) + (long)i3;        }        /**         * Reads the NTP time stamp at the given offset in the buffer and returns it         * as a system time (milliseconds since January 1, 1970).         */        private long readTimeStamp(byte[] buffer, int offset) {            long seconds = read32(buffer, offset);            long fraction = read32(buffer, offset + 4);            return ((seconds - OFFSET_1900_TO_1970) * 1000)                    + ((fraction * 1000L) / 0x100000000L);        }        /**         * Writes system time (milliseconds since January 1, 1970) as an NTP time         * stamp at the given offset in the buffer.         */        private void writeTimeStamp(byte[] buffer, int offset, long time) {            long seconds = time / 1000L;            long milliseconds = time - seconds * 1000L;            seconds += OFFSET_1900_TO_1970;            // write seconds in big endian format            buffer[offset++] = (byte) (seconds >> 24);            buffer[offset++] = (byte) (seconds >> 16);            buffer[offset++] = (byte) (seconds >> 8);            buffer[offset++] = (byte) (seconds >> 0);            long fraction = milliseconds * 0x100000000L / 1000L;            // write fraction in big endian format            buffer[offset++] = (byte) (fraction >> 24);            buffer[offset++] = (byte) (fraction >> 16);            buffer[offset++] = (byte) (fraction >> 8);            // low order bits should be random data            buffer[offset++] = (byte) (Math.random() * 255.0);        }    }

公司要求,要用到北京时间;

网络上有很多类似的写法,但是这个写法亲测无误,注意这个时间与北京时间误差大概在1分钟左右;

若有源码,请采用

import android.net.SntpClient;

的方法导入;

4月28日更新：

追加三个获取时间的服务器。亲测可行；

"time.windows.com",// Microsoft"time.apple.com",  // apple.com by us"time.asia.apple.com",// apple.com by asia