在Android中获取网络时间，我们需要使用 NTP (Network Time Protocol)协议，我们可以使用第三方的库或者自己来实现。下面是一种自己实现的方法。
代码如下：
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
public class SNTPClient {
private static final int UDP_PORT = 123;
private static final String TIME_SERVER = "time.nist.gov";
private static final int TIMEOUT = 3000;
public long fetchNetworkTime() {
try {
DatagramSocket socket = new DatagramSocket();
socket.setSoTimeout(TIMEOUT);
InetAddress address = InetAddress.getByName(TIME_SERVER);
byte[] buffer = new byte[48];
DatagramPacket packet = new DatagramPacket(buffer, buffer.length, address, UDP_PORT);
// Craft NTP request packet
buffer[0] = 0b00100011; // LI, Version, Mode
long requestTime = System.currentTimeMillis();
// Send NTP request packet
socket.send(packet);
// Wait for response
socket.receive(packet);
long responseTime = System.currentTimeMillis();
// Parse NTP Response
long originateTime = parseTimestamp(buffer, 24);
long receiveTime = parseTimestamp(buffer, 32);
long transmitTime = parseTimestamp(buffer, 40);
// Calculate delay & offset
long roundTripDelay = responseTime - requestTime - (transmitTime - receiveTime);
long timeOffset = ((receiveTime - originateTime) + (transmitTime - requestTime)) / 2;
return System.currentTimeMillis() + timeOffset;
} catch (Exception e) {
e.printStackTrace();
return System.currentTimeMillis();
}
}
private long parseTimestamp(byte[] buffer, int index) {
long seconds = 0;
for (int i = 0; i < 4; i++) {
seconds = (seconds << 8) | (buffer[index + i] & 0xFF);
}
long fractions = 0;
for (int i = 4; i < 8; i++) {
fractions = (fractions << 8) | (buffer[index + i] & 0xFF);
}
return (seconds - 2208988800L) * 1000 + fractions * 1000L / 0x100000000L;
}
}以上是一种使用Java原生socket的方式来获取网络时间的代码示例，其中最关键的是通过构造一个NTP请求包发送给NTP服务器，然后解析服务器返回的response包来看网络时间。
注意：这里需要申请网络权限, 在manifest中添加：
<uses-permission android:name="android.permission.INTERNET" />发布者：luotuoemo，转转请注明出处：https://www.jintuiyun.com/172525.html
