网上找的经纬度差距离计算

distance.java

public class t {
  public static void main ( String[] args ) {
		double earthRadius = 6371; //地球半径，单位km
		double lat1 = 31.215961;
		double lng1 = 121.456083;

		// 经纬度差0.000001 
		double lat2 = 31.215960;
		double lng2 = 121.456082;
		double dLat = Math.toRadians ( lat2 - lat1 );
		double dLng = Math.toRadians ( lng2 - lng1 );
		double a = Math.sin ( dLat / 2 ) * Math.sin ( dLat / 2 ) +
		           Math.cos ( Math.toRadians ( lat1 ) ) * Math.cos ( Math.toRadians ( lat2 ) ) *
		           Math.sin ( dLng / 2 ) * Math.sin ( dLng / 2 );
		double c = 2 * Math.atan2 ( Math.sqrt ( a ), Math.sqrt ( 1 - a ) );
		double dist = earthRadius * c;

		int meterConversion = 1609;

		System.out.println ( dist * 1000 ); // 距离！！！
		System.out.print ( new Float ( dist * meterConversion ).floatValue() );
	}
}