JAVA calculates the distance between two longitudes and latitudes

One: Inverse cosine calculation method

1.1 : Tools

The distance can be calculated directly without relying on external jars. DistanceUtil.java

package com.utils;

import java.math.BigDecimal;

public class DistanceUtil {
    
    

    //平均半径,单位：m；不是赤道半径。赤道为6378左右
    private static final double EARTH_RADIUS = 6371000;

    public static BigDecimal getDistanceBigDecimalOneDecimalPlace(BigDecimal lat1, BigDecimal lng1, BigDecimal lat2, BigDecimal lng2) {
    
    
        return getDistanceBigDecimal(lat1, lng1, lat2, lng2).setScale(1, BigDecimal.ROUND_HALF_UP);
    }

    public static BigDecimal getDistanceBigDecimal(BigDecimal lat1, BigDecimal lng1, BigDecimal lat2, BigDecimal lng2) {
    
    
        //经纬度（角度）转弧度。弧度用作参数，以调用Math.cos和Math.sin
        BigDecimal radiansAX = new BigDecimal(Math.toRadians(lng1.doubleValue()));//A经弧度
        BigDecimal radiansAY = new BigDecimal(Math.toRadians(lat1.doubleValue()));//A纬弧度
        BigDecimal radiansBX = new BigDecimal(Math.toRadians(lng2.doubleValue()));//B经弧度
        BigDecimal radiansBY = new BigDecimal(Math.toRadians(lat2.doubleValue()));//B纬弧度
        //公式中“cosβ1cosβ2cos（α1-α2）+sinβ1sinβ2”的部分，得到∠AOB的cos值
        BigDecimal cos =  new BigDecimal(Math.cos(radiansAY.doubleValue()) * Math.cos(radiansBY.doubleValue()) * Math.cos(radiansAX.doubleValue() - radiansBX.doubleValue())
                + Math.sin(radiansAY.doubleValue()) * Math.sin(radiansBY.doubleValue()));
//        log.info("cos = " + cos);//值域[-1,1]
        BigDecimal acos = new BigDecimal(Math.acos(cos.doubleValue()));//反余弦值
//        log.info("acos = " + acos);//值域[0,π]
//        log.info("∠AOB = " + Math.toDegrees(acos));//球心角 值域[0,180]
        return new BigDecimal(EARTH_RADIUS).multiply(acos);//最终结果
    }

    public static double getDistanceDouble(Double lat1, Double lng1, Double lat2, Double lng2) {
    
    
        //经纬度（角度）转弧度。弧度用作参数，以调用Math.cos和Math.sin
        double radiansAX = Math.toRadians(lng1);//A经弧度
        double radiansAY = Math.toRadians(lat1);//A纬弧度
        double radiansBX = Math.toRadians(lng2);//B经弧度
        double radiansBY = Math.toRadians(lat2);//B纬弧度
        //公式中“cosβ1cosβ2cos（α1-α2）+sinβ1sinβ2”的部分，得到∠AOB的cos值
        double cos = Math.cos(radiansAY) * Math.cos(radiansBY) * Math.cos(radiansAX - radiansBX) + Math.sin(radiansAY) * Math.sin(radiansBY);
//        log.info("cos = " + cos);//值域[-1,1]
        double acos = Math.acos(cos);//反余弦值
//        log.info("acos = " + acos);//值域[0,π]
//        log.info("∠AOB = " + Math.toDegrees(acos));//球心角 值域[0,180]
        return EARTH_RADIUS * acos;//最终结果
    }

    public static void main(String[] args) {
    
    
        System.out.println("距离" + getDistanceDouble(31.22814, 121.400136,31.229016, 121.398455)  + "米");
        System.out.println("距离" + getDistanceBigDecimal(new BigDecimal("31.22814"), new BigDecimal("121.400136"),
                new BigDecimal("31.229016"), new BigDecimal("121.398455"))  + "米");
        System.out.println("距离" + getDistanceBigDecimalOneDecimalPlace(new BigDecimal("31.22814"), new BigDecimal("121.400136"),
                new BigDecimal("31.229016"), new BigDecimal("121.398455"))  + "米");
    }

}

1.2 : Verification

Which method to use (BigDecimal, double) can be judged according to the precision.
The specific number of reserved bits can be set by yourself when using it.

Two: Use third-party jar

2.1 : Add dependencies

Add third-party jar packages.

<!-- 计算两经纬度之间的距离 -->
<dependency>
    <groupId>org.gavaghan</groupId>
    <artifactId>geodesy</artifactId>
    <version>1.1.3</version>
</dependency>

2.2 : Tools

Directly use the tools in the third-party jar package for calculation. DistanceUtil.java

package com.utils;

import org.gavaghan.geodesy.Ellipsoid;
import org.gavaghan.geodesy.GeodeticCalculator;
import org.gavaghan.geodesy.GeodeticCurve;
import org.gavaghan.geodesy.GlobalCoordinates;
import java.math.BigDecimal;

public class DistanceUtil {
    
    

    public static double getDistanceMeter(GlobalCoordinates gpsFrom, GlobalCoordinates gpsTo, Ellipsoid ellipsoid) {
    
    
        //创建GeodeticCalculator，调用计算方法，传入坐标系、经纬度用于计算距离
        GeodeticCurve geoCurve = new GeodeticCalculator().calculateGeodeticCurve(ellipsoid, gpsFrom, gpsTo);
        return geoCurve.getEllipsoidalDistance();
    }

    public static void main(String[] args) {
    
    
        GlobalCoordinates source = new GlobalCoordinates(31.22814, 121.400136);
        GlobalCoordinates target = new GlobalCoordinates(31.229016, 121.398455);
        double meter1 = getDistanceMeter(source, target, Ellipsoid.Sphere);
        double meter2 = getDistanceMeter(source, target, Ellipsoid.WGS84);
        System.out.println("Sphere坐标系计算结果：" + meter1 + "米");
        System.out.println("WGS84 坐标系计算结果：" + meter2 + "米");

    }

}

2.3 : Verification

Three: Summary

Comparing the results together, you will find that the third-party jar, Sphere is more accurate.
If you don't want to introduce jar, it is recommended to use directly: arc cosine calculation method.

Reference: https://blog.51cto.com/zhangxueliang/2969393