Java将GeoHash转化为对应的经纬度坐标实例代码

      2020-05-23 06:30      JAVA编程
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package com.lulei.geo;  import java.util.ArrayList; import java.util.Arrays; import java.util.HashMap; import java.util.List;  import com.lulei.geo.bean.LocationBean; import com.lulei.util.JsonUtil;  public class GeoHash {  private LocationBean location;  /**   * 1 2500km;2 630km;3 78km;4 30km   * 5 2.4km; 6 610m; 7 76m; 8 19m   */  private int hashLength = 8; //经纬度转化为geohash长度  private int latLength = 20; //纬度转化为二进制长度  private int lngLength = 20; //经度转化为二进制长度    private double minLat;//每格纬度的单位大小  private double minLng;//每个经度的单位大小  private static final char[] CHARS = {'0', '1', '2', '3', '4', '5', '6', '7',     '8', '9', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'j', 'k', 'm', 'n',     'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'};  private static HashMap<Character, Integer> CHARSMAP;    static {   CHARSMAP = new HashMap<Character, Integer>();   for (int i = 0; i < CHARS.length; i++) {    CHARSMAP.put(CHARS[i], i);   }  }    public GeoHash(double lat, double lng) {   location = new LocationBean(lat, lng);   setMinLatLng();  }    public int gethashLength() {   return hashLength;  }    /**   * @Author:lulei   * @Description: 设置经纬度的最小单位   */  private void setMinLatLng() {   minLat = LocationBean.MAXLAT - LocationBean.MINLAT;   for (int i = 0; i < latLength; i++) {    minLat /= 2.0;   }   minLng = LocationBean.MAXLNG - LocationBean.MINLNG;   for (int i = 0; i < lngLength; i++) {    minLng /= 2.0;   }  }    /**   * @return   * @Author:lulei   * @Description: 求所在坐标点及周围点组成的九个   */  public List<String> getGeoHashBase32For9() {   double leftLat = location.getLat() - minLat;   double rightLat = location.getLat() + minLat;   double upLng = location.getLng() - minLng;   double downLng = location.getLng() + minLng;   List<String> base32For9 = new ArrayList<String>();   //左侧从上到下 3个   String leftUp = getGeoHashBase32(leftLat, upLng);   if (!(leftUp == null || "".equals(leftUp))) {    base32For9.add(leftUp);   }   String leftMid = getGeoHashBase32(leftLat, location.getLng());   if (!(leftMid == null || "".equals(leftMid))) {    base32For9.add(leftMid);   }   String leftDown = getGeoHashBase32(leftLat, downLng);   if (!(leftDown == null || "".equals(leftDown))) {    base32For9.add(leftDown);   }   //中间从上到下 3个   String midUp = getGeoHashBase32(location.getLat(), upLng);   if (!(midUp == null || "".equals(midUp))) {    base32For9.add(midUp);   }   String midMid = getGeoHashBase32(location.getLat(), location.getLng());   if (!(midMid == null || "".equals(midMid))) {    base32For9.add(midMid);   }   String midDown = getGeoHashBase32(location.getLat(), downLng);   if (!(midDown == null || "".equals(midDown))) {    base32For9.add(midDown);   }   //右侧从上到下 3个   String rightUp = getGeoHashBase32(rightLat, upLng);   if (!(rightUp == null || "".equals(rightUp))) {    base32For9.add(rightUp);   }   String rightMid = getGeoHashBase32(rightLat, location.getLng());   if (!(rightMid == null || "".equals(rightMid))) {    base32For9.add(rightMid);   }   String rightDown = getGeoHashBase32(rightLat, downLng);   if (!(rightDown == null || "".equals(rightDown))) {    base32For9.add(rightDown);   }   return base32For9;  }   /**   * @param length   * @return   * @Author:lulei   * @Description: 设置经纬度转化为geohash长度   */  public boolean sethashLength(int length) {   if (length < 1) {    return false;   }   hashLength = length;   latLength = (length * 5) / 2;   if (length % 2 == 0) {    lngLength = latLength;   } else {    lngLength = latLength + 1;   }   setMinLatLng();   return true;  }    /**   * @return   * @Author:lulei   * @Description: 获取经纬度的base32字符串   */  public String getGeoHashBase32() {   return getGeoHashBase32(location.getLat(), location.getLng());  }    /**   * @param lat   * @param lng   * @return   * @Author:lulei   * @Description: 获取经纬度的base32字符串   */  private String getGeoHashBase32(double lat, double lng) {   boolean[] bools = getGeoBinary(lat, lng);   if (bools == null) {    return null;   }   StringBuffer sb = new StringBuffer();   for (int i = 0; i < bools.length; i = i + 5) {    boolean[] base32 = new boolean[5];    for (int j = 0; j < 5; j++) {     base32[j] = bools[i + j];    }    char cha = getBase32Char(base32);    if (' ' == cha) {     return null;    }    sb.append(cha);   }   return sb.toString();  }    /**   * @param base32   * @return   * @Author:lulei   * @Description: 将五位二进制转化为base32   */  private char getBase32Char(boolean[] base32) {   if (base32 == null || base32.length != 5) {    return ' ';   }   int num = 0;   for (boolean bool : base32) {    num <<= 1;    if (bool) {     num += 1;    }   }   return CHARS[num % CHARS.length];  }    /**   * @param i   * @return   * @Author:lulei   * @Description: 将数字转化为二进制字符串   */  private String getBase32BinaryString(int i) {   if (i < 0 || i > 31) {    return null;   }   String str = Integer.toBinaryString(i + 32);   return str.substring(1);  }    /**   * @param geoHash   * @return   * @Author:lulei   * @Description: 将geoHash转化为二进制字符串   */  private String getGeoHashBinaryString(String geoHash) {   if (geoHash == null || "".equals(geoHash)) {    return null;   }   StringBuffer sb = new StringBuffer();   for (int i = 0; i < geoHash.length(); i++) {    char c = geoHash.charAt(i);    if (CHARSMAP.containsKey(c)) {     String cStr = getBase32BinaryString(CHARSMAP.get(c));     if (cStr != null) {      sb.append(cStr);     }    }   }   return sb.toString();  }    /**   * @param geoHash   * @return   * @Author:lulei   * @Description: 返回geoHash 对应的坐标   */  public LocationBean getLocation(String geoHash) {   String geoHashBinaryStr = getGeoHashBinaryString(geoHash);   if (geoHashBinaryStr == null) {    return null;   }   StringBuffer lat = new StringBuffer();   StringBuffer lng = new StringBuffer();   for (int i = 0; i < geoHashBinaryStr.length(); i++) {    if (i % 2 != 0) {     lat.append(geoHashBinaryStr.charAt(i));    } else {     lng.append(geoHashBinaryStr.charAt(i));    }   }   double latValue = getGeoHashMid(lat.toString(), LocationBean.MINLAT, LocationBean.MAXLAT);   double lngValue = getGeoHashMid(lng.toString(), LocationBean.MINLNG, LocationBean.MAXLNG);   LocationBean location = new LocationBean(latValue, lngValue);   location.setGeoHash(geoHash);   return location;  }    /**   * @param binaryStr   * @param min   * @param max   * @return   * @Author:lulei   * @Description: 返回二进制对应的中间值   */  private double getGeoHashMid(String binaryStr, double min, double max) {   if (binaryStr == null || binaryStr.length() < 1) {    return (min + max) / 2.0;   }   if (binaryStr.charAt(0) == '1') {    return getGeoHashMid(binaryStr.substring(1), (min + max) / 2.0, max);   } else {    return getGeoHashMid(binaryStr.substring(1), min, (min + max) / 2.0);   }  }    /**   * @param lat   * @param lng   * @return   * @Author:lulei   * @Description: 获取坐标的geo二进制字符串   */  private boolean[] getGeoBinary(double lat, double lng) {   boolean[] latArray = getHashArray(lat, LocationBean.MINLAT, LocationBean.MAXLAT, latLength);   boolean[] lngArray = getHashArray(lng, LocationBean.MINLNG, LocationBean.MAXLNG, lngLength);   return merge(latArray, lngArray);  }    /**   * @param latArray   * @param lngArray   * @return   * @Author:lulei   * @Description: 合并经纬度二进制   */  private boolean[] merge(boolean[] latArray, boolean[] lngArray) {   if (latArray == null || lngArray == null) {    return null;   }   boolean[] result = new boolean[lngArray.length + latArray.length];   Arrays.fill(result, false);   for (int i = 0; i < lngArray.length; i++) {    result[2 * i] = lngArray[i];   }   for (int i = 0; i < latArray.length; i++) {    result[2 * i + 1] = latArray[i];   }   return result;  }    /**   * @param value   * @param min   * @param max   * @return   * @Author:lulei   * @Description: 将数字转化为geohash二进制字符串   */  private boolean[] getHashArray(double value, double min, double max, int length) {   if (value < min || value > max) {    return null;   }   if (length < 1) {    return null;   }   boolean[] result = new boolean[length];   for (int i = 0; i < length; i++) {    double mid = (min + max) / 2.0;    if (value > mid) {     result[i] = true;     min = mid;    } else {     result[i] = false;     max = mid;    }   }   return result;  }     public static void main(String[] args) {   // TODO Auto-generated method stub   GeoHash g = new GeoHash(40.221227, 116.24875);   String geoHash = g.getGeoHashBase32();   System.out.println(geoHash);   LocationBean bean = g.getLocation(geoHash);   System.out.println(JsonUtil.parseJson(bean));   System.out.println(new GeoHash(bean.getLat(), bean.getLng()).getGeoHashBase32());   System.out.println(DistanceUtil.getDistance(bean.getLat(), bean.getLng(), bean.getLat() - g.minLat, bean.getLng() - g.minLng));  }  } 

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