MongoDB 3.2版本常用代码全整理(3) - 地理空间索引

原文地址
MongoDB的3.x版本Java驱动相对2.x做了全新的设计，类库和使用方法上有很大区别。例如用Document替换BasicDBObject、通过Builders类构建Bson替代直接输入$命令等，本文整理了基于3.2版本的常用增删改查操作的使用方法。为了避免冗长的篇幅，分为增删改、查询、聚合、地理索引等几部分。

随着移动设备的普及，基于坐标和经纬度的位置查询变得越来越流行，例如查找离当前位置最近的N辆出租车。Mongodb专门针对这种查询建立了地理空间索引:2d和2dsphere索引。2d用于平面基于坐标的位置计算，2dsphere主要用于球体，比如地球，提供了基于弧度的位置计算。

import static com.mongodb.client.model.Indexes.geo2d;  
import static com.mongodb.client.model.Indexes.geo2dsphere;  

import java.text.ParseException;  
import java.util.ArrayList;  
import java.util.Arrays;  
import java.util.List;  

import org.bson.Document;  

import com.mongodb.Block;  
import com.mongodb.MongoClient;  
import com.mongodb.client.FindIterable;  
import com.mongodb.client.MongoCollection;  
import com.mongodb.client.MongoDatabase;  
import com.mongodb.client.model.Filters;  
import com.mongodb.client.model.geojson.LineString;  
import com.mongodb.client.model.geojson.Point;  
import com.mongodb.client.model.geojson.Polygon;  
import com.mongodb.client.model.geojson.Position;  

public class GeospatialExamples {  

    public static void main(String[] args) throws ParseException {  
        MongoClient mongoClient = new MongoClient("localhost", 27017);  
        MongoDatabase database = mongoClient.getDatabase("lesson");  

        GeospatialExamples client = new GeospatialExamples(database);  
        client.show();  
        mongoClient.close();  
    }  

    private MongoDatabase database;  
    public GeospatialExamples(MongoDatabase database) {  
        this.database = database;  
    }  

    public void show() {  
        MongoCollection<Document> mc = database.getCollection("people");  
        mc.drop();  

        Document doc1 = new Document("name", "tom").append("raid", Arrays.asList(10, 10)).append("gps", new Point(new Position(10, 10)));  
        Document doc2 = new Document("name", "jone").append("raid", Arrays.asList(10.1, 10)).append("gps", new Point(new Position(10.1, 10)));  
        Document doc3 = new Document("name", "john").append("raid", Arrays.asList(10, 10.1)).append("gps", new Point(new Position(10, 10.1)));  
        Document doc4 = new Document("name", "jack").append("raid", Arrays.asList(9.9, 10)).append("gps", new Point(new Position(9.9, 10)));  
        Document doc5 = new Document("name", "mary").append("raid", Arrays.asList(10, 9.9)).append("gps", new Point(new Position(10, 9.9)));  
        Document doc6 = new Document("name", "abby").append("raid", Arrays.asList(10.2, 10)).append("gps", new Point(new Position(10.2, 10)));  
        Document doc7 = new Document("name", "adam").append("raid", Arrays.asList(10.3, 10)).append("gps", new Point(new Position(10.3, 10)));  
        Document doc8 = new Document("name", "barry").append("raid", Arrays.asList(10.4, 10)).append("gps", new Point(new Position(10.4, 10)));  
        Document doc9 = new Document("name", "anne").append("raid", Arrays.asList(10.5, 10)).append("gps", new Point(new Position(10.5, 10)));  
        mc.insertMany(Arrays.asList(doc1, doc2, doc3, doc4, doc5, doc6, doc7, doc8, doc9));  

        mc.createIndex(geo2d("raid"));  
        mc.createIndex(geo2dsphere("gps"));  

        //$geoWithin 匹配任意几何图形内搜索  
        FindIterable<Document> iterable = mc.find(Filters.geoWithin("raid", new Polygon(Arrays.asList(new Position(10.2, 10), new Position(10, 10.2), new Position(9.8, 10), new Position(10, 9.8), new Position(10.2, 10)))));  
        printResult("Filters.geoWithin raid", iterable);  

        //$geoWithinBox 在以左下角和右上角坐标构成方形内搜索  
        iterable = mc.find(Filters.geoWithinBox("raid", 9.8, 9.8, 10.2, 10.2));  
        printResult("Filters.geoWithinBox raid", iterable);  

        //$geoWithinPolygon 在多边形内搜索  
        List<Double> p1 = new ArrayList<>();  
        List<Double> p2 = new ArrayList<>();  
        List<Double> p3 = new ArrayList<>();  
        p1.add(10d);  
        p1.add(10d);  
        p2.add(10.1);  
        p2.add(10.16);  
        p3.add(10.2);  
        p3.add(10d);  
        List<List<Double>> polygon = Arrays.asList(p1, p2, p3);  
        iterable = mc.find(Filters.geoWithinPolygon("raid", polygon));  
        printResult("Filters.geoWithinPolygon raid", iterable);  

        p2.clear();  
        p2.add(9.9);  
        p2.add(10.16);  
        p3.clear();  
        p3.add(9.8);  
        p3.add(10d);  
        polygon = Arrays.asList(p1, p2, p3);  
        iterable = mc.find(Filters.geoWithinPolygon("gps", polygon));  
        printResult("Filters.geoWithinPolygon gps", iterable);  

        //$geoWithinCenter 在指定圆心和半径的圆形内搜索  
        iterable = mc.find(Filters.geoWithinCenter("raid", 10d, 10d, 0.25));  
        printResult("Filters.geoWithinCenter raid", iterable);  

        //$geoWithinCenterSphere 在球体(地球)上指定圆心和弧度搜索, 例如搜索以[10,10]为中心500米内的文档, 参数为...10d, 10d, 0.5/6371  
        iterable = mc.find(Filters.geoWithinCenterSphere("gps", 10d, 10d, 11d/6371));  
        printResult("Filters.geoWithinCenterSphere gps", iterable);  

        //$geoIntersects  
        iterable = mc.find(Filters.geoIntersects("gps", new LineString(Arrays.asList(new Position(10, 10.1), new Position(10.1, 10), new Position(10, 9.9)))));  
        printResult("Filters.geoIntersects gps", iterable);  

        //$near  
        iterable = mc.find(Filters.near("gps", new Point(new Position(10, 10)), 20566d, 0d));  
        printResult("Filters.near gps", iterable);  

        //$nearSphere  
        iterable = mc.find(Filters.nearSphere("gps", new Point(new Position(10, 10)), 20566d, 10d));  
        printResult("Filters.nearSphere gps", iterable);  
    }  

    public void printResult(String doing, FindIterable<Document> iterable) {  
        System.out.println(doing);  
        iterable.forEach(new Block<Document>() {  
            public void apply(final Document document) {  
                System.out.println(document);  
            }  
        });  
        System.out.println("------------------------------------------------------");  
        System.out.println();  
    }  
}