使用Java Stream API高效筛选复杂对象列表：基于属性值集合的交集操作

import java.util.Objects;

public class Address {
    private String street;
    private String number; // 门牌号

    public Address(String street, String number) {
        this.street = street;
        this.number = number;
    }

    public String getStreet() {
        return street;
    }

    public String getNumber() {
        return number;
    }

    // 建议重写equals和hashCode，以便在集合操作中正确比较对象
    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Address address = (Address) o;
        return Objects.equals(street, address.street) &&
               Objects.equals(number, address.number);
    }

    @Override
    public int hashCode() {
        return Objects.hash(street, number);
    }

    @Override
    public String toString() {
        return "Address{" +
               "street='" + street + '\'' +
               ", number='" + number + '\'' +
               '}';
    }
}

import java.util.Objects;

public class GPS {
    private double latitude;
    private double longitude;

    public GPS(double latitude, double longitude) {
        this.latitude = latitude;
        this.longitude = longitude;
    }

    public double getLatitude() {
        return latitude;
    }

    public double getLongitude() {
        return longitude;
    }

    @Override
    public String toString() {
        return "GPS{" +
               "latitude=" + latitude +
               ", longitude=" + longitude +
               '}';
    }
}

import java.util.Objects;

public class Location {
    private GPS gps;
    private Address address;

    public Location(GPS gps, Address address) {
        this.gps = gps;
        this.address = address;
    }

    public GPS getGps() {
        return gps;
    }

    public Address getAddress() {
        return address;
    }

    @Override
    public String toString() {
        return "Location{" +
               "gps=" + gps +
               ", address=" + address +
               '}';
    }
}

import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

// 假设这是我们感兴趣的门牌号列表
List<String> houseNumbersList = Arrays.asList("101", "205", "303", "410");

// 将List转换为HashSet，提高查找效率
Set<String> targetHouseNumbers = new HashSet<>(houseNumbersList);

System.out.println("目标门牌号集合: " + targetHouseNumbers);

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors; // JDK 15及以下版本需要

public class LocationFilterTutorial {

    public static void main(String[] args) {
        // 1. 准备数据模型 (已在上面定义)

        // 2. 准备目标门牌号集合
        List<String> houseNumbersList = Arrays.asList("101", "205", "303", "410");
        Set<String> targetHouseNumbers = new HashSet<>(houseNumbersList);

        // 3. 准备Location列表
        List<Location> locations = new ArrayList<>();
        locations.add(new Location(new GPS(34.0, -118.0), new Address("Main St", "101")));
        locations.add(new Location(new GPS(34.1, -118.1), new Address("Elm St", "102")));
        locations.add(new Location(new GPS(34.2, -118.2), new Address("Oak Ave", "205")));
        locations.add(new Location(new GPS(34.3, -118.3), new Address("Pine Ln", "300")));
        locations.add(new Location(new GPS(34.4, -118.4), new Address("Maple Dr", "410")));
        locations.add(new Location(new GPS(34.5, -118.5), new Address("Cedar Rd", "500")));
        locations.add(new Location(new GPS(34.6, -118.6), new Address("Birch Blvd", "205")));

        System.out.println("原始Location列表:");
        locations.forEach(System.out::println);
        System.out.println("--------------------");

        // 4. 使用Stream API进行过滤和收集结果
        List<Location> filteredLocations = locations.stream()
                .filter(location -> targetHouseNumbers.contains(location.getAddress().getNumber()))
                // Java 16+ 可以直接使用 .toList();
                // Java 15及以下版本使用 .collect(Collectors.toList());
                .collect(Collectors.toList()); // 或 .toList() for Java 16+

        System.out.println("过滤后的Location列表:");
        filteredLocations.forEach(System.out::println);
    }
}