Java Stream API教程：基于属性值交集高效筛选复杂对象列表

List<Location> filteredLocations = locations.stream()
    .filter(location -> houseNumbers.contains(location.address.number))
    .collect(Collectors.toList());

// Address.java
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;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Address address = (Address) o;
        return street.equals(address.street) && number.equals(address.number);
    }

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

// Location.java
public class Location {
    private String gps; // 假设GPS是一个简单的字符串
    private Address address;

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

    public String getGps() {
        return gps;
    }

    public Address getAddress() {
        return address;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Location location = (Location) o;
        return gps.equals(location.gps) && address.equals(location.address);
    }

    @Override
    public int hashCode() {
        return java.util.Objects.hash(gps, address);
    }
}

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

public class LocationFilterExample {
    public static void main(String[] args) {
        // 模拟数据
        List<String> houseNumbersToMatch = new ArrayList<>();
        houseNumbersToMatch.add("101");
        houseNumbersToMatch.add("205");
        houseNumbersToMatch.add("303");

        List<Location> allLocations = new ArrayList<>();
        allLocations.add(new Location("GPS1", new Address("Main St", "101")));
        allLocations.add(new Location("GPS2", new Address("Oak Ave", "102")));
        allLocations.add(new Location("GPS3", new Address("Pine Ln", "205")));
        allLocations.add(new Location("GPS4", new Address("Elm Rd", "201")));
        allLocations.add(new Location("GPS5", new Address("Maple Dr", "303")));
        allLocations.add(new Location("GPS6", new Address("Willow Ct", "404")));

        // 步骤1: 将待匹配的门牌号列表转换为HashSet，以优化查找性能
        Set<String> numbersSet = new HashSet<>(houseNumbersToMatch);

        // 步骤2&3: 使用Stream API进行筛选和收集
        List<Location> filteredLocations = allLocations.stream()
            .filter(location -> numbersSet.contains(location.getAddress().getNumber()))
            .collect(Collectors.toList()); // Java 15及更早版本，或使用 .toList() for Java 16+

        // 打印结果
        System.out.println("匹配的Location对象:");
        filteredLocations.forEach(location -> 
            System.out.println("GPS: " + location.getGps() + ", Address Number: " + location.getAddress().getNumber())
        );
        /*
         * 预期输出:
         * 匹配的Location对象:
         * GPS: GPS1, Address Number: 101
         * GPS: GPS3, Address Number: 205
         * GPS: GPS5, Address Number: 303
         */
    }
}