记录java中多字段分组

package cn.mw;

import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.Stream;

class NetworkConnection {
    private String srcIp;
    private String dstIp;
    private int srcPort;
    private int dstPort;

    public NetworkConnection() {
    }

    public NetworkConnection(String srcIp, String dstIp, int srcPort, int dstPort) {
        this.srcIp = srcIp;
        this.dstIp = dstIp;
        this.srcPort = srcPort;
        this.dstPort = dstPort;
    }

    public String getSrcIp() {
        return srcIp;
    }

    public void setSrcIp(String srcIp) {
        this.srcIp = srcIp;
    }

    public String getDstIp() {
        return dstIp;
    }

    public void setDstIp(String dstIp) {
        this.dstIp = dstIp;
    }

    public int getSrcPort() {
        return srcPort;
    }

    public void setSrcPort(int srcPort) {
        this.srcPort = srcPort;
    }

    public int getDstPort() {
        return dstPort;
    }

    public void setDstPort(int dstPort) {
        this.dstPort = dstPort;
    }

    // 省略构造函数和其他方法

    // Getter 和 Setter 方法
}

public class ConnectionGrouper {
    public static void main(String[] args) {
        // 假设你有一个 List<NetworkConnection> connections
        List<NetworkConnection> connections = Arrays.asList(
                new NetworkConnection("192.168.1.1", "192.168.2.1", 8080, 80),
                new NetworkConnection("192.168.1.2", "192.168.2.2", 8081, 81),
                new NetworkConnection("192.168.1.3", "192.168.2.3", 8081, 81),
                new NetworkConnection("192.168.1.4", "192.168.2.4", 8081, 81),
                new NetworkConnection("192.168.1.5", "192.168.2.5", 8081, 81),
                new NetworkConnection("192.168.1.6", "192.168.2.6", 8081, 81)
        );

        // 使用Java Stream API进行分组
        Map<String, List<String>> groupedConnections = connections.stream()
                .flatMap(connection -> Stream.of(
                        new AbstractMap.SimpleEntry<>("src_ip", String.valueOf(connection.getSrcIp())),
                        new AbstractMap.SimpleEntry<>("dst_ip", String.valueOf(connection.getDstIp())),
                        new AbstractMap.SimpleEntry<>("src_port", String.valueOf(connection.getSrcPort())),
                        new AbstractMap.SimpleEntry<>("dst_port", String.valueOf(connection.getDstPort()))
                ))
                .filter(entry -> !entry.getValue().equals("null"))
                .collect(Collectors.groupingBy(
                        Map.Entry::getKey,
                        Collectors.mapping(Map.Entry::getValue, Collectors.toList())
                ));

        // 输出结果
        groupedConnections.forEach((key, value) -> System.out.println(key + ": " + value));
    }
}