java代码编写一个模拟物流快递系统的程序，模拟后台系统处理货物的过程。

好的，以下是一个简单的物流快递系统的 Java 代码实现，仅供参考：

import java.util.ArrayList;
import java.util.List;

public class LogisticsSystem {
    private List<Package> packages;
    private List<Warehouse> warehouses;

    public LogisticsSystem() {
        this.packages = new ArrayList<>();
        this.warehouses = new ArrayList<>();
    }

    public void createPackage(String sender, String receiver, String destination, double weight) {
        Package newPackage = new Package(sender, receiver, destination, weight);
        packages.add(newPackage);
        System.out.println("新建包裹：" + newPackage);
    }

    public void createWarehouse(String name) {
        Warehouse newWarehouse = new Warehouse(name);
        warehouses.add(newWarehouse);
        System.out.println("新建仓库：" + newWarehouse);
    }

    public void allocatePackage(Package p, Warehouse w) {
        p.setWarehouse(w);
        w.addPackage(p);
        System.out.println("将包裹 " + p + " 分配至仓库 " + w);
    }

    public void shipPackage(Package p) {
        p.setStatus(PackageStatus.SHIPPED);
        System.out.println("包裹 " + p + " 已发货");
    }

    public void receivePackage(Package p) {
        p.setStatus(PackageStatus.RECEIVED);
        System.out.println("包裹 " + p + " 已收货");
    }

    public void deliverPackage(Package p) {
        p.setStatus(PackageStatus.DELIVERED);
        System.out.println("包裹 " + p + " 已送达");
    }

    public void processPackages() {
        for (Package p : packages) {
            if (p.getStatus() == PackageStatus.CREATED) {
                // 找到离目的地最近的仓库
                Warehouse nearestWarehouse = null;
                double minDistance = Double.MAX_VALUE;
                for (Warehouse w : warehouses) {
                    double distance = calculateDistance(p.getDestination(), w.getLocation());
                    if (distance < minDistance) {
                        nearestWarehouse = w;
                        minDistance = distance;
                    }
                }

                // 分配包裹并发货
                allocatePackage(p, nearestWarehouse);
                shipPackage(p);
            } else if (p.getStatus() == PackageStatus.SHIPPED) {
                // 模拟送货过程
                System.out.println("包裹 " + p + " 正在送往目的地");
                if (Math.random() < 0.5) {
                    // 成功送达
                    deliverPackage(p);
                } else {
                    // 未能送达，重新分配仓库
                    System.out.println("包裹 " + p + " 未能送达，重新分配仓库");
                    p.getWarehouse().removePackage(p);
                    allocatePackage(p, getAvailableWarehouse());
                    shipPackage(p);
                }
            }
        }
    }

    private double calculateDistance(String location1, String location2) {
        // 省略计算距离的代码
        return Math.random() * 1000;
    }

    private Warehouse getAvailableWarehouse() {
        for (Warehouse w : warehouses) {
            if (w.getCapacity() > w.getPackageCount()) {
                return w;
            }
        }
        return null;
    }
}

class Package {
    private String sender;
    private String receiver;
    private String destination;
    private double weight;
    private PackageStatus status;
    private Warehouse warehouse;

    public Package(String sender, String receiver, String destination, double weight) {
        this.sender = sender;
        this.receiver = receiver;
        this.destination = destination;
        this.weight = weight;
        this.status = PackageStatus.CREATED;
    }

    public String getSender() {
        return sender;
    }

    public String getReceiver() {
        return receiver;
    }

    public String getDestination() {
        return destination;
    }

    public double getWeight() {
        return weight;
    }

    public PackageStatus getStatus() {
        return status;
    }

    public void setStatus(PackageStatus status) {
        this.status = status;
    }

    public Warehouse getWarehouse() {
        return warehouse;
    }

    public void setWarehouse(Warehouse warehouse) {
        this.warehouse = warehouse;
    }

    @Override
    public String toString() {
        return "Package{" +
                "sender='" + sender + '\'' +
                ", receiver='" + receiver + '\'' +
                ", destination='" + destination + '\'' +
                ", weight=" + weight +
                ", status=" + status +
                ", warehouse=" + warehouse +
                '}';
    }
}

class Warehouse {
    private String name;
    private String location;
    private int capacity;
    private List<Package> packages;

    public Warehouse(String name) {
        this.name = name;
        this.capacity = 100;
        this.packages = new ArrayList<>();
    }

    public String getName() {
        return name;
    }

    public String getLocation() {
        return location;
    }

    public void setLocation(String location) {
        this.location = location;
    }

    public int getCapacity() {
        return capacity;
    }

    public int getPackageCount() {
        return packages.size();
    }

    public void addPackage(Package p) {
        packages.add(p);
    }

    public void removePackage(Package p) {
        packages.remove(p);
    }

    @Override
    public String toString() {
        return "Warehouse{" +
                "name='" + name + '\'' +
                ", location='" + location + '\'' +
                ", capacity=" + capacity +
                ", packageCount=" + packages.size() +
                '}';
    }
}

enum PackageStatus {
    CREATED, SHIPPED, RECEIVED, DELIVERED
}

以上代码实现了一个简单的物流快递系统，包括创建包裹、创建仓库、分配包裹、发货、收货、送达等基本功能。在 `processPackages` 方法中，对于每个处于 CREATED 或 SHIPPED 状态的包裹，根据距离最近的仓库进行分配，然后发货或重新分配仓库。在模拟送货过程中，以 50% 的概率模拟成功送达或未能送达的情况。