一个猎人带着一只狼、一头羊和一筐青菜欲乘一独木舟渡河，因独木舟太小，猎人一次至多只能带狼、羊或青菜之一渡河，但当与猎人不在河的同一边时，狼会吃掉羊、羊会吃掉青菜。试设计一个算法，帮猎人寻找一种渡河的次序让其不受损失地将狼、羊和青菜带过河去？通过贪心算法用Java语言实现问题代码

以下是使用Java语言实现猎人过河问题的代码：

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

public class HunterCrossRiverProblem {
    static final String WOLF = "wolf";
    static final String SHEEP = "sheep";
    static final String VEGETABLES = "vegetables";
    static final String HUNTER = "hunter";

    public static void main(String[] args) {
        List<String> currentSide = new ArrayList<>();
        currentSide.add(WOLF);
        currentSide.add(SHEEP);
        currentSide.add(VEGETABLES);
        currentSide.add(HUNTER);

        List<String> oppositeSide = new ArrayList<>();

        String errorMessage = crossRiver(currentSide, oppositeSide);
        if (errorMessage == null) {
            System.out.println("猎人成功将狼、羊、青菜都带到了对岸！");
        } else {
            System.out.println(errorMessage);
        }
    }

    private static String crossRiver(List<String> currentSide, List<String> oppositeSide) {
        if (isEatenByWolf(currentSide) || isEatenByWolf(oppositeSide)) {
            return "狼吃掉了羊！";
        }
        if (isEatenBySheep(currentSide) || isEatenBySheep(oppositeSide)) {
            return "羊吃掉了青菜！";
        }

        if (currentSide.size() == 1) {
            oppositeSide.add(currentSide.remove(0));
            return null;
        }

        for (String item : currentSide) {
            if (item.equals(HUNTER)) {
                continue;
            }
            List<String> newCurrentSide = new ArrayList<>(currentSide);
            newCurrentSide.remove(HUNTER);
            newCurrentSide.remove(item);

            List<String> newOppositeSide = new ArrayList<>(oppositeSide);
            newOppositeSide.add(item);

            String errorMessage = crossRiver(newCurrentSide, newOppositeSide);
            if (errorMessage == null) {
                oppositeSide.clear();
                oppositeSide.addAll(newOppositeSide);
                oppositeSide.add(HUNTER);
                return null;
            }
        }

        return "没有找到合适的渡河方案！";
    }

    private static boolean isEatenByWolf(List<String> side) {
        return (side.contains(WOLF) && side.contains(SHEEP) && !side.contains(HUNTER));
    }

    private static boolean isEatenBySheep(List<String> side) {
        return (side.contains(SHEEP) && side.contains(VEGETABLES) && !side.contains(HUNTER));
    }
}

该算法的基本思路是：每次尝试将猎人与某个物品一起带到对岸，然后在对岸判断是否安全，如果安全则完成一次渡河，否则重新回到原岸尝试其他物品。使用递归算法实现，直到找到合适的渡河方案或者没有方案为止。