Java简单投票系统实现教程

class Candidate {
    private String name;
    private int votes;
public Candidate(String name) {
    this.name = name;
    this.votes = 0;
}

public String getName() {
    return name;
}

public int getVotes() {
    return votes;
}

public void incrementVote() {
    this.votes++;
}

@Override
public String toString() {
    return name + ": " + votes + " 票";
}
}

import java.util.*;
public class VotingSystem {
private List candidates;
private Set hasVoted; // 记录已投票的用户ID（模拟防重复投票）
public VotingSystem() {
    this.candidates = new ArrayList<>();
    this.hasVoted = new HashSet<>();
}

// 添加候选人
public void addCandidate(String name) {
    candidates.add(new Candidate(name));
}

// 用户投票，userId用于防止重复投票
public boolean vote(String candidateName, String userId) {
    if (hasVoted.contains(userId)) {
        System.out.println("用户 " + userId + " 已投过票！");
        return false;
    }

    for (Candidate c : candidates) {
        if (c.getName().equalsIgnoreCase(candidateName)) {
            c.incrementVote();
            hasVoted.add(userId);
            System.out.println("投票成功！投给：" + candidateName);
            return true;
        }
    }

    System.out.println("候选人不存在：" + candidateName);
    return false;
}

// 显示当前投票结果
public void showResults() {
    System.out.println("\n--- 当前投票结果 ---");
    for (Candidate c : candidates) {
        System.out.println(c);
    }
}

// 获取得票最多的候选人
public Candidate getWinner() {
    Candidate winner = null;
    int maxVotes = -1;
    for (Candidate c : candidates) {
        if (c.getVotes() > maxVotes) {
            maxVotes = c.getVotes();
            winner = c;
        }
    }
    return winner;
}
}

public class Main {
    public static void main(String[] args) {
        VotingSystem vs = new VotingSystem();
    vs.addCandidate("张三");
    vs.addCandidate("李四");
    vs.addCandidate("王五");

    vs.vote("张三", "user1");
    vs.vote("李四", "user2");
    vs.vote("张三", "user3");
    vs.vote("张三", "user1"); // 重复投票，应失败

    vs.showResults();

    Candidate winner = vs.getWinner();
    if (winner != null) {
        System.out.println("获胜者是：" + winner.getName());
    }
}
}