SpringBoot运用Redis统计用户在线数量的两种方法实现

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>

spring.redis.host=localhost
spring.redis.port=6379

import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;

import java.util.Set;

@Service
public class OnlineUserService {

    private static final String ONLINE_USERS_KEY = "online_users";

    private final RedisTemplate<String, String> redisTemplate;

    public OnlineUserService(RedisTemplate<String, String> redisTemplate) {
        this.redisTemplate = redisTemplate;
    }

    // 用户登录
    public void login(String userId) {
        redisTemplate.opsForSet().add(ONLINE_USERS_KEY, userId);
    }

    // 用户退出
    public void logout(String userId) {
        redisTemplate.opsForSet().remove(ONLINE_USERS_KEY, userId);
    }

    // 获取在线用户数
    public Long getOnlineCount() {
        return redisTemplate.opsForSet().size(ONLINE_USERS_KEY);
    }

    // 获取所有在线用户ID
    public Set<String> getOnlineUsers() {
        return redisTemplate.opsForSet().members(ONLINE_USERS_KEY);
    }
}

import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/online")
public class OnlineUserController {

    private final OnlineUserService onlineUserService;

    public OnlineUserController(OnlineUserService onlineUserService) {
        this.onlineUserService = onlineUserService;
    }

    @PostMapping("/login/{userId}")
    public String login(@PathVariable String userId) {
        onlineUserService.login(userId);
        return userId + " 已登录";
    }

    @PostMapping("/logout/{userId}")
    public String logout(@PathVariable String userId) {
        onlineUserService.logout(userId);
        return userId + " 已退出";
    }

    @GetMapping("/count")
    public Long getCount() {
        return onlineUserService.getOnlineCount();
    }

    @GetMapping("/users")
    public Set<String> getUsers() {
        return onlineUserService.getOnlineUsers();
    }
}

import org.springframework.data.redis.connection.RedisStringCommands;
import org.springframework.data.redis.core.RedisCallback;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;

@Service
public class OnlineUserBitmapService {

    private static final String ONLINE_USERS_BITMAP_KEY = "online_users_bitmap";

    private final RedisTemplate<String, Object> redisTemplate;

    public OnlineUserBitmapService(RedisTemplate<String, Object> redisTemplate) {
        this.redisTemplate = redisTemplate;
    }

    // 用户登录（userId需为Long类型）
    public void login(Long userId) {
        redisTemplate.execute((RedisCallback<Boolean>) connection ->
                connection.setBit(ONLINE_USERS_BITMAP_KEY.getBytes(), userId, true));
    }

    // 用户退出
    public void logout(Long userId) {
        redisTemplate.execute((RedisCallback<Boolean>) connection ->
                connection.setBit(ONLINE_USERS_BITMAP_KEY.getBytes(), userId, false));
    }

    // 检查用户是否在线
    public Boolean isOnline(Long userId) {
        return redisTemplate.execute((RedisCallback<Boolean>) connection ->
                connection.getBit(ONLINE_USERS_BITMAP_KEY.getBytes(), userId));
    }

    // 获取在线用户数
    public Long getOnlineCount() {
        return redisTemplate.execute((RedisCallback<Long>) connection ->
                connection.bitCount(ONLINE_USERS_BITMAP_KEY.getBytes()));
    }

    // 统计指定范围内的在线用户数
    public Long getOnlineCount(long start, long end) {
        return redisTemplate.execute((RedisCallback<Long>) connection ->
                connection.bitCount(ONLINE_USERS_BITMAP_KEY.getBytes(), start, end));
    }
}

import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/online/bitmap")
public class OnlineUserBitmapController {

    private final OnlineUserBitmapService onlineUserBitmapService;

    public OnlineUserBitmapController(OnlineUserBitmapService onlineUserBitmapService) {
        this.onlineUserBitmapService = onlineUserBitmapService;
    }

    @PostMapping("/login/{userId}")
    public String login(@PathVariable Long userId) {
        onlineUserBitmapService.login(userId);
        return userId + " 已登录";
    }

    @PostMapping("/logout/{userId}")
    public String logout(@PathVariable Long userId) {
        onlineUserBitmapService.logout(userId);
        return userId + " 已退出";
    }

    @GetMapping("/count")
    public Long getCount() {
        return onlineUserBitmapService.getOnlineCount();
    }

    @GetMapping("/{userId}")
    public Boolean isOnline(@PathVariable Long userId) {
        return onlineUserBitmapService.isOnline(userId);
    }
}