一、实现需求
1. 登录账号以后，在首页home.html内可以点赞或者取消赞，只能点赞一次，点赞以后就不可再点赞；
取消赞以后为0.
2 点开news以后也可以点赞或者取消赞。
二.具体实现
1 util包下写一个类似DAO的组件，组件类包括Jedis初始化，获取Jedis,Jedis的获取get,set,获取集合大小等操作。
package com.nowcoder.util;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.stereotype.Service;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;
/**
* Created by Administrator on 2017/5/1.
*/
@Service
public class JedisAdapter implements InitializingBean {
private static final Logger logger = LoggerFactory.getLogger(JedisAdapter.class);
private Jedis jedis = null;
private JedisPool jedisPool = null;
@Override
public void afterPropertiesSet() throws Exception {
//初始化
jedisPool = new JedisPool("localhost", 6379);
}
//获取一个Jedis
private Jedis getJedis(){
try{
jedis = jedisPool.getResource();
}catch (Exception e){
logger.error("获取jedis失败！" + e.getMessage());
}finally {
if(jedis != null){
jedis.close();
}
}
return jedis;
}
/**
* 获取Redis中集合中某个key值
* @param key
* @return
*/
public String get(String key){
Jedis jedis = null;
try {
jedis = jedisPool.getResource();
return jedis.get(key);
}catch (Exception e){
logger.error("Jedis get发生异常 " + e.getMessage());
return null;
}finally {
if(jedis != null){
jedis.close();
}
}
}
/**
* 给Redis中Set集合中某个key值设值
* @param key
* @param value
*/
public void set(String key, String value){
Jedis jedis = null;
try {
jedis = jedisPool.getResource();
jedis.set(key, value);
}catch (Exception e){
logger.error("Jedis set 异常" + e.getMessage());
}finally {
if(jedis != null){
jedis.close();
}
}
}
/**
* 向Redis中Set集合添加值:点赞
* @return
*/
public long sadd(String key, String value){
Jedis jedis = null;
try{
jedis = jedisPool.getResource();
return jedis.sadd(key, value);
}catch (Exception e){
logger.error("Jedis sadd 异常 ：" + e.getMessage());
return 0;
}finally {
if (jedis != null){
jedis.close();
}
}
}
/**
* 移除：取消点赞
* @param key
* @param value
* @return
*/
public long srem(String key, String value){
Jedis jedis = null;
try{
jedis = jedisPool.getResource();
return jedis.srem(key, value);
}catch (Exception e){
logger.error("Jedis srem 异常：" + e.getMessage());
return 0;
}finally {
if (jedis != null){
jedis.close();
}
}
}
/**
*p判断key,value是否是集合中值
* @param key
* @param value
* @return
*/
public boolean sismember(String key, String value){
Jedis jedis = null;
try{
jedis = jedisPool.getResource();
return jedis.sismember(key, value);
}catch (Exception e){
logger.error("Jedis sismember 异常：" + e.getMessage());
return false;
}finally {
if (jedis != null){
try{
jedis.close();
}catch (Exception e){
logger.error("Jedis关闭异常" + e.getMessage());
}
}
}
}
/**
* 获取集合大小
* @param key
* @return
*/
public long scard(String key){
Jedis jedis = null;
try{
jedis = jedisPool.getResource();
return jedis.scard(key);
}catch (Exception e){
logger.error("Jedis scard 异常：" + e.getMessage());
return 0;
}finally {
if (jedis != null){
jedis.close();
}
}
}
}
2 util包下写一个util工具类，实现点赞生成键key的值。
package com.nowcoder.util;
import org.springframework.stereotype.Service;
/**
* Created by Administrator on 2017/5/1.
*/
public class RedisKeyUtil {
private static String SPLIT = ":";
private static String BIZ_LIKE = "LIKE";
private static String BIZ_DISLIKE = "DISLIKE";
/**
* 产生key:如在newsId为2上的咨询点赞后会产生key: LIKE:ENTITY_NEWS:2
* @param entityId
* @param entityType
* @return
*/
public static String getLikeKey(int entityId, int entityType){
return BIZ_LIKE + SPLIT + String.valueOf(entityType) + SPLIT + String.valueOf(entityId);
}
/**
* 取消赞:如在newsId为2上的资讯取消点赞后会产生key: DISLIKE:ENTITY_NEWS:2
* @param entityId
* @param entityType
* @return
*/
public static String getDisLikeKey(int entityId, int entityType){
return BIZ_DISLIKE + SPLIT + String.valueOf(entityType) + SPLIT + String.valueOf(entityId);
}
}
3 Service包下写上一个判断点赞还是反对的方法，当点赞后将当前点赞用户id存入likeKey集合中，同时从disLikeKey中移除此id：
package com.nowcoder.service;
import com.nowcoder.util.JedisAdapter;
import com.nowcoder.util.RedisKeyUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
/**
* Created by Administrator on 2017/5/1.
*/
@Service
public class LikeService {
@Autowired
JedisAdapter jedisAdapter;
/**
* 判断是点赞还是点反对
* @param userId
* @param entityType
* @param entityId
* @return
*/
public int getLikeStatus(int userId, int entityType, int entityId) {
//根据当前用户的userid分别生成一个likeKey 和 disLikeKey,再分别判断这两个值是否在对应的Like集合中和disLikeKey集合中
//比如如果在likeKey集合中，就返回一个1，否则返回-1
String likeKey = RedisKeyUtil.getLikeKey(entityId, entityType);
//判断值为userId 的用户是否在key为listKey 的集合中
if(jedisAdapter.sismember(likeKey, String.valueOf(userId))){
return 1;
}
String disLikeKey = RedisKeyUtil.getDisLikeKey(entityId, entityType);
return jedisAdapter.sismember(disLikeKey, String.valueOf(userId)) ? -1: 0;
}
/**
* 点赞：即当前用户点赞后，被点赞用户的like集合中就会加上一个该点赞的用户信息
* @param userId
* @param entityType
* @param entityId
* @return
*/
public long like(int userId, int entityType, int entityId){
//在当前news上点赞后获取key: LIKE:ENTITY_NEWS:2
String likeKey = RedisKeyUtil.getLikeKey(entityId, entityType);
//在喜欢集合中添加当前操作用户的userId(即当前用户点赞后，被点赞用户的like集合中就会加上一个点赞的用户信息)
jedisAdapter.sadd(likeKey, String.valueOf(userId));
String disLikeKey = RedisKeyUtil.getDisLikeKey(entityId, entityType);
jedisAdapter.srem(disLikeKey, String.valueOf(userId));
//返回点赞数量
return jedisAdapter.scard(likeKey);
}
/**
* 反对 ：即当前用户点反对后，被点反对用户的like集合中就会加上一个该点反对的用户信息
* @param userId
* @param entityType
* @param entityId
* @return
*/
public long disLike(int userId, int entityType, int entityId){
//谁点击反对，谁就出现在key为dislikeKey的Set集合中
String disLikeKey = RedisKeyUtil.getDisLikeKey(entityId, entityType);
jedisAdapter.sadd(disLikeKey, String.valueOf(userId));
//从赞中删除
String likeKey = RedisKeyUtil.getLikeKey(entityId, entityType);
jedisAdapter.srem(likeKey, String.valueOf(userId));
return jedisAdapter.scard(likeKey);
}
}
4 Controller: 调用LikeService，将当前用户id存入Redis的LikeKey集合中，并更新News表中 的like_count数量；对应的dislike也是一样。
package com.nowcoder.controller;
import com.nowcoder.model.EntityType;
import com.nowcoder.model.HostHolder;
import com.nowcoder.model.News;
import com.nowcoder.service.LikeService;
import com.nowcoder.service.NewsService;
import com.nowcoder.util.ToutiaoUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
/**
* Created by Administrator on 2017/5/1.
*/
@Controller
public class LikeController {
@Autowired
LikeService likeService;
@Autowired
NewsService newsService;
@Autowired
HostHolder hostHolder;
@RequestMapping(path = {"/like"}, method = {RequestMethod.GET, RequestMethod.POST})
@ResponseBody
public String like(@RequestParam("newsId") int newsId){
//在newsId 的资讯上加入当前用户
long likeCount = likeService.like(hostHolder.getUser().getId(), EntityType.ENTITY_NEWS, newsId);
//更新点赞数
//News news = newsService.getById(newsId);
newsService.updateLikeCount(newsId, (int)likeCount);
return ToutiaoUtil.getJSONString(0, String.valueOf(likeCount));
}
@RequestMapping(path = {"/dislike"}, method = {RequestMethod.POST, RequestMethod.GET})
@ResponseBody
public String disLike(@RequestParam("newsId") int newsId){
//点击反对：调用disLike,将当前点击反对的用户id从key为dislikeKey的集合中移除
long likeCount = likeService.disLike(hostHolder.getUser().getId(), EntityType.ENTITY_NEWS, newsId);
if(likeCount <= 0){
likeCount = 0;
}
//更新喜欢数
newsService.updateLikeCount(newsId, (int)likeCount);
return ToutiaoUtil.getJSONString(0, String.valueOf(likeCount));
}
}
5. NewsService:
public int updateLikeCount(int newsId, int likeCount){
return newsDao.updateLikeCount(newsId, likeCount);
}
NewsDao:
@Update({"update", TABLE_NAME, "set like_count=#{likeCount} where id=#{newsId}"})
int updateLikeCount(@Param("newsId") int newsId, @Param("likeCount") int likeCount);
6. 同时HomeController中首页获取News上的点赞时，要加入判断。如果是未登录，点赞数全部为0；登录后就获取点赞的状态判断是点赞还是反对。
if (localUserId != 0) {
vo.set("like", likeService.getLikeStatus(localUserId, EntityType.ENTITY_NEWS, news.getId()));
} else {
vo.set("like", 0);
}
7. NewsController中的获取News详情页也要加入这样的判断:
时间： 2025-01-05 05:42:53