使用Lua脚本来实现，因为Redis是单线程的，又是C语言编写的，可以使用Lua调用Redis的命令，Lua会具有排他性，所以能够保证安全。
使用Lua脚本来实现，因为Redis是单线程的，又是C语言编写的，可以使用Lua调用Redis的命令，Lua会具有排他性，所以能够保证安全。
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package com.redis.secondskill; import java.util.HashSet;import java.util.Set; import redis.clients.jedis.HostAndPort;import redis.clients.jedis.Jedis;import redis.clients.jedis.JedisPool; public class SS2 { static String luaScript ="local userid=KEYS[1];
" + "local prodid=KEYS[2];
" + "local qtkey='sec:'..prodid..":count";
" + "local usersKey='sec:'..prodid..":user";
" + "local userExists=redis.call("sismember",usersKey,userid);
" + "if tonumber(userExists)==1 then
" + " return 2;
" + "end
" + "local num = redis.call("get" ,qtkey);
" + "if tonumber(num)<=0 then
" + " return 0;
" + "else
" + " redis.call("decr",qtkey);
" + " redis.call("sadd",usersKey,userid);
" + "end
" + "return 1" ; public static boolean doSecKill(String uid,String prodid) { JedisPool jedisPool = JedisPollTool.getInstance(); Jedis jedis = jedisPool.getResource(); String sha1 = jedis.scriptLoad(luaScript); Object result= jedis.evalsha(sha1, 2, uid,prodid); String reString=String.valueOf(result); if ("0".equals( reString ) ) { System.err.println("已抢空！！"); }else if("1".equals( reString ) ) { System.out.println(uid + "抢购成功！！！！"); }else if("2".equals( reString ) ) { System.err.println("该用户已抢过！！"); }else{ System.err.println("抢购异常！！"); } JedisPollTool.distroy(jedisPool, jedis); return true; }} |
使用Lua脚本来实现，因为Redis是单线程的，又是C语言编写的，可以使用Lua调用Redis的命令，Lua会具有排他性，所以能够保证安全。
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package com.redis.secondskill; import java.util.HashSet;import java.util.Set; import redis.clients.jedis.HostAndPort;import redis.clients.jedis.Jedis;import redis.clients.jedis.JedisPool; public class SS2 { static String luaScript ="local userid=KEYS[1];
" + "local prodid=KEYS[2];
" + "local qtkey='sec:'..prodid..":count";
" + "local usersKey='sec:'..prodid..":user";
" + "local userExists=redis.call("sismember",usersKey,userid);
" + "if tonumber(userExists)==1 then
" + " return 2;
" + "end
" + "local num = redis.call("get" ,qtkey);
" + "if tonumber(num)<=0 then
" + " return 0;
" + "else
" + " redis.call("decr",qtkey);
" + " redis.call("sadd",usersKey,userid);
" + "end
" + "return 1" ; public static boolean doSecKill(String uid,String prodid) { JedisPool jedisPool = JedisPollTool.getInstance(); Jedis jedis = jedisPool.getResource(); String sha1 = jedis.scriptLoad(luaScript); Object result= jedis.evalsha(sha1, 2, uid,prodid); String reString=String.valueOf(result); if ("0".equals( reString ) ) { System.err.println("已抢空！！"); }else if("1".equals( reString ) ) { System.out.println(uid + "抢购成功！！！！"); }else if("2".equals( reString ) ) { System.err.println("该用户已抢过！！"); }else{ System.err.println("抢购异常！！"); } JedisPollTool.distroy(jedisPool, jedis); return true; }} |