使用spring拦截器做频率限制

àì夳堔傛蜴生んèń 2021-09-14 15:38 395阅读 0赞

1. 注解类 Frequency

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1.  @Target (\{ElementType.TYPE, ElementType.METHOD\})      
2.  @Retention (RetentionPolicy.RUNTIME)      
3.  @Documented       
4.  @Component      
5.  public @interface Frequency \{  
6.    
7.      String name() default "all";  
8.      int time()  default 0;  
9.      int limit()  default 0;  
10. \}

2. 拦截对象封装 FrequencyStruct

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1.  public class FrequencyStruct \{  
2.    
3.      String uniqueKey;  
4.      long start;  
5.      long end;  
6.      int time;  
7.      int limit;  
8.      List<Long> accessPoints = new ArrayList<Long>();  
9.        
10.     public void reset(long timeMillis) \{  
11.           
12.         start = end = timeMillis;  
13.         accessPoints.clear();  
14.         accessPoints.add(timeMillis);  
15.     \}  
16.   
17.     @Override  
18.     public String toString() \{  
19.         return "FrequencyStruct \[uniqueKey=" + uniqueKey + ", start=" + start  
20.                 + ", end=" + end + ", time=" + time + ", limit=" + limit  
21.                 + ", accessPoints=" + accessPoints + "\]";  
22.     \}  
23. \}

3. FrequencyHandlerInterceptor会拦截所有带Frequency注解的类或方法

如果是有负载情况下，会取x-forwarded-for头里的ip地址，经过负载的请求必须带x-forwarded-for头，记录用户ip。

频率限制使用本地内存做数据基站，初始化时会开辟MAX\_BASE\_STATION\_SIZE长度的HashMap，MAX\_BASE\_STATION\_SIZE得默认值是100000。

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1.  public class FrequencyHandlerInterceptor extends HandlerInterceptorAdapter \{  
2.        
3.      private Logger logger = LoggerFactory.getLogger(FrequencyHandlerInterceptor.class);   
4.      private static final int MAX\_BASE\_STATION\_SIZE = 100000;  
5.      private static Map<String, FrequencyStruct> BASE\_STATION = new HashMap<String, FrequencyStruct>(MAX\_BASE\_STATION\_SIZE);  
6.      private static final float SCALE = 0.75F;  
7.      private static final int MAX\_CLEANUP\_COUNT = 3;  
8.      private static final int CLEANUP\_INTERVAL = 1000;  
9.      private Object syncRoot = new Object();  
10.     private int cleanupCount = 0;  
11.       
12.     @Override  
13.     public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception \{  
14.           
15.         Frequency methodFrequency = ((HandlerMethod) handler).getMethodAnnotation(Frequency.class);  
16.         Frequency classFrequency = ((HandlerMethod) handler).getBean().getClass().getAnnotation(Frequency.class);  
17.           
18.         boolean going = true;  
19.         if(classFrequency != null) \{  
20.             going = handleFrequency(request, response, classFrequency);  
21.         \}  
22.           
23.         if(going && methodFrequency != null) \{  
24.             going = handleFrequency(request, response, methodFrequency);  
25.         \}  
26.         return going;  
27.     \}  
28.   
29.     private boolean handleFrequency(HttpServletRequest request, HttpServletResponse response, Frequency frequency) \{  
30.           
31.         boolean going = true;  
32.         if(frequency == null) \{  
33.             return going;  
34.         \}  
35.           
36.         String name = frequency.name();  
37.         int limit = frequency.limit();  
38.         int time = frequency.time();  
39.           
40.         if(time == 0 || limit == 0) \{  
41.             going = false;  
42.             response.setStatus(HttpServletResponse.SC\_FORBIDDEN);  
43.             return going;  
44.         \}  
45.               
46.         long currentTimeMilles = System.currentTimeMillis() / 1000;  
47.           
48.         String ip = getRemoteIp(request);  
49.         String key = ip + "\_" + name;  
50.         FrequencyStruct frequencyStruct = BASE\_STATION.get(key);  
51.           
52.         if(frequencyStruct == null) \{  
53.               
54.             frequencyStruct = new FrequencyStruct();  
55.             frequencyStruct.uniqueKey = name;  
56.             frequencyStruct.start = frequencyStruct.end = currentTimeMilles;  
57.             frequencyStruct.limit = limit;  
58.             frequencyStruct.time = time;  
59.             frequencyStruct.accessPoints.add(currentTimeMilles);  
60.   
61.             synchronized (syncRoot) \{  
62.                 BASE\_STATION.put(key, frequencyStruct);  
63.             \}  
64.             if(BASE\_STATION.size() > MAX\_BASE\_STATION\_SIZE \* SCALE) \{  
65.                 cleanup(currentTimeMilles);  
66.             \}  
67.         \} else \{  
68.               
69.             frequencyStruct.end = currentTimeMilles;  
70.             frequencyStruct.accessPoints.add(currentTimeMilles);  
71.         \}  
72.           
73.         //时间是否有效  
74.         if(frequencyStruct.end - frequencyStruct.start >= time) \{  
75.               
76.             if(logger.isDebugEnabled()) \{  
77.                 logger.debug("frequency struct be out of date, struct will be reset., struct: \{\}", frequencyStruct.toString());  
78.             \}  
79.             frequencyStruct.reset(currentTimeMilles);  
80.         \} else \{  
81.               
82.             int count = frequencyStruct.accessPoints.size();  
83.             if(count > limit) \{  
84.                 if(logger.isDebugEnabled()) \{  
85.                     logger.debug("key: \{\} too frequency. count: \{\}, limit: \{\}.", key, count, limit);  
86.                 \}  
87.                 going = false;  
88.                 response.setStatus(HttpServletResponse.SC\_FORBIDDEN);  
89.             \}  
90.         \}  
91.         return going;  
92.     \}  
93.   
94.     private void cleanup(long currentTimeMilles) \{  
95.           
96.         synchronized (syncRoot) \{  
97.               
98.             Iterator<String> it = BASE\_STATION.keySet().iterator();  
99.             while(it.hasNext()) \{  
100.                   
101.                 String key = it.next();  
102.                 FrequencyStruct struct = BASE\_STATION.get(key);  
103.                 if((currentTimeMilles - struct.end) > struct.time) \{  
104.                     it.remove();  
105.                 \}  
106.             \}  
107.               
108.             if((MAX\_BASE\_STATION\_SIZE - BASE\_STATION.size()) > CLEANUP\_INTERVAL) \{  
109.                 cleanupCount = 0;  
110.             \} else \{  
111.                 cleanupCount++;  
112.             \}  
113.               
114.             if(cleanupCount > MAX\_CLEANUP\_COUNT ) \{  
115.                 randomCleanup(MAX\_CLEANUP\_COUNT);  
116.             \}  
117.         \}  
118.     \}  
119.   
120.     /\*\* 
121.      \* 随机淘汰count个key 
122.      \*  
123.      \* @param maxCleanupCount 
124.      \*/  
125.     private void randomCleanup(int count) \{  
126.         //防止调用错误  
127.         if(BASE\_STATION.size() < MAX\_BASE\_STATION\_SIZE \* SCALE) \{  
128.             return;  
129.         \}  
130.           
131.         Iterator<String> it = BASE\_STATION.keySet().iterator();  
132.         Random random = new Random();  
133.         int tempCount = 0;  
134.           
135.         while(it.hasNext()) \{  
136.             if(random.nextBoolean()) \{  
137.                 it.remove();  
138.                 tempCount++;  
139.                 if(tempCount >= count) \{  
140.                     break;  
141.                 \}  
142.             \}  
143.         \}  
144.     \}  
145.       
146.     private String getRemoteIp(HttpServletRequest request) \{  
147.   
148.         String ip = request.getHeader("x-forwarded-for");  
149.         if(StringUtils.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) \{  
150.             ip = request.getHeader("Proxy-Client-IP");  
151.         \}  
152.   
153.         if(StringUtils.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) \{  
154.             ip = request.getHeader("WL-Proxy-Client-IP");  
155.         \}  
156.   
157.         if(StringUtils.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) \{  
158.             ip = request.getRemoteAddr();  
159.         \}  
160.   
161.         return ip;  
162.   
163.     \}  
164. \}

4. 配置使用

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1.    
2.      <mvc:interceptors>    
3.             
4.          <bean class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor" />    
5.            
6.          <bean class="xxx.annotation.FrequencyHandlerInterceptor"></bean>  
7.      </mvc:interceptors>

5. 可以使用在Controller或单独某个方法上。最好给每个name都定义单独的name，默认all的范围太广，使用方法如下：

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1.  @Controller  
2.  @RequestMapping("/demo")  
3.  @Frequency(name="demo", limit=3, time=1)  
4.  public class DemoController \{  
5.    
6.      @RequestMapping(value = \{ "index"\})  
7.    
8.       @Frequency(name="method", limit=3, time=1)  
9.    
10.      public void method()  
11.   
12. \}  
13.

[view plain]: http://blog.csdn.net/nrs12345/article/details/50459521#