Java Spring-Cache key配置注意事项介绍

@Cacheable(value="cacheName", key"#id")  
public ResultDTO method(int id);  

@Cacheable(value="cacheName", key"T(String).valueOf(#name).concat('-').concat(#password))  
public ResultDTO method(int name, String password);  

@Cacheable(value="cacheName", key"#user.id) 
public ResultDTO method(User user); 

@Cacheable(value="gomeo2oCache", keyGenerator = "keyGenerator") 
public ResultDTO method(User user); 

@Component 
public class CacheTestImpl implements CacheTest { 
  @Cacheable("databaseCache") 
  public Long test1() 
  { return 1L; } 
  @Cacheable("databaseCache") 
  public Long test2() 
  { return 2L; } 
  @Cacheable("databaseCache") 
  public Long test3() 
  { return 3L; } 
  @Cacheable("databaseCache") 
  public String test4() 
  { return "4"; } 
} 

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ClassCastException: java.lang.Long cannot be cast to java.lang.String 

class CacheKeyGenerator implements KeyGenerator { 
  // custom cache key 
  public static final int NO_PARAM_KEY = 0; 
  public static final int NULL_PARAM_KEY = 53; 
  @Override 
  public Object generate(Object target, Method method, Object... params) { 
    StringBuilder key = new StringBuilder(); 
    key.append(target.getClass().getSimpleName()).append(".").append(method.getName()).append(":"); 
    if (params.length == 0) { 
      return key.append(NO_PARAM_KEY).toString(); 
    } 
    for (Object param : params) { 
      if (param == null) { 
        log.warn("input null param for Spring cache, use default key={}", NULL_PARAM_KEY); 
        key.append(NULL_PARAM_KEY); 
      } else if (ClassUtils.isPrimitiveArray(param.getClass())) { 
        int length = Array.getLength(param); 
        for (int i = 0; i < length; i++) { 
          key.append(Array.get(param, i)); 
          key.append(','); 
        } 
      } else if (ClassUtils.isPrimitiveOrWrapper(param.getClass()) || param instanceof String) { 
        key.append(param); 
      } else { 
        log.warn("Using an object as a cache key may lead to unexpected results. " + 
            "Either use @Cacheable(key=..) or implement CacheKey. Method is " + target.getClass() + "#" + method.getName()); 
        key.append(param.hashCode()); 
      } 
      key.append('-'); 
    } 
    String finalKey = key.toString(); 
    long cacheKeyHash = Hashing.murmur3_128().hashString(finalKey, Charset.defaultCharset()).asLong(); 
    log.debug("using cache key={} hashCode={}", finalKey, cacheKeyHash); 
    return key.toString(); 
  } 
}