MyBatis knownMappers is using class object as key of map

Hi, from the source code:

public class MapperRegistry {

  private final Configuration config;
  private final Map<Class<?>, MapperProxyFactory<?>> knownMappers = new ConcurrentHashMap<>();

  public MapperRegistry(Configuration config) {
    this.config = config;
  }

  @SuppressWarnings("unchecked")
  public <T> T getMapper(Class<T> type, SqlSession sqlSession) {
    final MapperProxyFactory<T> mapperProxyFactory = (MapperProxyFactory<T>) knownMappers.get(type);
    if (mapperProxyFactory == null) {
      throw new BindingException("Type " + type + " is not known to the MapperRegistry.");
    }
    try {
      return mapperProxyFactory.newInstance(sqlSession);
    } catch (Exception e) {
      throw new BindingException("Error getting mapper instance. Cause: " + e, e);
    }
  }

  public <T> boolean hasMapper(Class<T> type) {
    return knownMappers.containsKey(type);
  }

  public <T> void addMapper(Class<T> type) {
    if (type.isInterface()) {
      if (hasMapper(type)) {
        throw new BindingException("Type " + type + " is already known to the MapperRegistry.");
      }
      boolean loadCompleted = false;
      try {
        knownMappers.put(type, new MapperProxyFactory<>(type));
        // It's important that the type is added before the parser is run
        // otherwise the binding may automatically be attempted by the
        // mapper parser. If the type is already known, it won't try.
        MapperAnnotationBuilder parser = new MapperAnnotationBuilder(config, type);
        parser.parse();
        loadCompleted = true;
      } finally {
        if (!loadCompleted) {
          knownMappers.remove(type);
        }
      }
    }
  }

  /**
   * Gets the mappers.
   *
   * @return the mappers
   *
   * @since 3.2.2
   */
  public Collection<Class<?>> getMappers() {
    return Collections.unmodifiableCollection(knownMappers.keySet());
  }

  /**
   * Adds the mappers.
   *
   * @param packageName
   *          the package name
   * @param superType
   *          the super type
   *
   * @since 3.2.2
   */
  public void addMappers(String packageName, Class<?> superType) {
    ResolverUtil<Class<?>> resolverUtil = new ResolverUtil<>();
    resolverUtil.find(new ResolverUtil.IsA(superType), packageName);
    Set<Class<? extends Class<?>>> mapperSet = resolverUtil.getClasses();
    for (Class<?> mapperClass : mapperSet) {
      addMapper(mapperClass);
    }
  }

  /**
   * Adds the mappers.
   *
   * @param packageName
   *          the package name
   *
   * @since 3.2.2
   */
  public void addMappers(String packageName) {
    addMappers(packageName, Object.class);
  }

}

in some environment, class instance will different even the with same name, for example with spring-boot devtools restart enabled, mapper class with RestartClassloader as class loader will cause

throw new BindingException("Type " + type + " is not known to the MapperRegistry.");

can we change to use class name as key ?

Comment From: harawata

Hello @OldFarmer86 ,

It is hard to believe changing the key would fix anything. Did you test and verify the effect?

FYI, I use spring-boot-devtools along with MyBatis and everything works fine for normal usages.