Description
Example:
@AllArgsConstructor
@Getter
public enum GcType {
G1(1),
ZGC(2) {
@Override
public String getName() {
return "zgc";
}
},
;
public String getName() {
return this.name();
}
private int value;
}Create a custom enum TypeHandler without MappedJdbcTypes for enum GcType named CustomEnumTypeHandler.
@MappedTypes(GcType.class)
public class CustomEnumTypeHandler<E extends Enum<E>> extends BaseTypeHandler<E> {
// xxx
}now the typeHandlerRegistry.typeHandlerMap should be {xx, GcType={null=CustomEnumTypeHandler} , xx}
next step:
use
GcType.ZGCas the object param to execute db operation.
class Param {
private GcType gcType;
}
Mapper {
@Select("select xxx from xxx where xxx=#{param.gcType}")
xxx selectXXX(Param param);
}
then call it: selectXXX(new Param(GcType.ZGC))Because the GcType.ZGC's type is GcType$1, not GcType, so the typeHandlerMap can't find the typeHandler for GcType$1,
TypeHandlerRegistry#getJdbcHandlerMap
// when type = GcType$1
private Map<JdbcType, TypeHandler<?>> getJdbcHandlerMap(Type type) {
Map<JdbcType, TypeHandler<?>> jdbcHandlerMap = typeHandlerMap.get(type);
if (jdbcHandlerMap != null) {
return NULL_TYPE_HANDLER_MAP.equals(jdbcHandlerMap) ? null : jdbcHandlerMap;
}
if (type instanceof Class) {
Class<?> clazz = (Class<?>) type;
if (Enum.class.isAssignableFrom(clazz)) {
Class<?> enumClass = clazz.isAnonymousClass() ? clazz.getSuperclass() : clazz; // GcType$1.isAnonymousClass() is true, so enumClass=GcType
jdbcHandlerMap = getJdbcHandlerMapForEnumInterfaces(enumClass, enumClass);
if (jdbcHandlerMap == null) {
register(enumClass, getInstance(enumClass, defaultEnumTypeHandler)); // here will replace the previous enumClass's[jdbcType=null] typehandler
return typeHandlerMap.get(enumClass);
}
} else {
jdbcHandlerMap = getJdbcHandlerMapForSuperclass(clazz);
}
}
typeHandlerMap.put(type, jdbcHandlerMap == null ? NULL_TYPE_HANDLER_MAP : jdbcHandlerMap);
return jdbcHandlerMap;
}after the getJdbcHandlerMap method, the typeHandlerMap should be {xx, GcType={null=EnumTypeHandler} , xx}, the original {xx, GcType={null=CustomEnumTypeHandler} , xx} was replaced.
I think we' better keep it use the GcType's jdbcType TypeHandler[CustomEnumTypeHandler] if the jdbcType's TypeHandler exists , instead of replace it..
the original pr change about getJdbcHandlerMap anonymous enum #1490
MyBatis version
3.5.3