Mybatis中自定义TypeHandler处理枚举详解

public interface DisplayedEnum {
 String DEFAULT_VALUE_NAME = "value";
 String DEFAULT_LABEL_NAME = "label";
 default Integer getValue() {
 Field field = ReflectionUtils.findField(this.getClass(), DEFAULT_VALUE_NAME);
 if (field == null)
  return null;
 try {
  field.setAccessible(true);
  return Integer.parseInt(field.get(this).toString());
 } catch (IllegalAccessException e) {
  throw new RuntimeException(e);
 }
 }
 @JsonValue
 default String getLabel() {
 Field field = ReflectionUtils.findField(this.getClass(), DEFAULT_LABEL_NAME);
 if (field == null)
  return null;
 try {
  field.setAccessible(true);
  return field.get(this).toString();
 } catch (IllegalAccessException e) {
  throw new RuntimeException(e);
 }
 }
 static <T extends Enum<T>> T valueOfEnum(Class<T> enumClass, Integer value) {
 if (value == null)
  throw new IllegalArgumentException("DisplayedEnum value should not be null");
 if (enumClass.isAssignableFrom(DisplayedEnum.class))
  throw new IllegalArgumentException("illegal DisplayedEnum type");
 T[] enums = enumClass.getEnumConstants();
 for (T t: enums) {
  DisplayedEnum displayedEnum = (DisplayedEnum)t;
  if (displayedEnum.getValue().equals(value))
  return (T) displayedEnum;
 }
 throw new IllegalArgumentException("cannot parse integer: " + value + " to " + enumClass.getName());
 }
}

public enum CommonsType implements DisplayedEnum {
 NORMAL("正常", 0), INVALID("无效", 1);
 String label;
 Integer value;
 private CommonsType(String label, Integer value) {
 this.label = label;
 this.value = value;
 }
}

@MappedJdbcTypes(value = JdbcType.TINYINT, includeNullJdbcType = true)
public class DefaultEnumTypeHandler extends BaseTypeHandler<DisplayedEnum> {
 private Class<DisplayedEnum> type;
 public EnumTypeHandler(){};
 public EnumTypeHandler(Class<DisplayedEnum> type) {
 if (type == null) throw new IllegalArgumentException("Type argument cannot be null");
 this.type = type;
 }
 @Override
 public void setNonNullParameter(PreparedStatement ps, int i, DisplayedEnum parameter, JdbcType jdbcType)
  throws SQLException {
 ps.setInt(i, parameter.getValue());
 }
 @Override
 public DisplayedEnum getNullableResult(ResultSet rs, String columnName) throws SQLException {
 return convert(rs.getInt(columnName));
 }
 @Override
 public DisplayedEnum getNullableResult(ResultSet rs, int columnIndex) throws SQLException {
 return convert(rs.getInt(columnIndex));
 }
 @Override
 public DisplayedEnum getNullableResult(CallableStatement cs, int columnIndex) throws SQLException {
 return convert(cs.getInt(columnIndex));
 }
 private DisplayedEnum convert(int status){
 DisplayedEnum[] objs = type.getEnumConstants();
 for(DisplayedEnum em: objs){
  if(em.getValue() == status){
  return em;
  }
 }
 return null;
 }
}

<resultMap id="xxx" type="xxx">
 ...
 <result column="type" jdbcType="TINYINT" property="type" typeHandler="xxx.xxx.xxx.DefaultEnumTypeHandler" />
 ...
</resultMap>