switch的对象不能为null

public enum WhereTypeEnum {
    eq,
    ne,
    like,
    gt,
    lt;
    public static String allValueString() {
        return Arrays.stream(WhereTypeEnum.values()).map(Enum::name)
            .collect(Collectors.joining(","));
    }
}

@Data
@Accessors(chain = true)
public class WhereRq {

    @ApiModelProperty("字段名")
    private String column;
    @ApiModelProperty("字段值，date格式化为YYYY-MM-dd hh:mm:ss")
    private Object value;
    @ApiModelProperty("条件类型")
    private WhereTypeEnum type;
}

WhereTypeEnum type = whereRq.getType();
switch (type) {
    case eq: {
        where.append("=");
        break;
    }
    case gt: {
        where.append(">");
        break;
    }