FastJson Feature

FastJson 在序列化和反序列化的過程當中提供了不少特性,好比Feature.DisableFieldSmartMatch。若是沒有選擇該Feature,那麼在反序列的過程當中，FastJson 會自動把下劃線命名的Json字符串轉化到駝峯式命名的Java對象字段中。

public enum Feature {
    /**
     * 
     */
    AutoCloseSource,
    /**
     * 
     */
    AllowComment,
    /**
     * 
     */
    AllowUnQuotedFieldNames,
    /**
     * 
     */
    AllowSingleQuotes,
    /**
     * 
     */
    InternFieldNames,
    /**
     * 
     */
    AllowISO8601DateFormat,

    /**
     * {"a":1,,,"b":2}
     */
    AllowArbitraryCommas,

    /**
     * 
     */
    UseBigDecimal,
    
    /**
     * @since 1.1.2
     */
    IgnoreNotMatch,

    /**
     * @since 1.1.3
     */
    SortFeidFastMatch,
    
    /**
     * @since 1.1.3
     */
    DisableASM,
    
    /**
     * @since 1.1.7
     */
    DisableCircularReferenceDetect,
    
    /**
     * @since 1.1.10
     */
    InitStringFieldAsEmpty,
    
    /**
     * @since 1.1.35
     * 
     */
    SupportArrayToBean,
    
    /**
     * @since 1.2.3
     * 
     */
    OrderedField,
    
    /**
     * @since 1.2.5
     * 
     */
    DisableSpecialKeyDetect,
    
    /**
     * @since 1.2.9
     */
    UseObjectArray,

    /**
     * @since 1.2.22, 1.1.54.android
     */
    SupportNonPublicField,

    /**
     * @since 1.2.29
     *
     * disable autotype key '@type'
     */
    IgnoreAutoType,

    /**
     * @since 1.2.30
     *
     * disable field smart match, improve performance in some scenarios.
     */
    DisableFieldSmartMatch,

    /**
     * @since 1.2.41, backport to 1.1.66.android
     */
    SupportAutoType,

    /**
     * @since 1.2.42
     */
    NonStringKeyAsString,

    /**
     * @since 1.2.45
     */
    CustomMapDeserializer,

    /**
     * @since 1.2.55
     */
    ErrorOnEnumNotMatch
    ;

    Feature(){
        mask = (1 << ordinal());
    }

每個Feature，都會被設置一個Mask： int mask = (1 << ordinal()); ordinal 是Feature在枚舉中的位置

設置默認的features

static {
        int features = 0;
        features |= Feature.AutoCloseSource.getMask();
        features |= Feature.InternFieldNames.getMask();
        features |= Feature.UseBigDecimal.getMask();
        features |= Feature.AllowUnQuotedFieldNames.getMask();
        features |= Feature.AllowSingleQuotes.getMask();
        features |= Feature.AllowArbitraryCommas.getMask();
        features |= Feature.SortFeidFastMatch.getMask();
        features |= Feature.IgnoreNotMatch.getMask();
        DEFAULT_PARSER_FEATURE = features;
    }

判斷feature 是否打開

return (features & feature.mask) != 0;

開啓feature

features |= feature.mask;

關閉feature

features &= ~feature.mask;

結論

單個接口要提供靈活的功能，能夠參考這種實現方式。