【技术累积】【点】【java】【27】@JSONField

@JSONField

该注解隶属于阿里fastjson，方便fastjson处理对象时的一些操作

源码

@Retention(RetentionPolicy.RUNTIME)
@Target({ ElementType.METHOD, ElementType.FIELD, ElementType.PARAMETER })
public @interface JSONField {/*** config encode/decode ordinal* @since 1.1.42* @return*/int ordinal() default 0;String name() default "";String format() default "";boolean serialize() default true;boolean deserialize() default true;SerializerFeature[] serialzeFeatures() default {};Feature[] parseFeatures() default {};String label() default "";/*** @since 1.2.12*/boolean jsonDirect() default false;/*** Serializer class to use for serializing associated value.* * @since 1.2.16*/Class<?> serializeUsing() default Void.class;/*** Deserializer class to use for deserializing associated value. * * @since 1.2.16 */Class<?> deserializeUsing() default Void.class;/*** @since 1.2.21* @return the alternative names of the field when it is deserialized*/String[] alternateNames() default {};/*** @since 1.2.31*/boolean unwrapped() default false;
}

ordinal() 顺序设置。

缺省fastjson序列化一个java bean，是根据fieldName的字母序进行序列化的，你可以通过ordinal指定字段的顺序。这个特性需要1.1.42以上版本
name() 指定名字。指定后，序列化后字段名变为指定名称，反序列化同理；
format() 指定日期格式；
serialize() deserialize() 是否序列化和反序列化，默认true。
serialzeFeatures() 序列化特性选择，具体参考后面文章吧；通过枚举选择
parseFeatures() 解释特性选择；通过枚举选择
label() 打标记，可定制化输出

@JSONField(label = "normal")public int getId() {return id;}public void setId(int id) {this.id = id;}@JSONField(label = "normal")public String getName() {return name;}
System.out.println(JSON.toJSONString(v, Labels.includes("normal")));

jsonDirect() 直接输出而不经过json转译

在fastjson-1.2.12版本中，JSONField支持一个新的配置项jsonDirect，它的用途是：当你有一个字段是字符串类型，里面是json格式数据，你希望直接输入，而不是经过转义之后再输出。
serializeUsing() deserializeUsing() 指定序列化、反序列化使用自定义Serialize、Parser（注意，直接写在类中即可，格式固定，关键是取值）

//示例1
public static class TimeStampDeserializer implements ObjectDeserializer {@Overridepublic <T> T deserialze(DefaultJSONParser parser, Type type, Object fieldName) {String time = parser.getLexer().stringVal();if (StringUtils.isBlank(time)) {return (T)String.valueOf(new Date().getTime());} else {return (T)(time + "000");}}@Overridepublic int getFastMatchToken() {return 0;}}//示例2
public static class Model {@JSONField(serializeUsing = ModelValueSerializer.class)public int value;
}public static class ModelValueSerializer implements ObjectSerializer {@Overridepublic void write(JSONSerializer serializer, Object object, Object fieldName, Type fieldType,int features) throws IOException {Integer value = (Integer) object;String text = value + "元";serializer.write(text);}
}

alternateNames() 多名字。允许多个名字的变量转成一个

@JSONField(alternateNames = {"user", "person"})
public String name;

unwrapped() 不封箱

搭配JSON.parseObject

给输出结构体中field配置上@JSONField(name="aaa")等，直接转出得到的json串

Response response = JSON.parseObject(res, Response.class);@Setter
@Getter
@NoArgsConstructor
@ToString
public class Response {@JSONField(name = "answerList")private List<Answer> answers;@JSONField(name = "timeStamp")private String timeStamp;@JSONField(name = "type")private String answerType;@JSONField(name = "id")private String erp;@JSONField(name = "session")private String sessionId;@JSONField(name = "topic")private String topic;@JSONField(deserialize = false, serialize = false)private String answerType = AnswerTypeEnum.ANSWER.getCode();
}