（七）实体json序列化中的JsonIgnore

package com.fasterxml.jackson.annotation;import java.lang.annotation.ElementType;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;/** * Marker annotation that indicates that the logical property that * the accessor (field, getter/setter method or Creator parameter * [of {@link JsonCreator}-annotated constructor or factory method]) * is to be ignored by introspection-based * serialization and deserialization functionality. *<p> * Annotation only needs to be added to one of the accessors (often * getter method, but may be setter, field or creator parameter), * if the complete removal of the property is desired. * However: if only particular accessor is to be ignored (for example, * when ignoring one of potentially conflicting setter methods), * this can be done by annotating other not-to-be-ignored accessors * with {@link JsonProperty} (or its equivalents). This is considered * so-called "split property" case and allows definitions of * "read-only" (read from input into POJO) and "write-only" (write * in output but ignore on output) *<br> * NOTE! As Jackson 2.6, there is a new and improved way to define * `read-only` and `write-only` properties, using * {@link JsonProperty#access()} annotation: this is recommended over * use of separate <code>JsonIgnore</code> and {@link JsonProperty} * annotations. *<p> * For example, a "getter" method that would otherwise denote * a property (like, say, "getValue" to suggest property "value") * to serialize, would be ignored and no such property would * be output unless another annotation defines alternative method to use. *<p> * When ignoring the whole property, the default behavior if encountering * such property in input is to ignore it without exception; but if there * is a {@link JsonAnySetter} it will be called instead. Either way, * no exception will be thrown. *<p> * Annotation is usually used just a like a marker annotation, that * is, without explicitly defining ‘value‘ argument (which defaults * to <code>true</code>): but argument can be explicitly defined. * This can be done to override an existing `JsonIgnore` by explicitly * defining one with ‘false‘ argument: either in a sub-class, or by * using "mix-in annotations". */@Target({ElementType.ANNOTATION_TYPE, ElementType.METHOD, ElementType.CONSTRUCTOR, ElementType.FIELD})@Retention(RetentionPolicy.RUNTIME)@JacksonAnnotationpublic @interface JsonIgnore{ ???/** ????* Optional argument that defines whether this annotation is active ????* or not. The only use for value ‘false‘ if for overriding purposes ????* (which is not needed often); most likely it is needed for use ????* with "mix-in annotations" (aka "annotation overrides"). ????* For most cases, however, default value of "true" is just fine ????* and should be omitted. ????*/ ???boolean value() default true;}