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 annotated method or field is to be//标记方法或字段 * ignored by introspection-based//被标记的方法和字段不进行序列化和反序列化 * serialization and deserialization functionality. That is, it should * not be consider a "getter", "setter" or "creator".//实际上就是：这个注解不能被认为是一个getter,setter或creator *<p> * In addition, starting with Jackson 1.9, if this is the only annotation//1.9版本如果仅加入此注解，将会导致整个属性被忽视 * associated with a property, it will also cause the whole * property to be ignored: that is, if setter has this annotation and//如果在setter上注解，在getter上不注解，那么getter也会受影响（将不会被序列化） * getter has no annotations, getter is also effectively ignored. * It is still possible for different accessors to use different//不同的存取器可以用不同的注解 * annotations; so if only "getter" is to be ignored, other accessors//如果仅是getter加了此注解，那么其他的存取器（setter或字段） * (setter or field) would need explicit annotation to prevent//需要明确地被注解以防止不被序列化(通常使用@JsonProperty来注解） * ignoral (usually {@link JsonProperty}). * <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> * Before version 1.9, this annotation worked purely on method-by-method (or field-by-field) * basis; annotation on one method or field did not imply ignoring other methods * or fields. However, with version 1.9 and above, annotations associated * with various accessors (getter, setter, field, constructor parameter) of * a logical property are combined; meaning that annotations in one (say, setter) * can have effects on all of them (if getter or field has nothing indicating * otherwise). *<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. *<p> * Annotation is similar to {@link javax.xml.bind.annotation.XmlTransient}  */@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;}