ExtraProcessable

在fastjson-1.2.9版本后提供了ExtraProcessable接口，用于定制对象的反序列化功能。接口如下

/** * @since 1.2.9 */publicinterfaceExtraProcessable {
voidprocessExtra(Stringkey, Objectvalue);
}

如果对象没有对应public setter和public field，就会调用processExtra方法。这个可以用于一些框架实现MapBean对象的json序列化和反序列化。

例如

importjava.io.IOException;
importjava.lang.reflect.Type;
importjava.util.*;
importorg.junit.Assert;
importjunit.framework.TestCase;
importcom.alibaba.fastjson.JSON;
importcom.alibaba.fastjson.parser.deserializer.ExtraProcessable;
importcom.alibaba.fastjson.serializer.*;
publicclassBug_for_issue_265extendsTestCase {
publicvoidtest_for_issue() throwsException {
Useruser = newUser();
user.setName("wenshao");
Stringtext = JSON.toJSONString(user);
Assert.assertEquals("{\"name\":\"wenshao\"}", text);
}
publicvoidtest_for_issue_decode() throwsException {
Stringtext = "{\"name\":\"wenshao\",\"id\":1001}";
Useruser = JSON.parseObject(text, User.class);
Assert.assertEquals("wenshao", user.getName());
Assert.assertEquals(1001, user.getAttribute("id"));
}
publicstaticclassModelimplementsJSONSerializable, ExtraProcessable {
protectedMap<String, Object> attributes = newHashMap<String, Object>();
publicMap<String, Object> getAttributes() {
returnattributes;
}
publicObjectgetAttribute(Stringname) {
returnattributes.get(name);
}
@Overridepublicvoidwrite(JSONSerializerserializer, ObjectfieldName, TypefieldType,
intfeatures) throwsIOException {
serializer.write(attributes); // 定制序列化
}
@OverridepublicvoidprocessExtra(Stringkey, Objectvalue) {
attributes.put(key, value); // 定制反序列化
}
}
publicstaticclassUserextendsModel {
publicStringgetName() {
return (String) attributes.get("name");
}
publicvoidsetName(Stringname) {
attributes.put("name", name);
}
}
}