Jackson：项目结构分析
边浩波
目录
3、JAX-RS（Java API for RESTful Web Services）支持
作为java体系下标准的json函数库，目前默认被应用在spring boot中。jackson是一套用于Java和JVM平台的数据处理工具，包括流式json解析器/生成器函数库、数据绑定函数库（POJO和JSON的互转），以及用以处理Avro,BSON,CBOR,CSV,Smile,(Java)Properties,Protobuf,XML,和YAML编码的数据格式化模块。还有很多的数据格式模块用以支持更广泛的数据类型，诸如Guava，Joda，PCollections中的更多其他的数据类型也是支持转换的。
1、核心modules
实际的核心组件属于他们自己的项目下-包括三个核心程序包（streaming【core】，databind，annotations），数据格式（dataformat）函数库，数据类型（datatype）库，JAX-RS（提供JSON、Smile【binary JSON】、CBOR【another kind of binary JSON】、XML、YAML的自动注册）
核心modules
- Streaming(jackson-core)：定义了较低级别的流式API，并包含JSON的特定实现
- Annotations(jackson-annotations)：包含jackson的标准注解
- Databind(jackson-databind)：在Streaming包上实现了数据绑定和对象序列化，它依赖于以上两个包
2、datatype modules
支持第三方数据类型的modules
这些扩展作为jackson的module的插件（以ObjectMapper.registerModule()的方式），并通过添加序列化器和反序列化器来支持常用java库的数据类型，以便databind包（objectMapper，objectReader，objectWriter）能够对这些类型进行读写。
以下这些数据类型包是由jackson团队进行维护的：
- 标准的集合（ Collections ）数据类型modules:
- jackson-datatype-eclipse-collections: support for Eclipse Collections (NEW in Jackson 2.10!)
- jackson-datatype-guava: support for many of Guava datatypes
- jackson-datatype-hppc: support for High-Performance Primitive Containers containers
- jackson-datatype-pcollections: support for PCollections datatypes (since Jackson 2.7)
- Hibernate: support for Hibernate features (lazy-loading, proxies)
- Java 8 Modules: support or JDK 8 features and datatypes through 3 separate modules
jackson-module-parameter-names: Module that adds support for using a new JDK8 feature, ability to access names of constructor and method parameters, to allow omitting@JsonProperty.jackson-datatype-jsr310: support for "Java 8 Dates" (ones added in JDK 8)- Also, for pre-Java8 users can use one of alternate pre-Java8 backports:
jackson-datatype-jdk8: support for JDK 8 data types other than date/time types, includingOptional
- Joda datatypes:
- jackson-datatype-joda: support for types of Joda-Time date/time library datatypes
- jackson-datatype-joda-money: support types of Joda-Money datatypes (
Money,CurrencyUnit)
- jackson-datatype-jsr353: support for JSON-P ("Java JSON API") types (specifically its tree model objects)
- jackson-datatype-json-org: support for org.json library types like
JSONObject,JSONArray
此外，jackson团队并未直接维护的modules：
- jackson-datatype-bolts support for reading/writing types defined by Yandex Bolts collection types (Functional Programming inspired immutable collections)
- jackson-datatype-commons-lang3 for types of Apache Commons Lang v3
- jackson-datatype-money for "Java Money", see javax.money
- javaslang-jackson for Javaslang support (Feature-rich & self-contained functional programming in Java™ 8 and above)
- jackson-datatype-json-lib for supporting types defined by "net.sf.json" library (aka "json-lib")
- jackson-datatype-jts (JTS Geometry) for GeoJSON support
- jackson-lombok for better support of Lombok classes
- jackson-datatype-mongo for MongoDB types
- NOTE: there are a few alternatives to handling MongoDB datatypes
- jackson-module-objectify for datatypes of Objectify
- jackson-datatype-protobuf for handling datatypes defined by the standard Java protobuf library, developed by HubSpot
- NOTE! This is different from
jackson-dataformat-protobufwhich adds support for encoding/decoding protobuf content but which does NOT depend on standard Java protobuf library
- NOTE! This is different from
- TinyTypes includes Jackson module (group id
com.github.caligin.tinytypes, artifacttinytypes-jackson) - jackson-datatype-vertx for reading/writing Vert.x
org.vertx.java.core.json.JsonObjectobjects (repackagedorg.jsonnode types)
3、JAX-RS（Java API for RESTful Web Services）支持
Jackson JAX-RS Providers has handlers to add dataformat support for JAX-RS implementations (like Jersey, RESTeasy, CXF). Providers implement MessageBodyReader and MessageBodyWriter. Supported formats currently include JSON, Smile, XML, YAML and CBOR.
4、Data format modules
Data format modules 提供了除json外的其他格式支持。大部分都是简单继承了streaming的api，所以databinding组件可以使用。
- Avro: supports Avro data format, with
streamingimplementation plus additionaldatabind-level support for Avro Schemas - CBOR: supports CBOR data format (a binary JSON variant).
- CSV: supports Comma-separated values format --
streamingapi, with optional conveniencedatabindadditions - Ion (NEW with Jackson 2.9!): support for Amazon Ion binary data format (similar to CBOR, Smile, i.e. binary JSON - like)
- (Java) Properties (2.8): creating nested structure out of implied notation (dotted by default, configurable), flattening similarly on serialization
- Protobuf (2.6): supported similar to
Avro - Smile: supports Smile (binary JSON) -- 100% API/logical model compatible via
streamingAPI, no changes fordatabind - XML: supports XML; provides both
streaminganddatabindimplementations. Similar to JAXB' "code-first" mode (no support for "XML Schema first", but can use JAXB beans) - YAML: supports YAML, which being similar to JSON is fully supported with simple
streamingimplementation
另外，还有一些由其他人员开发的data format 的modules：
- BEncode: support for reading/writing BEncode (BitTorrent format) encoded data
- bson4jackson: adds support for BSON data format (by Mongo project).
- Implemented as full streaming implementation, which allows full access (streaming, data-binding, tree-model)
- Also see [MongoJack] library below; while not a dataformat module, it allows access to BSON data as well.
- EXIficient supports Efficient XML Interchange
- jackson-dataformat-msgpack adds support MessagePack (aka
MsgPack) format- Implemented as full streaming implementation, which allows full access (streaming, data-binding, tree-model)
- HOCON: experimental, partial implementation to support HOCON format -- work in progress
- Rison: Jackson backend to support Rison)
5、JVM系语言支持
类似资料：