JSON parsing tool Jackson (simple Application)

Overview
Jackson Library (http://jackson.codehaus.org), a java-based open source JSON format parsing tool, contains 3 jar packages for the entire library (using the latest version 2.2):
the Jackson-core.jar--core Package (required) provides an API based on "stream mode" parsing.
the Jackson-databind--data Binding Package (optional) provides APIs based on the object binding and tree Model.
The Jackson-annotations--annotation package (optional) provides annotation Functionality.
Jackson's Advantages
compared to other libraries parsed by Java json, such as the json-lib, Gson package, Jackson has the following advantages:
1. Comprehensive function, provide a variety of modes of JSON parsing, "object binding" easy to use, the use of annotations package can provide a lot of convenience for our Development.
2. High performance, "flow mode" parsing efficiency more than most similar JSON package.
Important API
Core package: Jsonpaser (json stream read), jsongenerator (json stream output).
Data binding package: Objectmapper (build tree Mode and object binding mode), Jsonnode (tree node).
Simple Example
in practice, most of the data object binding patterns are used, an object is serialized as a JSON string, and a string of JSON strings are deserialized into a Java object or map.

Person Class:

 public classperson {PrivateString name; PrivateInteger age; //necessary for     publicperson () {} publicperson (String name, Integer age) { this. Name =name;  this. Age =age ; }     publicString getName () {returnname; }     public voidsetName (String Name) { this. Name =name; }     publicInteger getage () {returnage ; }     public voidsetage (Integer Age) { this. Age =age ; }}

Test class

/*** The example itself is simple, but the writing in the main method is well worth learning from the idea of refactoring*/ public classDemo { public Static voidmain (string[] Args) {//Writejsonobject (); //Readjsonobject ();Readjsonmap (); }    //write directly to an object (serialized)     public Static voidwritejsonobject () {objectmapper mapper=NewObjectmapper (); person Person=NewPerson ("nomouse", 25); Try{mapper.writevalue (NewFile ("c:/person.json"), person); String String=mapper.writevalueasstring (person);        System.out.println (string); } Catch(jsongenerationexception E) {e.printstacktrace (); } Catch(jsonmappingexception E) {e.printstacktrace (); } Catch(ioexception E) {e.printstacktrace (); }    }    //converts a JSON directly into an object (deserialization)     public Static voidreadjsonobject () {objectmapper mapper=NewObjectmapper (); Try{ person person= Mapper.readvalue (NewFile ("c:/person.json"), Person.class); System.out.println (person.getname ()+ ":" +Person.getage ()); String String= "{\" name\ ": \" nomouse\ ", \" age\ ": 25}"; //person must have an Argument-free construction methodPerson Person1 = Mapper.readvalue (string, Person.class); System.out.println (person1.getname ()+ ":" +Person1.getage ()); } Catch(jsonparseexception E) {e.printstacktrace (); } Catch(jsonmappingexception E) {e.printstacktrace (); } Catch(ioexception E) {e.printstacktrace (); }    }    //Direct conversion to map     public Static voidreadjsonmap () {objectmapper mapper=NewObjectmapper (); Try {            //it is important to note that the map here is actually a likedhashmap, a chain hash table, which can be traversed in the read-in order .Map map = Mapper.readvalue (NewFile ("c:/person.json"), Map.class); System.out.println (map.get ("name") + ":" + map.get ("age")); String String= "{\" name\ ": \" nomouse\ ", \" age\ ": 25}"; //person must have an Argument-free construction methodMap Map1 = Mapper.readvalue (string, Map.class);        System.out.println (map1); } Catch(jsonparseexception E) {e.printstacktrace (); } Catch(jsonmappingexception E) {e.printstacktrace (); } Catch(ioexception E) {e.printstacktrace (); }    }}

JSON parsing tool Jackson (simple Application)