Use in the Json--java

1. Building the JSON method (data-->json)

Use MAVEN to build your project here

Add the following dependencies in the Pom.xml

 <Dependency>      <groupId>Org.json</groupId>      <Artifactid>Json</Artifactid>      <version>20090211</version>    </Dependency>

1.1 Create Jsonobject object, use put (Key,value) assignment, toString () print out JSON format

Keywords: jsonobject object, put (), toString ()

 Public classJsonobjectsimple { Public Static voidMain (string[] args) {jsonobjectsimple (); }        Private Static voidjsonobjectsimple () {jsonobject Xiaofeng=NewJsonobject (); Object Nullobj=NULL;//because of the put () method, NULL is not directly used here, so null objects are created to skip the compiler's check        Try{xiaofeng.put ("Name", "Xiao Feng"); Xiaofeng.put ("Age", 22); Xiaofeng.put ("Birthday", "1999-11-22"); Xiaofeng.put ("School", "Qinghua University"); Xiaofeng.put ("Major",NewString[] {"Sing", "coding"}); Xiaofeng.put ("Girlfriend", "true"); Xiaofeng.put ("Car", nullobj);//You cannot use NULL directly, you need to create a null object to skip the compiler's checkXiaofeng.put ("comment", "JSON cannot use annotations directly, you need to add this way: "); } Catch(jsonexception e) {//TODO auto-generated Catch blockE.printstacktrace ();         } System.out.println (Xiaofeng.tostring ()); }   }

Copy the console output to http://www.jsoneditoronline.org/to view the JSON data structure

1.2 Build with HashMap

Key words: HashMap (), put (), toString (), Jsonobject (Xiaofeng)

Private Static voidCreatejsonbymap () {Map<String,Object> xiaofeng=NewHashmap<string,object>(); Object Nullobj=NULL; Xiaofeng.put ("Name", "Xiao Feng"); Xiaofeng.put ("Age", 22); Xiaofeng.put ("Birthday", "1999-11-22"); Xiaofeng.put ("School", "Qinghua University"); Xiaofeng.put ("Major",NewString[] {"Sing", "coding"}); Xiaofeng.put ("Girlfriend", "true"); Xiaofeng.put ("Car", nullobj);//You cannot use NULL directly, you need to create a null object to skip the compiler's checkXiaofeng.put ("comment", "JSON cannot use annotations directly, you need to add this way: "); System.out.println (NewJsonobject (Xiaofeng). toString ()); }

3. Create JSON using JavaBean

Key words: JavaBean, setxxx (), Jsonobject (Xiaofeng)

First create the JavaBean class person (slightly), and then create ...

 private  static  void   Createjsonbybean () { // Span style= "color: #008000;" > Create the person object, assign a value with the set () method, and finally turn to the Jsonobject object output  person xiaofeng=new   person ();        Xiaofeng.setname ( "Xiao Feng" );        Xiaofeng.setage ( 22.5);        Xiaofeng.setgirlfriend ( true  ); Xiaofeng.setmajor ( new  string[]{"Sing", "coding"                }); System.out.println ( new   Jsonobject (                Xiaofeng)); }

Note that when you create JavaBean, because JSON does not support date format, the date format needs to be set to string type, which is also a drawback of JSON.

2. Parsing read JSON data (json--> data)

Xiaofeng.json

{  "birthday": "1999-11-22",  "Girlfriend": "true",  "Major": [     "Sing",    "coding"  ],  "school": "Qinghua University",  null  ,  "name": "Xiao Feng",  "comment": "JSON cannot use annotations directly, you need to add this way." ",  " age ":

Reading JSON from a file

Keywords:

ReadJSON.class.getResource ("/xiaofeng.json"). GetFile (), jsonarray,readfiletostring (file)

Public class Readjson {public staticvoidMain (string[] args) throws IOException, jsonexception {//get the JSON file under this file pathFile file=NewFile (ReadJSON.class.getResource ("/xiaofeng.json"). GetFile ()); //read JSON file contentsString content=fileutils.readfiletostring (file); Jsonobject Jsonobject=Newjsonobject (content);
System.out.println ("Name is:" +jsonobject.getstring ("name")); System.out.println ("Age is:" +jsonobject.getdouble ("ages"))); System.out.println ("Do you have a girlfriend?" +jsonobject.getboolean ("Girlfriend"));
        //array type is converted to Jsonarray type to parse and cannot be read directly Jsonarray Majorarray=jsonobject.getjsonarray ("Major");  for(intI=0;i<majorarray.length (); i++) {String m=(String) majorarray.get (i); System.out.println ("Professional--" + (i+1) +m); }    }    }

Console output

　　　　　　　　　　　　　　

To increase the robustness of the program, you can add non-null "isNull ()" judgment when JSON data is parsed

// determine if name is empty        if (!jsonobject.isnull ("name")) {            System.out.println ("name is:" + jsonobject.getstring ("name"));        }         // Counter example, no output        if (!jsonobject.isnull ("NME")) {            System.out.println ("name is:" + jsonobject.getstring ("name"));        }        System.out.println ("Age is:" + jsonobject.getdouble ("ages"));

Use in the Json--java