How to use JSON in Java

JSON plays a big role in data transfer, and the following is how JSON is used in Java.

Article reference: http://www.codes51.com/article/detail_99574.html

JSON string Example

[{"id": 1, "name": "Name1", "Password": "Password1", "remark": "Remark1"},{"id": 2, "name": "Name2", "Password": " Password2 "," remark ":" REMARK2 "},{" id ": 3," name ":" Name3 "," Password ":" Password3 "," remark ":" Remark3 "}]

Mainly divided into the following types:

1. Directly build the JSON string, the main code;

2. JSON strings, Java objects;

3. JSON string/json object, Java object;

4. JSON string list<?>;

5. JSON string, array of objects.

The procedure is as follows:

Testjson.java

Java Code Collection Code

Import java.util.*;

Import net.sf.json.*;

Import Com.hs.sig.ui.sgms.vo.User;

public class Testjson {

/**

* Initialize userlist size

*/

public static final int userlistsize = 3;

/**

* Build JSON strings directly

* @return

*/

Public String tojsonstring () {

Initializing the User object

User user = null;

List<user> userlist = this.inituserlist (userlistsize);

Building a JSON string

StringBuffer json = new StringBuffer ();

Json.append ("[");

for (int i = 0; i < userlist.size (); i++) {

user = Userlist.get (i);

Json.append ("{");

Json.append ("\" id\ ": \" "). Append (User.getid ()). Append (" \ ",");

Json.append ("\" name\ ": \" "). Append (User.getname ()). Append (" \ ",");

Json.append ("\" password\ ": \" "). Append (User.getpassword ()). Append (" \ ",");

Json.append ("\" Remark\ ": \" "). Append (User.getremark ()). Append ('" ');

Json.append ("},");

}

Json.deletecharat (Json.lastindexof (","));

Json.append ("]");

System.out.println ("Direct build JSON string result:" + json.tostring ());

return json.tostring ();

}

/**

* JSON strings, Java objects

* @return

*/

Public String Jsontoobject () {

StringBuffer info = new StringBuffer ();

if (This.isarray (this.tojsonstring ())) {

Jsonarray Jsonarray = Jsonarray.fromobject (this.tojsonstring ());

Jsonconfig jsonconfig = new Jsonconfig ();

Jsonconfig.setarraymode (jsonconfig.mode_list);

Jsonconfig.setrootclass (User.class);

List<user> userlist = (list<user>) Jsonserializer.tojava (Jsonarray, jsonconfig);

User user = null;

for (int i = 0; i < userlist.size (); i++) {

user = Userlist.get (i);

Info.append ("User" + (i + 1) + ". Id=" + User.getid ());

Info.append (", user" + (i + 1) + ". Name=" + user.getname ());

Info.append (", user" + (i + 1) + ". Password=" + User.getpassword ());

Info.append (", user" + (i + 1) + ". remark=" + User.getremark ());

Info.append ("\ n");

}

SYSTEM.OUT.PRINTLN ("JSON Strings, Java objects:" + info.tostring ());

}

return info.tostring ();

}

/**

* Java object, JSON string/json object

* @return

*/

Public String Objecttojson () {

Initializes a user object

User user = null;

List<user> userlist = this.inituserlist (userlistsize);

user = Userlist.get (0);

To convert the configuration of a user object

Jsonconfig jsonconfig = new Jsonconfig ();

Filter properties that do not require conversion in an object

Jsonconfig.setexcludes (new string[]{"id"});

Convert object user to JSON string

Jsonarray Jsonarray = jsonarray.fromobject (user, jsonconfig);

Jsonarray = jsonarray.fromobject (user);

Convert to JSON object

Jsonobject Jsonobject = jsonobject.fromobject (user, jsonconfig);

Jsonobject = jsonobject.fromobject (user);

return jsonarray.tostring ();

}

/**

* list<user> JSON string

* @return

*/

Public String Listtojson () {

List<user> userlist = this.inituserlist (userlistsize);

List converted to JSON string

Jsonarray Jsonarray = Jsonarray.fromobject (userlist);

System.out.println ("list<user>, JSON string:" + jsonarray.tostring ());

return jsonarray.tostring ();

}

/**

* JSON string with object array

* @return

*/

Public String Arraytojson () {

List<user> userlist = this.inituserlist (userlistsize);

user[] Userarray = new user[userlist.size ()];

for (int i = 0; i < userlist.size (); i++) {

Userarray[i] = Userlist.get (i);

}

The user array is converted to a JSON string

Jsonarray Jsonarray = Jsonarray.fromobject (Userarray);

System.out.println ("Object array, JSON string:" + jsonarray.tostring ());

return jsonarray.tostring ();

}

/**

* Initialize User

* @param the size of the Userlistsize list

* @return

*/

Private list<user> inituserlist (int userlistsize) {

User user = null;

list<user> userlist = new arraylist<user> ();

for (int i = 0; i < userlistsize; i++) {

user = new User ();

User.setid (i + 1);

User.setname ("name" + (i + 1));

User.setpassword ("Password" + (i + 1));

User.setremark ("Remark" + (i + 1));

Userlist.add (user);

}

return userlist;

}

/**

* Determine if the JSON string starts with "[", is considered jsonarray, otherwise it is identified as Jsonobject

* @param str

* @return

*/

Private Boolean IsArray (String str) {

return Str.startswith ("[")? True:false;

}

public static void Main (string[] args) {

Testjson Testjson = new Testjson ();

SYSTEM.OUT.PRINTLN ("Directly build JSON string:" + testjson.tojsonstring ());

SYSTEM.OUT.PRINTLN ("JSON Strings, Java objects:" + testjson.jsontoobject ());

System.out.println ("Java object, JSON string:" + Testjson.objecttojson ());

System.out.println ("list<user>, JSON string:" + Testjson.listtojson ());

System.out.println ("Object array, JSON string:" + Testjson.arraytojson ());

}

}

User.java


Java code

public class User {

Private Integer ID;

private String name;

private String password;

Private String remark;

Public String GetName () {

return name;

}

public void SetName (String name) {

THIS.name = name;

}

Public String GetPassword () {

return password;

}

public void SetPassword (String password) {

This.password = password;

}

Public String Getremark () {

return remark;

}

public void Setremark (String remark) {

This.remark = remark;

}

Public Integer getId () {

return ID;

}

public void SetId (Integer id) {

This.id = ID;

}

}



Directly build the JSON string: [{"id": "1", "name": "Name1", "Password": "Password1", "remark": "Remark1"},{"id": "2", "Name": "Name2", " Password ":" Password2 "," remark ":" REMARK2 "},{" id ":" 3 "," Name ":" Name3 "," Password ":" Password3 "," remark ":" Remark3 "}]

JSON strings, Java objects: USER1.ID=1,USER1.NAME=NAME1,USER1.PASSWORD=PASSWORD1,USER1.REMARK=REMARK1

User2.id=2,user2.name=name2,user2.password=password2,user2.remark=remark2

User3.id=3,user3.name=name3,user3.password=password3,user3.remark=remark3

Java object, JSON string: [{"Name": "Name1", "Password": "Password1", "remark": "Remark1"}]

List<user>. JSON string: [{"id": 1, "name": "Name1", "Password": "Password1", "remark": "Remark1"},{"id": 2, "name": " Name2 "," Password ":" Password2 "," remark ":" REMARK2 "},{" id ": 3," name ":" Name3 "," Password ":" Password3 "," remark ":" Remark3 "}]

Array of objects, JSON string: [{"id": 1, "name": "Name1", "Password": "Password1", "remark": "Remark1"},{"id": 2, "name": "Name2", " Password ":" Password2 "," remark ":" REMARK2 "},{" id ": 3," name ":" Name3 "," Password ":" Password3 "," remark ":" Remark3 "}]

How to use JSON in Java