Android uses Gson to generate or parse JSON

At present, the mobile phone and the server data exchange format is generally JSON, and Google provides gson to parse JSON. Download gson:https://code.google.com/p/google-gson/

The download is placed in lib and imported, if an error occurs: Java.lang.NoClassDefFoundError:com.google.gson.Gson

Because the Android-support-v4.jar is not imported, it can be imported.

One, single object generation JSON

Generate the following class, how to generate it?

{    "createdate": "2015-02-01 10:39:50",     "id": "1",     "name": "Legendary Beauty",     "password": "123456"}

First define an account class with the attributes ID, name, password, createdate.

public class Account {private string Id;private string Password;private string name;private string Createdate;public Accou NT () {super ();} Public account (string ID, string password, string name, String createdate) {super (); this.id = Id;this.password = password; THIS.name = Name;this.createdate = CreateDate;} Public String GetId () {return ID;} public void SetId (String id) {this.id = ID;} Public String GetPassword () {return password;} public void SetPassword (String password) {this.password = password;} Public String GetName () {return name;} public void SetName (String name) {this.name = name;} Public String Getcreatedate () {return createdate;} public void Setcreatedate (String createdate) {this.createdate = CreateDate;} @Overridepublic String toString () {return "account [id=" + ID + ", password=" + password + ", name=" + name + ", Createdat E= "+ createdate +"]\n\n ";}}

By defining this class, you can use Gson to generate a JSON string.

Generate Account Object SimpleDateFormat SDF = new SimpleDateFormat ("Yyyy-mm-dd hh:mm:ss"); Account Account = new Account ("1", "123456", "Legendary Beauty", Sdf.format (New Date ()));//Use Gson object to generate JSON string Gson Gson = new Gson (); String jsonstring = Gson.tojson (account);                LOG.I ("", jsonstring);

Enter the following log

second, parse the JSON string as a single object

Jsonstring has been generated above, and how to parse it into a single object is simple.

Use Gson to parse the JSON string into a single object account Account1 = Gson.fromjson (jsonstring, Account.class); LOG.I ("", account1.tostring ());

Look at the output log.

Iii. generating a JSON array of individual objects

What's the JSON array, similar to the following

[    {        "id": "2",         "CreateDate": "2015-02-01 11:21:27",         "password": "123456",         "name": "Legend"    },     {        "id": "2",         "CreateDate": "2015-02-01 11:21:27",         "password": "123456",         "name": "Beauty"    }]

Generate the JSON array code as follows

Account Account2 = new Account ("2", "123456", "Legend", Sdf.format (New Date ())); Account Account3 = new Account ("2", "123456", "Beauty", Sdf.format (New Date ())); list<account> accountlist = new arraylist<account> (); Accountlist.add (Account2); Accountlist.add ( ACCOUNT3); Jsonarray Accountarray = new Jsonarray (); for (int i = 0; i < accountlist.size (); i++) {String accountstr = Gson.tojson ( Accountlist.get (i)); Jsonobject accountobject;try {accountobject = new Jsonobject (ACCOUNTSTR); Accountarray.put (i, accountObject);} catch ( Jsonexception e) {e.printstacktrace ();}} LOG.I ("", accountarray.tostring ());

The output of log is

Four, a JSON array of multiple individual objects resolves to a single object

A JSON array consisting of multiple individual objects is parsed as follows

Parse JSON array list<account> accountList2 = new arraylist<account> (); for (int i=0;i<accountarray.length (); i++) {Jsonobject Jsonobject = null;try {jsonobject = Accountarray.getjsonobject (i);} catch (Jsonexception e) { E.printstacktrace ();} if (jsonobject! = null) {Account Tempaccount = Gson.fromjson (jsonobject.tostring (), account.class); Accountlist2.add ( Tempaccount);}} LOG.I ("AccountList2", accountlist2.tostring ());

Log of output

Or use a faster conversion method.

account[] Accountarrays = new Gson (). Fromjson (Accountarray.tostring (), account[].class); for (int i=0;i< accountarrays.length;i++) {log.i ("Accountarrays", accountarrays[i].tostring ());} Converted to listlist<account> fooslist = Arrays.aslist (accountarrays);

Resolve to list more quickly

More quickly parse into listtype ListType = new typetoken<arraylist<account>> () {}.gettype (); arraylist<account> accslist = new Gson (). Fromjson (Accountarray.tostring (), listtype); LOG.I ("Accslist", accslist.tostring ());

V. Generating JSON for an object nested object

Nested JSON is similar to the following

{"    member": {        "id": "4",         "name": "I Am Legend"    },     "id": "4",     "CreateDate": "2015-02-02 12:03:32", "     password": "888888", "     name": "Legendary Beauty"}

There are 2 ways to generate this JSON.

1. Add a member class, add it as you would add the account class.

public class Member {private string Id;private string Name;public Member () {super ();} Public Member (string ID, string name) {super (); this.id = Id;this.name = name;} Public String GetId () {return ID;} public void SetId (String id) {this.id = ID;} Public String GetName () {return name;} public void SetName (String name) {this.name = name;} @Overridepublic String toString () {return "Member [id=" + ID + ", name=" + name + "]\n\n";}}

The generated code is as follows

Generate object Nested object Jsonaccount account4 = new Account ("4", "888888", "Legendary Beauty", Sdf.format (New Date ())); Member Member = new Member ("4", "I Am Legend"); String accountstr = Gson.tojson (ACCOUNT4); String memberstr = Gson.tojson (member); Jsonobject object = null;try {jsonobject memberobject = new Jsonobject (memberstr); object = new Jsonobject (accountstr); obj Ect.put ("member", Memberobject);} catch (Jsonexception e) {e.printstacktrace ();} LOG.I ("", object.tostring ());

Log of output

Vi. parsing the JSON of object nesting objects

Account ACCOUNT5 = Gson.fromjson (Object.ToString (), account.class); LOG.I ("JSON for parsing object nesting object", account5.tostring ());//here with IsNull to determine if there is this object, the existence of member Jsonobjectjsonobject Memberobject = Null;if (!object.isnull ("member")) {try {memberobject = Object.getjsonobject ("member");} catch ( Jsonexception e) {e.printstacktrace ();}} Member MEMBER5 = null;if (null! = memberobject) {Member5 = Gson.fromjson (memberobject.tostring (), member.class); LOG.I ("JSON for parsing object nesting object", member5.tostring ());}

Results of the output

7. Another JSON for parsing object nesting objects

Define a class

public class Accountobject {private String id;private string password;private string Name;private string Createdate;priva Te memberobject memberobject = new Memberobject ();p Ublic class Memberobject {private string id;private string name; @Overri Depublic String toString () {return "Memberobject [id=" + ID + ", name=" + name+ "]\n\n";}} @Overridepublic String toString () {return "Accountobject [id=" + ID + ", password=" + password + ", name=" + name + ", CRE Atedate= "+ CreateDate +", "+ memberobject.tostring () +"]\n\n ";}}

Generate JSON and parse

try {jsonobject mobject = new Jsonobject (memberstr); object = new Jsonobject (ACCOUNTSTR); Object.put ("Memberobject", Mobject);} catch (Jsonexception e) {e.printstacktrace ();} Accountobject accountobject = Gson.fromjson (Object.ToString (), accountobject.class); LOG.I ("Accountobject", accountobject.tostring ());

Print out the log

This blog original address: http://www.cnblogs.com/liqw/p/4266209.html

Demo Download Link: http://files.cnblogs.com/files/liqw/LauncherActivity.zip

Android uses Gson to generate or parse JSON