Android App--the use of Google's official JSON parsing tool Gson

I. Introduction of Gson

Gson(also known asGoogleGson) isGoogleThe company released an open source codeJavalibrary, mainly used forSerialization of Javaobject isJsonstring, or anti-Serialization JSONstring intoJavaobject. That is, the Java object and the JSON string between the conversion, parsing.

Ii. Methods of Use

Gson's application is mainly for the Tojson and Fromjson two conversion functions, and before using this kind of object conversion, you need to first create the type of the object and its members to successfully the JSON string is successfully converted into the corresponding object. That is, to create a corresponding javabean,javabean in the field and the JSON to be converted to each corresponding, or there will be a failure to resolve the situation.

Parse JSON into a JavaBean object:

JavaBean

public class Person {private string name;private int age;private string Gender;public string GetName () {return name;} public void SetName (String name) {this.name = name;} public int getage () {return age;} public void Setage (int.) {this.age = age;} Public String Getgender () {return gender;} public void Setgender (String gender) {This.gender = Gender;<pre name= "code" class= "Java" >

}}

JSON string:

{"Name": "Zhangsan", "age": +, "gender": "Male"}

Parse this JSON string into a Java object:

Person person = new Gson (). Fromjson (JSON, person.class);

This allows you to parse the JSON string into a JavaBean object.
Insert a bit, the JSON string and the conversion between the Jsonobject objects, because some places may need JSON strings, some places need to be jsonobject objects
The JSON string is converted intoJsonobjectObject:

Jsonobject jsonobject = new Jsonobject (JSON);

Jsonobject object to JSON string

String jsonstring = json.tostring ();

The above situation is only one of the simplest examples, if the JSON string is slightly more complex, it involves the nesting of objects to see the following example:

{    "Status_code": "0",    "result": {        "card_edate": "1451491200",        "Edate_remark": "Get free before December 31, 2015", "        Card_remark": "1, members enjoy a variety of value-added privileges \r\n2, member exclusive pre-save 500",        "merchant_id": "2",        "card_img": "/http Www.yuelife.com/srdz_pic/baralogo.jpg ",        " card_id ":" 2 "    },    " Status_desc ":" OK "}

This is a JSON string returned by the server, where the object is nested, and the result parameter inside the JSON string is also an object. This situation is handled in the following way:

Jsonobject jsonobject = json.optjsonobject ("result");

In this way, a Jsonobject object is obtained and then the object can be JavaBean or parsed directly by this Jsonobject object. If you want to get JavaBean object, directly with the Fromjson can, if you want to parse the result of a parameter, then do the following:

String Cardnumber = jsonobject.optstring ("card_id");

This will give you a Cardnumber value.
The above case is the nesting of objects, there is also a case of nesting of arrays, see the following example:

{"Status_code": "0", "result": [{"Rows": [{"Branch_longitud E ":" 113.9760310000 "," Branch_userid ":" 273 "," branch_addr ":" Yi Tian Holiday Plaza, no. No. 9028 Shennan Avenue, Nanshan District, Shenzhen L 3 layers "," branch_status ":" 1 "," Is_default ":" 1 "," Branch_phone ":" 13 316467909,18875900656 "," Branch_creattime ":" 0 "," City ":" Shenzhen ","                    Branch_park ":" In front of the parking space "," province ":" Guangdong "," Branch_guidelines ":" 11 Road Bus ",                    "Branch_updatetime": "0", "merchant_id": "2", "Branch_precision": "", "Branch_latitude": "22.5375870000", "branch_id": "" "," Branch_name ":"                Cosmopolitan Panyu Store "}]," shop_city ":" Shenzhen "}, {" Rows ": [                    {"Branch_longitude": "113.3802380000", "Branch_userid": "273", "branch_addr": "Guangzhou city, Guangdong Province"                    Fanyu District nan Cun zhen Panyu Avenue (formerly Yingbin Road) A2 Building, 1-2 Floor "," Branch_status ":" 1 "," Is_default ":" 0 ", "Branch_phone": "13711112346,02038823585", "Branch_creattime": "0", "City": "Guang State City "," Branch_park ":" in front of parking space "," province ":" Guangdong "," Branch_guideline S ":" 120-way Bus "," branch_updatetime ":" 0 "," merchant_id ":" 2 "," Bra                    Nch_precision ":", "Branch_latitude": "23.0032640000", "branch_id": "26", "Branch_name": "Cosmopolitan Fanyu District nan Cun zhen Panyu Store"}], "shop_city": "Guangzhou"}], "s Tatus_desc ":" OK "}

Above is the JSON object returned by the server, which is a little bit more complex, involving nesting of objects and arrays. The value of the result field is an array with objects and arrays nested inside the array. In this case, the solution is actually very simple, that is, [] the contents of the [] as a collection to handle, the contents of {} as objects to handle
So this JSON parsing, first look at the result of the [] content, is composed of two {} is the object, therefore, the following paragraph is defined as a javabean, and then resolved to the object

{"Rows": [                    {"Branch_longitude": "113.9760310000", "Branch_userid": "273", "Branch_addr": "L3, Yi Tian Holiday Plaza, no. No. 9028 Shennan Avenue, Nanshan District, Shenzhen", "Branch_status": "1", "Is_                    Default ":" 1 "," Branch_phone ":" 13316467909,18875900656 "," Branch_creattime ":" 0 ",                    "City": "Shenzhen", "Branch_park": "Parking spaces in front of the door", "Province": "Guangdong", "Branch_guidelines": "11 Road Bus", "branch_updatetime": "0", "merchant_id": " 2 "," Branch_precision ":" "," Branch_latitude ":" 22.5375870000 ","         branch_id ":", "Branch_name": "Cosmopolitan Panyu Shop"}], "shop_city": "Shenzhen" }

The JavaBean defined are as follows:

public class Orderseatrows {private list<orderstorebean> rows;private String shop_city;public list< Orderstorebean> getRows () {return Rows;} public void Setrows (list<orderstorebean> rows) {rows = rows;} Public String getshop_city () {return shop_city;} public void setshop_city (String shop_city) {this.shop_city = shop_city;}}

Because the Rows field in the JavaBean is also made up of [], that is, rows is also an array, so the rows are treated as a collection, and the contents of {} are defined as a JavaBean, parsed into objects

public class Orderstorebean {private string Branch_addr;private string Branch_userid;private string branch_id;private String Branch_name;private string Province;private string city;private string Branch_status;private string Branch_ Latitude;private string Branch_longitude;private string is_default;private string Branch_phone;private string Branch_ Creattime;private string Branch_park;private string Branch_guidelines;private string Branch_updatetime;private string Merchant_id;private string Branch_precision;public string getbranch_addr () {return branch_addr;} public void Setbranch_addr (String branch_addr) {this.branch_addr = branch_addr;} Public String Getbranch_userid () {return branch_userid;} public void Setbranch_userid (String branch_userid) {this.branch_userid = Branch_userid;} Public String getbranch_id () {return branch_id;} public void setbranch_id (String branch_id) {this.branch_id = branch_id;} Public String Getbranch_name () {return branch_name;} public void Setbranch_name (String branch_Name) {this.branch_name = Branch_name;} Public String getprovince () {return province;} public void Setprovince (String province) {this.province = province;} Public String getcity () {return city;} public void Setcity (String city) {this.city = city;} Public String Getbranch_status () {return branch_status;} public void Setbranch_status (String branch_status) {this.branch_status = Branch_status;} Public String Getbranch_latitude () {return branch_latitude;} public void Setbranch_latitude (String branch_latitude) {this.branch_latitude = Branch_latitude;} Public String Getbranch_longitude () {return branch_longitude;} public void Setbranch_longitude (String branch_longitude) {this.branch_longitude = Branch_longitude;} Public String Getis_default () {return is_default;} public void Setis_default (String is_default) {this.is_default = Is_default;} Public String Getbranch_phone () {return branch_phone;} public void Setbranch_phone (String branch_phone) {this.branch_phone = Branch_phone;} Public String Getbranch_creattiMe () {return branch_creattime;} public void Setbranch_creattime (String branch_creattime) {this.branch_creattime = Branch_creattime;} Public String Getbranch_park () {return branch_park;} public void Setbranch_park (String branch_park) {this.branch_park = Branch_park;} Public String Getbranch_guidelines () {return branch_guidelines;} public void Setbranch_guidelines (String branch_guidelines) {this.branch_guidelines = Branch_guidelines;} Public String Getbranch_updatetime () {return branch_updatetime;} public void Setbranch_updatetime (String branch_updatetime) {this.branch_updatetime = Branch_updatetime;} Public String getmerchant_id () {return merchant_id;} public void setmerchant_id (String merchant_id) {this.merchant_id = merchant_id;} Public String getbranch_precision () {return branch_precision;} public void Setbranch_precision (String branch_precision) {this.branch_precision = branch_precision;}}

After you have defined the above classes, you can start parsing the contents of the [] first, that is, parsing the array Gson parsing the array is as follows: OptJSONArray9 () method Jo returns the Jsonobject object to the server

Jsonarray Orderjsonarray = Jo.optjsonarray ("result");

After the above analysis, we get a Jsonarray object, this object can be based on the actual situation, continue to parse.

if (null! = orderjsonarray&& orderjsonarray.length () > 0) {for (int i = 0; i < orderjsonarray.length (); i++) {Jsonobject Cityjsonobject = Orderjsonarray.getjsonobject (i); Orderseatrows Orderrow = Gsonutils.toobject ( Cityjsonobject.tostring (), orderseatrows.class);

To facilitate Jsonarray objects, using the Getjsonobject () method, you can getall of the Jsonobject objects in Jsonarray have jsonobject objects that can parse the JSON into the previously defined object.
Summary:In the development of the general use of several data models, are introduced in the above, in fact, as long as a principle, see [] Resolution of the group, see {} Parsed into objects, then the complex JSON data can easily parse out the data we want, for the development of the next good data preparation.