Convert data to JSON format

I. Using Gson to convert to JSON format
Dependent MAVEN Packages:

<dependency> <groupId>com.google.code.gson</groupId> <artifactId>gson</artifactId> <version>2.2.4</version></dependency>

The key code is as follows:

Import Com.google.gson.gson;import com.google.gson.gsonbuilder;import com.google.gson.jsonobject;//....        Gson Gson = new Gsonbuilder (). Create ();        Gson.tojson ("Hello", System.out);        Gson.tojson (123, System.out);        System.out.println ();        Jsonobject json = new Jsonobject ();        Json.addproperty ("DD", "22");        Json.addproperty ("DDS", 22); SYSTEM.OUT.PRINTLN (JSON);

Output:

"Hello" 123

{"DD": "$", "DDS": 22}

Second. Convert Json format using json-lib

Json-lib is a Java class library (official website: http://json-lib.sourceforge.net/) to achieve the following functions:

Convert JavaBeans, maps, collections, Java arrays, and XML into JSON format data

. convert JSON format data to a JavaBeans object

Json-lib Required JAR Package

• Commons-beanutils-1.8.3.jar

• Commons-collections-3.2.1.jar

• Commons-lang-2.6.jar

• Commons-logging-1.1.1.jar

• Ezmorph-1.0.6.jar

• Json-lib-2.4-jdk15.jar

Use of Json-lib

1. Parses an Array into a Json string. Use Jsonarray to parse the Array type:

package util.copy;import java.util.arraylist;import java.util.hashset;import  java.util.list;import java.util.set;import net.sf.json.jsonarray;import net.sf.json.jsonobject; Public class test {    public static void main (String[]  args)  {        JSONObject json2 = new  Jsonobject ();         json2.put ("ss",  "");         system.out.println (Json2);         //will  Array  parsing into  Json  string        string[] str = {   "Jack",  "Tom",  ", " true " };       jsonarray  json = jsonarray.fromobject (str); &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;SYSTEM.ERR.PRINTLN ( JSON); &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBsp;        //to image arrays, note numbers and cloth values         object[] o = {  "Beijing",  "Shanghai", 89, true, 90.87 };        json = jsonarray.fromobject (o);        SYSTEM.ERR.PRINTLN (JSON);        //Use collection Class         List<String> list = new ArrayList<String> ();        list.add ("Jack");        list.add ("Rose");        json = jsonarray.fromobject (list);       &NBSP;SYSTEM.ERR.PRINTLN (JSON);        //use  set  set         Set<Object> set = new HashSet<Object> ();       &nBsp;set.add ("Hello");        set.add (True);        set.add,        json = jsonarray.fromobject (set); &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;SYSTEM.ERR.PRINTLN (JSON);     }}

The results of the operation are as follows:

{"ss": "55"} ["Jack", "Tom", "All", "true"] ["Beijing", "Shanghai", 89,true,90.87] ["Jack", "Rose"] [99,true, "Hello"]

2. Parse the Javabean/map into a JSON string. Using Jsonobject parsing:

Public static void main (String[] args)  {             //Analysis  HashMap            Map<String, Object> map = new HashMap<String, Object> ();            map.put ("name",  "Tom");            map.put ("Age",  33);            jsonobject jsonobject = jsonobject.fromobject (map);            system.out.println (Jsonobject);                       // Parsing  javabean           person person =  new person ("A001",  "Jack");           jsonobject =  Jsonobject.fromobject (person);            System.out.println (Jsonobject);                       //Parsing nested objects             map.put ("person",  person);            jsonobject = jsonobject.fromobject (map);            system.out.println (jsonobject);     }

The results of the operation are as follows:

{"Age": $, "name": "Tom"} {"id": "A001", "name": "Jack"} {"Person": {"id": "A001", "name": "Jack"}, "Age": "," "Name": "Tom"}

3. Using the Jsonconfig-over property: for Javabean/map

public static void Main (string[] args) {jsonconfig config = new Jsonconfig ();  Config.setexcludes (new string[] {"Name"});       Specifies which properties are not included in the conversion when the person person = new Person ("A001", "Jack"); Jsonobject jsonobject = jsonobject.fromobject (person, config);   Pass in the previous configuration object System.out.println (Jsonobject) at the time of conversion; }

The result of the operation is as follows, and we can see that the name attribute is filtered out in the running result:

{"id": "A001"}

4. Convert the Json string to an Array:

public static void Main (string[] args) {Jsonarray Jsonarray = Jsonarray.fromobject ("[89,90,99]");       Object array = Jsonarray.toarray (Jsonarray);       SYSTEM.OUT.PRINTLN (array);   System.out.println (Arrays.aslist ((object[]) array); }

The results of the operation are as follows:

[Ljava.lang.object;@1e5003f6[89, 90, 99]

5. Turn the Json string into Javabean/map:

Public static void main (String[] args)  {             //convert strings in  Json  form to  Map             String str =  "{\" name\ ": \" tom\ ", \" age\ ":";    "         jsonobject jsonobject = jsonobject.fromobject ( STR);            map<string, object> map  =  (map<string, object>)  jsonobject.tobean (jsonobject, map.class);   &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;SYSTEM.OUT.PRINTLN (map);                       //will string conversion to  javabean           str in  Json  form  =  "{\" id\ ": \" A001\ ", \" name\ ": \" Jack\ "}";            jsonobject =  jsonobject.fromobject (str);            System.out.println (Jsonobject);           person  person =  (person)  jsonobject.tobean (jsonobject, person.class);     &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;SYSTEM.OUT.PRINTLN (person);     }

The results of the operation are as follows:

{age=90, Name=tom} person [id=a001, Name=jack]

When converting a Json-like string to JavaBean, it is important to note that there must be no parameter constructor in the JavaBean, or the following error cannot be found for the initialization method:

Exception in thread "main" Net.sf.json.jsonexception:java.lang.nosuchmethodexception:cn.sunzn.json.person.<init   > () at Net.sf.json.JSONObject.toBean (jsonobject.java:288) at Net.sf.json.JSONObject.toBean (jsonobject.java:233) At Cn.sunzn.json.JsonLib.main (jsonlib.java:23) caused By:java.lang.NoSuchMethodException:cn.sunzn.json.Person. <init> () at Java.lang.Class.getConstructor0 (Unknown Source) at Java.lang.Class.getDeclaredConstructor (Unknown Source) at Net.sf.json.util.newbeaninstancestrategy$defaultnewbeaninstancestrategy.newinstance ( newbeaninstancestrategy.java:55) at Net.sf.json.JSONObject.toBean (jsonobject.java:282) ... 2 more

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Convert data to JSON format