<dependency>
<groupId>com.googlecode.json-simple</groupId>
<artifactId>json-simple</artifactId>
<version>1.1.1</version>
</dependency>
Create plain old java obj, something as simple as follows:
package com.memeanalytics.json_demo;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
public class DemoEntity {
private String name = "";
private Date createDate=new Date();
private boolean enabled=false;
private double value = 0;
private int count = 0;
public String getName()
{
return this.name;
}
public void setName(String name)
{
this.name=name;
}
public String getCreateDateString()
{
SimpleDateFormat formatter=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
return formatter.format(this.createDate);
}
public void setCreateDateString(String dateString)
{
SimpleDateFormat formatter=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
try {
this.createDate = formatter.parse(dateString);
} catch (ParseException e) {
e.printStackTrace();
}
}
public boolean isEnabled()
{
return this.enabled;
}
public void setEnabled(boolean enabled)
{
this.enabled=enabled;
}
public int getCount()
{
return this.count;
}
public int setCount(int count)
{
return this.count = count;
}
public double getValue()
{
return this.value;
}
public void setValue(double value)
{
this.value=value;
}
}
Create a utility class with two methods to encode and decode between JSON and the DemoEntity obj:
package com.memeanalytics.json_demo;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
public class JsonEncoder {
public static String encode(DemoEntity obj)
{
JSONObject json=new JSONObject();
json.put("name", obj.getName());
json.put("createDate", obj.getCreateDateString());
json.put("value", obj.getValue());
json.put("count", obj.getCount());
return json.toJSONString();
}
public static DemoEntity decode(String jsonString)
{
JSONParser parser=new JSONParser();
DemoEntity obj=null;
try{
JSONObject json = (JSONObject)parser.parse(jsonString);
obj=new DemoEntity();
obj.setName((String)json.get("name"));
obj.setCreateDateString((String)json.get("createDate"));
obj.setValue((Double)json.get("value"));
obj.setCount(Integer.parseInt(json.get("count").toString()));
}catch(ParseException ex)
{
ex.printStackTrace();
}
return obj;
}
}
Now in the main class simply invokes the encode and decode methods to switch between JSON and DemoEntity obj:package com.memeanalytics.json_demo;
public class App
{
public static void main( String[] args )
{
DemoEntity obj=new DemoEntity();
obj.setName("obj1");
obj.setValue(12.5);
obj.setCount(10);
String jsonString = JsonEncoder.encode(obj);
System.out.println(jsonString);
DemoEntity obj2 = JsonEncoder.decode(jsonString);
if(obj2 != null)
{
System.out.println("name : " + obj2.getName());
System.out.println("created date : " + obj2.getCreateDateString());
System.out.println("value : "+obj2.getValue());
System.out.println("count : "+obj2.getCount());
}
}
}
Two points to note:
1. for Date() object, i will be safer to convert it to String before put it into a JSONObject during serialization, and vice versa in deserialization.
2. for Integer object, it will be safer to covert the the item returned by JSONObject.get() to a String then parse it to integer during deserialization (as JSONObject.get() usually will return a Long object instead of an Integer object).
Below is the link to the complete source codes:
https://dl.dropboxusercontent.com/u/113201788/storm/json-demo.zip
