Creating JSON String From Bean

I will use net.sf.json.* package for JSON processing. You can find the documentation and library files from here: http://json-lib.sourceforge.net/

Suppose you have the following class:

public class UserInfo {               

    String id;
    String userName;
    String birthPlace;

    // getters and setters here!

}

First, let's create an instance:

UserInfo userInfo = new UserInfo();
userInfo.setId("BFASHRGHFG");
userInfo.setUserName("User1");
userInfo.setBirthPlace("Madrid");

You can create JSON formatted string from this class with the following line:

String resultJson = JSONObject.fromObject(userInfo).toString();

resultJson will be:

{ "id" : "BFASHRGHFG", "userName" : "User1", "birthPlace" : "Madrid" }

We may want some fields not to be included in resulting json string, then we will create a JsonConfig instance and set exclude list of this instance:

JsonConfig jsonConfig = new JsonConfig();
jsonConfig.setExcludes(new String[] { "id" });

Then we may use this configuration as another parameter to fromObject method:

String resultJson = JSONObject.fromObject(userInfo,jsonConfig).toString();

resultJson will be:

{ "userName" : "User1", "birthPlace" : "Madrid" }