The following example illustrates Jackson streaming APIs for writing JSON data. This example reads a list of Employee objects, converts them into JSON representations, and then writes to the OutputStream object. The steps are as follows:

1. The following code snippet generates com.fasterxml.jackson.core.JsonGenerator by using com.fasterxml.jackson.core.JsonFactory:

OutputStream outputStream = new 
   FileOutputStream("emp-array.json");JsonGenerator jsonGenerator = new 
   JsonFactory().createGenerator(outputStream, 
     JsonEncoding.UTF8);

2. The next step is to build the JSON representation for the list of employees. The writeStartArray() method writes the starting marker for the JSON array ([). Now, write the marker for the object ({) by calling writeStartObject(). This is followed by the name-value pairs for the object by calling an appropriate write method. To write the end marker for the object (}), call writeEndObject(). Finally, to finish writing an array, call writeEndArray():

jsonGenerator.writeStartArray(); 
List<Employee> employees = getEmployeesList(); 
for (Employee employee : employees) { 
  jsonGenerator.writeStartObject(); 
  jsonGenerator.writeNumberField("employeeId", 
     employee.getEmployeeId());  jsonGenerator.writeStringField("firstName", 
     employee.getFirstName());  jsonGenerator.writeStringField("lastName", 
     employee.getLastName()); 
  jsonGenerator.writeEndObject(); 
 
} 
//JsonGenerator class writes the JSON content to the  
//specified OutputStream.  
 
jsonGenerator.writeEndArray(); 

3. Close the stream object after use:

//Close the streams to release associated resources 
jsonGenerator.close(); 
outputStream.close(); 

In the next section, we will discuss Gson, yet another framework for processing JSON.