Map To Inputstream Java

Stream map () is an intermediate operation used to apply one given function to the elements of a stream. Let's start with a simple example using java to do the conversion — using an. This function used for extracting the values of the map for the given key.

Using com.fasterxml.jackson.databind.objectmapper, we are converting the hashmap into json. Mapper is a stateless function which is applied to each element and the function returns the new stream. The syntax is as follows.

This is also part of intermediate operations such as map () and filter () methods.

These operations are always lazy. And writing/passing the data to another target that wants data in the input stream. Objectmapper is the main essential class in the jackson library that helps for reading and writing json, either to and from basic pojo’s (plain old java objects) or from hashmap containing key/value pairs. And we use fileoutputstream to copy the inputstream into a file, and save it somewhere.