Read JSON String from POST request in Spring Boot

This post will discuss how to read JSON string from POST request in Spring Boot.

Reading JSON string from POST request in Spring Boot is a common task that involves receiving and parsing a JSON payload from an HTTP request. JSON stands for JavaScript Object Notation, and it is a lightweight and human-readable format for exchanging data. Spring Boot is a framework that simplifies the development of web applications using the Spring framework.

There are different ways to read JSON string from POST in Spring Boot, depending on the structure and complexity of the JSON payload, as well as the desired format of the output. Here are some of the possible methods:

1. Using `@RequestBody` Annotation

This is a simple and standard way to read JSON string from POST in Spring Boot. The @RequestBody annotation binds the body of the HTTP request to a method parameter. The parameter can be of any type that can be converted from JSON, such as a String, a Map, or a custom class. Spring Boot uses Jackson library to perform the conversion automatically. For example:

// Import the annotation

import org.springframework.web.bind.annotation.RequestBody;

// Define a controller class

@RestController

@RequestMapping("/myservice")

public class MyServiceController

{

// Define a handler method that receives a POST request

@PostMapping("/process")

public void process(@RequestBody String payload)

{

// The payload parameter contains the JSON string from the request body

System.out.println(payload);

}

2. Using `ObjectMapper` Class

This is another way to read JSON string from POST in Spring Boot. The ObjectMapper class is a part of Jackson library that provides functionality for reading and writing JSON. We can use this class to parse a JSON string into an object of any type, such as a Map, a List, or a custom class. For example:

// Import the class

import com.fasterxml.jackson.databind.ObjectMapper;

// Define a controller class

@RestController

@RequestMapping("/myservice")

public class MyServiceController

{

// Define an ObjectMapper instance

private final ObjectMapper mapper;

// Inject the instance using constructor injection

public MyServiceController(ObjectMapper mapper) {

this.mapper = mapper;

}

// Define a handler method that receives a POST request

@PostMapping("/process")

public void process(@RequestBody String payload) throws IOException

{

// Use the mapper to parse the JSON string into a Map object

Map<String, Object> map = mapper.readValue(payload, new TypeReference<Map<String, Object>>() {});

// Print the map contents

System.out.println(map);

}

That’s all about reading JSON string from POST request in Spring Boot.

Read JSON String from POST request in Spring Boot

1. Using @RequestBody Annotation

2. Using ObjectMapper Class

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1. Using `@RequestBody` Annotation

2. Using `ObjectMapper` Class