Json string not formatted in browser but formatted in console

I am trying to output object serialized to json like this

@GetMapping("/person")
public String getPerson() throws JsonProcessingException {
    mapper.enable(SerializationFeature.INDENT_OUTPUT);
    System.out.println(mapper.writeValueAsString(person)); //just for debug
    return mapper.writeValueAsString(person);
}

I get what I wish in console:

{
  "name" : "person",
  "age" : 29,
  "listSkills" : [ "s1", "s2", "s3" ],
  "id" : 1,
  "hashCode" : 2145420209
} 

but in browser it is printed in one line and just gets different font

{ "name" : "person", "age" : 29, "listSkills" : [ "s1", "s2", "s3" ], "id" : 1, "hashCode" : 2145420209 }

Solution 1:

Problems

1. You expect browser to have the same font(and colors) as console!? (Your expectations "base on wrong assumptions"/you must care)
2. You don't use @[Rest]Controller as intended/documented.
3. Obviously ResponseBody<String> (which you in fact return) doesn't behave as expected regarding white space.

Solution

1. Spring-boot-starter-web [x]

2. application.properties:

   spring.jackson.serialization.indent_output=true
   

3. Impl:

   • Person:

     package com.example.webtest;
     import java.time.LocalDate;
     
     public class Person {
        private String name;
        private LocalDate date;
        // default constructor (implicit)
        // getters, setters:
        public String getName() {
          return name;
        }
        public Person setName(String name) {
          this.name = name;
          return this; // fluent api (not mandatory...)
        }
        public LocalDate getDate() {
          return date;
        }
        public Person setDate(LocalDate date) {
          this.date = date;
          return this;
        }
     }
     

   • Application + Controller:

     package com.example.webtest;
     
     import java.time.LocalDate;
     import org.springframework.boot.SpringApplication;
     import org.springframework.boot.autoconfigure.SpringBootApplication;
     import org.springframework.web.bind.annotation.GetMapping;
     import org.springframework.web.bind.annotation.RestController;
     
     @SpringBootApplication
     public class WebTestApplication {
     
        public static void main(String[] args) {
          SpringApplication.run(WebTestApplication.class, args);
        }
     
        @RestController
        static class SomeController {
     
          @GetMapping("/hello")
          public Person hello() { // Person! not String ;)
            return new Person().setName("Joe").setDate(LocalDate.now());
          }
        }
     }
     

4. Test (spring-boot:run,..browser) at http://localhost:8080/hello:

   

Key points

• Using spring-boot "jacksonObjectMapper" (auto & properties config).
• Returning the desired type and not a String.