[[oktatas:programozás:java:java_json|< Java JSON]]

====== Java JSON - Moshi ======

  * **Szerző:** Sallai András
  * Copyright (c) 2025, Sallai András
  * Szerkesztve: 2025
  * Licenc: [[https://creativecommons.org/licenses/by-sa/4.0/|CC BY-SA 4.0]]
  * Web: https://szit.hu

===== Bevezetés =====

A Moshi egy Java programozói könyvtár JSON tartalmak kezelésére.

  * https://github.com/square/moshi


===== Beszerzés =====

==== Maven ====

<code xml>
<dependency>
    <groupId>com.squareup.moshi</groupId>
    <artifactId>moshi</artifactId>
    <version>1.15.2</version>
</dependency>
</code>



===== Employee osztály =====

<code java Employee.java>
package com.example;

public class Employee {
  private int id;
  private String name;
  private String city;
  private double salary;
  private String birth;

  public Employee() {}

  public Employee(int id, String name, String city, double salary, String birth) {
    this.id = id;
    this.name = name;
    this.city = city;
    this.salary = salary;
    this.birth = birth;
  }

  public Employee(String name, String city, double salary, String birth) {
    this.name = name;
    this.city = city;
    this.salary = salary;
    this.birth = birth;
  }

  public int getId() {
    return id;
  }

  public void setId(int id) {
    this.id = id;
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }

  public String getCity() {
    return city;
  }

  public void setCity(String city) {
    this.city = city;
  }

  public double getSalary() {
    return salary;
  }

  public void setSalary(double salary) {
    this.salary = salary;
  }

  public String getBirth() {
    return birth;
  }

  public void setBirth(String birth) {
    this.birth = birth;
  }
 
  
}

</code>

===== module-info.java =====

Ha van module-info.java fájl:

<code java module-info.java>
module com.example {
    requires javafx.controls;
    requires javafx.fxml;
    requires transitive javafx.graphics;
    requires com.squareup.moshi;

    opens com.example to javafx.fxml, com.squareup.moshi;
    
    exports com.example;
}
</code>


===== ArrayList-ből JSON string =====

<code java MainController.java>
import com.squareup.moshi.JsonAdapter;
import com.squareup.moshi.Moshi;

//...


Employee[] employeeArray = employeeList.toArray(new Employee[employeeList.size()]);

Moshi moshi = new Moshi.Builder().build();

JsonAdapter<Employee[]> jsonAdapter = moshi.adapter(Employee[].class).indent("  ");
      
String json = jsonAdapter.toJson(employeeArray);

</code>

===== JSON string-ből ArrayList =====

<code java MainController.java>
Employee[] employees2 = jsonAdapter.fromJson(json);
ArrayList<Employee> employeeList = new ArrayList<>(Arrays.asList(employees2));

System.out.println(employeeList.get(0).getName());

</code>

===== LocalDate használata =====

<code java LocalDateJsonAdapter>
package com.example;

import com.squareup.moshi.FromJson;
import com.squareup.moshi.ToJson;

import java.time.LocalDate;
import java.time.format.DateTimeFormatter;

public class LocalDateJsonAdapter {

    private static final DateTimeFormatter FORMATTER = DateTimeFormatter.ISO_LOCAL_DATE;

    @ToJson
    String toJson(LocalDate date) {
        return date.format(FORMATTER); 
    }

    @FromJson
    LocalDate fromJson(String date) {
        return LocalDate.parse(date, FORMATTER); 
    }

}
</code>

Használat:

<code java>
Moshi moshi = new Moshi.Builder()
    .add(new LocalDateJsonAdapter())
    .build();

JsonAdapter<Employee[]> jsonAdapter = moshi.adapter(Employee[].class).indent("  ");
</code>