JSON中提供了常用的对象和json数据间的转换方法。
JSONObject可以看作Map，使用key-value构建json对象。
JSONArray可以看作List，使用List可以简单构造json数组对象。1.pom.xml中引入依赖

<dependency><groupId>com.alibaba.fastjson2</groupId><artifactId>fastjson2</artifactId><version>2.0.29</version>
</dependency>

2.准备实体类
import com.alibaba.fastjson2.annotation.JSONField;
import lombok.Data;
import lombok.extern.slf4j.Slf4j;
import java.util.Date;@Slf4j
@Data
public class Person {@JSONField(name="AGE", serialize=false)private int age;@JSONField(name="LAST NAME", ordinal = 2)private String lastName;@JSONField(name="FIRST NAME", ordinal = 1)private String firstName;@JSONField(name="DATE OF BIRTH", format="dd/MM/yyyy", ordinal = 3)private Date dateOfBirth;public Person() {}public Person(int age, String lastName, String firstName, Date dateOfBirth) {this.age = age;this.lastName = lastName;this.firstName = firstName;this.dateOfBirth = dateOfBirth;}
}

3.准备测试类
import com.test.fastjson.to.Person;
import com.alibaba.fastjson2.JSON;
import com.alibaba.fastjson2.JSONArray;
import com.alibaba.fastjson2.JSONObject;
import com.alibaba.fastjson2.filter.NameFilter;
import lombok.extern.slf4j.Slf4j;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;import java.util.ArrayList;
import java.util.Date;
import java.util.List;import static org.junit.jupiter.api.Assertions.assertEquals;@Slf4j
class TestTest {private List<Person> listOfPersons = new ArrayList<>();@BeforeEachpublic void setUp() {listOfPersons.add(new Person(15, null,"Doe", new Date()));listOfPersons.add(new Person(20, "Janette Doe", "Kobe", new Date()));}/*** convert object to json String.*/@Testpublic void whenJavaList_thanConvertToJsonCorrect() {String jsonOutput= JSON.toJSONString(listOfPersons);log.info(jsonOutput);}/*** json string to object*/@Testpublic void whenJson_thanConvertToObjectCorrect() {Person person = new Person(20, "John", "Doe", new Date());String jsonObject = JSON.toJSONString(person);Person newPerson = JSON.parseObject(jsonObject, Person.class);assertEquals(newPerson.getAge(), 0); // 如果我们设置系列化为 falseassertEquals(newPerson.getFirstName(), listOfPersons.get(0).getFirstName());}/*** how to use JSONObject and JSONArray*/@Testpublic void whenGenerateJson_thanGenerationCorrect() {JSONArray jsonArray = new JSONArray();for (int i = 0; i < 2; i++) {JSONObject jsonObject = new JSONObject();jsonObject.put("AGE", 10);jsonObject.put("FULL NAME", "Doe " + i);jsonObject.put("DATE OF BIRTH", "2016/12/12 12:12:12");jsonArray.add(jsonObject);}String jsonOutput = jsonArray.toJSONString();log.info(jsonOutput);}/*** define NameFilter*/@Testpublic void givenSerializeConfig_whenJavaObject_thanJsonCorrect() {NameFilter formatName = new NameFilter() {public String process(Object object, String name, Object value) {return name.toLowerCase().replace(" ", "_");//FIRST NAME  ---> first_name}};String jsonOutput = JSON.toJSONString(listOfPersons, formatName);log.info(jsonOutput);}}