Jackson是Spring Boot默认的JSON数据处理框架，但是其并不依赖于任何的Spring 库。有的小伙伴以为Jackson只能在Spring框架内使用，其实不是的，没有这种限制。它提供了很多的JSON数据处理方法、注解，也包括

<dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-databind</artifactId><version>2.9.8</version>
</dependency>

@Data
public class PlayerStar {private String name;private Integer age;private String[] hobbies;    //业余爱好,数组private List<String> friends;   //  朋友private Map<String, BigDecimal> salary; //年收入 Map//初始化一个对象用于测试public static PlayerStar getInstance(){PlayerStar playerStar = new PlayerStar();playerStar.setName("乔丹");playerStar.setAge(45);playerStar.setHobbies(new String[]{"高尔夫球", "棒球"});Map<String, BigDecimal> salary = new HashMap<String, BigDecimal>() {{put("2000", new BigDecimal(10000000));put("2010", new BigDecimal(62000000));put("2020", new BigDecimal(112400000));}};playerStar.setSalary(salary);playerStar.setFriends(Arrays.asList("kobe", "curry", "james"));return playerStar;}}

@Test
void testObject2JSON() throws IOException {//获取对象实例PlayerStar player = PlayerStar.getInstance();//ObjectMapper作为Jackson的API工具类存在ObjectMapper mapper = new ObjectMapper();//将player对象以JSON格式进行序列化，并将序列化结果写入文件mapper.writeValue(new File("d:datajacksonplayer.json"), player);//将player对象以JSON格式进行序列化为String对象String jsonString = mapper.writeValueAsString(player);System.out.println(jsonString);//将player对象以JSON格式进行序列化为String对象(格式美化)String jsonInString2 = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(player);System.out.println(jsonInString2);
}

{"name":"乔丹","age":45,"hobbies":["高尔夫球","棒球"],"friends":["kobe","curry","james"],"salary":{"2000":10000000,"2010":62000000,"2020":112400000}}

{"name" : "乔丹","age" : 45,"hobbies" : [ "高尔夫球", "棒球" ],"friends" : [ "kobe", "curry", "james" ],"salary" : {"2000" : 10000000,"2010" : 62000000,"2020" : 112400000}
}

@Test
void testJSON2Object() throws IOException {ObjectMapper mapper = new ObjectMapper();//从文件中读取JSON字符串，反序列化为java对象PlayerStar player = mapper.readValue(new File("d:datajacksonplayer.json"), PlayerStar.class);System.out.println(player);//将JSON字符串反序列化为java对象String jsonInString = "{"name":"乔丹","age":45,"hobbies":["高尔夫球","棒球"]}";PlayerStar jordan = mapper.readValue(jsonInString, PlayerStar.class);System.out.println(jordan);}

PlayerStar(name=乔丹, age=45, hobbies=[高尔夫球, 棒球], friends=[kobe, curry, james], salary={2000=10000000, 2010=62000000, 2020=112400000})
PlayerStar(name=乔丹, age=45, hobbies=[高尔夫球, 棒球], friends=null, salary=null)

@Data
public class PlayerStar {@JsonProperty("playerName")private String name;  //将属性name序列化为playerName，同时影响反序列化

{"playerName":"乔丹"  ……

String jsonInString = "{"name":"乔丹","age":45,"hobbies":["高尔夫球","棒球"]}";
PlayerStar jordan = mapper.readValue(jsonInString, PlayerStar.class);

{"age" : 45,"hobbies" : null,"friends" : null,"salary" : null,"playerName" : "乔丹"
}

ObjectMapper mapper = new ObjectMapper();
mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);

@JsonInclude(JsonInclude.Include.NON_NULL)
public class PlayerStar {......
}

@JsonInclude(JsonInclude.Include.NON_NULL)
private String[] hobbies;    //业余爱好,数组
@JsonInclude(JsonInclude.Include.NON_NULL)
private List<String> friends;   //  朋友
@JsonInclude(JsonInclude.Include.NON_NULL)
private Map<String, BigDecimal> salary; //年收入 Map

{"age" : 45,"playerName" : "乔丹"
}

@Data
@JsonIgnoreProperties({"hobbies", "friends","salary"})
public class PlayerStar {@JsonProperty("playerName")private String name;private Integer age;@JsonIgnoreprivate String[] hobbies;    //业余爱好,数组@JsonIgnoreprivate List<String> friends;   //  朋友@JsonIgnoreprivate Map<String, BigDecimal> salary; //年收入 Map......

{"age" : 45,"playerName" : "乔丹"
}