Java——jackson的注解@JsonProperty、@JsonIgnore、@JsonFormat、@JsonIgnoreProperties

zilin-lynn

已于 2022-04-18 17:56:20 修改

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分类专栏： java web 文章标签：序列化 jackson

于 2022-04-18 17:55:21 首次发布

本文链接：https://blog.youkuaiyun.com/lvyanqin2013/article/details/124255300

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这篇博客介绍了如何使用Jackson库将Java对象转换为JSON字符串，并展示了反序列化过程。通过`@JsonProperty`、`@JsonIgnore`、`@JsonFormat`和`@JsonIgnoreProperties`等注解，控制序列化和反序列化的细节。测试结果显示，注解成功地影响了字段的序列化和反序列化行为。

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1.使用

1.pom

<dependency> 
  <groupId>com.fasterxml.jackson.core</groupId> 
      <artifactId>jackson-databind</artifactId> 
  <version>2.11.0</version>
</dependency>

2.实体类 Student


import com.fasterxml.jackson.annotation.JsonFormat;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.annotation.JsonProperty;
import lombok.Data;

import java.io.Serializable;
import java.util.Date;

@Data
@JsonIgnoreProperties(value = { "address", "score" })
public class Student implements Serializable {

    @JsonProperty(value = "sName", required = true)
    private String name;

    @JsonIgnore
    private int age;

    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GTM+8")
    private Date birthday;

    private String address;

    private String score;

}

3.测试类

public class TestMain {

    public static void main(String[] args) throws JsonProcessingException {
        Student student = new Student();
        student.setName("张三");
        student.setAge(20);
        student.setBirthday(new Date());
        student.setAddress("上海市");
        student.setScore("90");

        // 使用writeValuesAsString把对象转化成json字符串。
        String stuJson = new ObjectMapper().writeValueAsString(student);
        System.out.println(stuJson);

        //使用readValue把字符串转化为对象
        Student stu = new ObjectMapper().readValue(stuJson, Student.class);
        System.out.println(stu.toString());

        System.out.println("==============================");

        String json1 = "{\"age\":20,\"birthday\":\"2022-04-18 09:38:47\",\"address\":\"上海市\",\"score\":\"90\",\"sName\":\"张三\"}";

        Student stu1 = new ObjectMapper().readValue(json1, Student.class);
        System.out.println(stu1.toString());
    }

}

测试结果：

{"birthday":"2022-04-18 09:42:58","sName":"张三"}
Student(name=张三, age=0, birthday=Mon Apr 18 17:42:58 CST 2022, address=null, score=null)
==============================
Student(name=张三, age=0, birthday=Mon Apr 18 17:38:47 CST 2022, address=null, score=null)