Jackson - 注解 @JsonView：限制不同用户的字段显示

在 Jackson 中，我们可以使用@JsonView来限制或控制不同用户的字段显示。

@Data
public class Staff {
    
    private String name;
    private int age;
    private String[] position;
    private List skills;
    private Map salary;
    
}

一个标准的 Java 类，用于定义 3 个视角：normal、manager 和 hr。

public class CompanyViews {

    public static class Normal{};

    public static class Manager extends Normal{};

    public static class HR extends Normal{};

}

@JsonView置于字段级别以限制不同视角的字段显示。

• 正常 —— 显示姓名和年龄。
• 经理 —— 显示姓名、年龄、职位和技能
• HR —— 显示姓名、年龄、薪水和职位

@Data
public class Staff {

    @JsonView(CompanyViews.Normal.class)
    private String name;

    @JsonView(CompanyViews.Normal.class)
    private int age;

    // two views
    @JsonView({CompanyViews.HR.class, CompanyViews.Manager.class})
    private String[] position;

    @JsonView(CompanyViews.Manager.class)
    private List skills;

    @JsonView(CompanyViews.HR.class)
    private Map salary;
}

下面的例子，告诉你如何启用JsonView使用mapper.writerWithView()

public class JacksonExample1 {
    public static void main(String[] args) {

        ObjectMapper mapper = new ObjectMapper();

        Staff staff = createStaff();

        try {

            // to enable pretty print
            mapper.enable(SerializationFeature.INDENT_OUTPUT);

            // normal
            String normalView = mapper.writerWithView(CompanyViews.Normal.class).writeValueAsString(staff);

            System.out.format("Normal viewsn%sn", normalView);

            // manager
            String managerView = mapper.writerWithView(CompanyViews.Manager.class).writeValueAsString(staff);

            System.out.format("Manager viewsn%sn", managerView);

            // hr
            String hrView = mapper.writerWithView(CompanyViews.HR.class).writeValueAsString(staff);

            System.out.format("HR viewsn%sn", hrView);

        } catch (IOException e) {
            e.printStackTrace();
        }

    }

    private static Staff createStaff() {

        Staff staff = new Staff();

        staff.setName("mkyong");
        staff.setAge(38);
        staff.setPosition(new String[]{"Founder", "CTO", "Writer"});
        Map salary = new HashMap() {{
            put("2010", new BigDecimal(10000));
            put("2012", new BigDecimal(12000));
            put("2018", new BigDecimal(14000));
        }};
        staff.setSalary(salary);
        staff.setSkills(Arrays.asList("java", "python", "node", "kotlin"));

        return staff;

    }
}

输出：

Normal views
{
  "name" : "mkyong",
  "age" : 38
}

Manager views
{
  "name" : "mkyong",
  "age" : 38,
  "position" : [ "Founder", "CTO", "Writer" ],
  "skills" : [ "java", "python", "node", "kotlin" ]
}

HR views
{
  "name" : "mkyong",
  "age" : 38,
  "position" : [ "Founder", "CTO", "Writer" ],
  "salary" : {
    "2018" : 14000,
    "2012" : 12000,
    "2010" : 10000
  }
}