java序列化物件根據不同設定動態改變屬性名的方法

2022-05-25 18:01:37

實現方式

使用自定義註解和fastjson實現需求

fastjson的NameFilter的作用：序列化時，屬性名變成自己指定的名稱

實現過程

自定義註解一：MyParamName

package xin.yangshuai.cipher.json;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * MyParamName
 *
 * @author shuai
 * @date 2021/3/23
 */
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD, ElementType.FIELD, ElementType.PARAMETER})
public @interface MyParamName {

    String value() default "";

    NameEle[] names() default {};
}

value、names都是非必填

value：預設序列化的名稱

names：自定義註解二，陣列形式

自定義註解二：NameEle

package xin.yangshuai.cipher.json;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * NameEle
 *
 * @author shuai
 * @date 2021/3/24
 */
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD, ElementType.FIELD, ElementType.PARAMETER})
public @interface NameEle {
    String id();
    String value();
}

id：唯一標識，確定序列化後的屬性名

value：定義序列化後的屬性名

手寫MyNameFilter，實現fastjson的NameFilter

package xin.yangshuai.cipher.json;

import com.alibaba.fastjson.serializer.NameFilter;

import java.lang.reflect.Field;

/**
 * MyNameFilter
 *
 * @author shuai
 * @date 2021/3/23
 */
public class MyNameFilter implements NameFilter {

    private String id;

    public MyNameFilter() {
    }

    public MyNameFilter(String id) {
        this.id = id;
    }

    @Override
    public String process(Object o, String name, Object value) {
        try {
            Field field = o.getClass().getDeclaredField(name);
            MyParamName myParamName = field.getDeclaredAnnotation(MyParamName.class);
            NameEle[] nameEles = myParamName.names();
            String defaultName = myParamName.value();
            if (nameEles.length == 0 && defaultName.length() > 0) {
                return defaultName;
            }
            for (NameEle n : nameEles) {
                if (id.equals(n.id())) {
                    return n.value();
                }
            }
        } catch (Exception e) {
            return name;
        }
        return name;
    }
}

構造方法傳遞id屬性的值，與自定義註解二的id進行匹配，匹配成功則使用對應的屬性名

實體類，屬性上新增自定義註解

package xin.yangshuai.cipher.json;

import com.alibaba.fastjson.JSON;

/**
 * Person
 *
 * @author shuai
 * @date 2021/3/23
 */
public class Person {

    @MyParamName(names = {
            @NameEle(id = "ln", value = "i_d"),
            @NameEle(id = "jl", value = "_id")})
    private String id;

    @MyParamName("NAME")
    private String name;

    private String age;

    public String getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public String getAge() {
        return age;
    }

    public void setAge(String age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "Person{" +
                "id='" + id + ''' +
                ", name='" + name + ''' +
                ", age='" + age + ''' +
                '}';
    }
}

執行主方法測試

public static void main(String[] args) {
    Person person = new Person();
    person.setAge("18");
    person.setId("001");
    person.setName("張三");

    String s = JSON.toJSONString(person, new MyNameFilter("jl"));
    System.out.println(s);

    String s1 = JSON.toJSONString(person, new MyNameFilter("ln"));
    System.out.println(s1);
}