英文:
Getting the list of fields that will be serialized by Jackson
问题
我正在尝试以编程方式获取在使用Jackson序列化器进行序列化的类中字段的列表。
我可以基于反射编写代码，遍历类中的字段，以查看哪些字段是公共的，具有getter/setter，或具有Jackson特定的注解等，并根据Jackson遵循的规则列出字段列表，以决定是否对字段进行序列化。但是实现很可能会不完整。
是否有使用Jackson库可以实现这一点的方法？
英文:
I am trying to programmatically get the list of fields in a class that will be serialized while using Jackson serializer.
I can write code based on reflection to go over the fields in the class to see which ones are public, have getter/setter, or have Jackson specific annotations, etc. and come up with a list as per the rules followed by Jackson to decide whether a field will be serialized. But there is a good chance that the implementation will be incomplete.
Is there any way using the Jackson library that I can achieve this?
答案1
得分: 3
你可以尝试使用 findValueSerializer 方法找到默认的 Bean 序列化器，并列出所有属性。以下是示例代码：
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.io.IOException;
public class JsonApp {
public static void main(String[] args) throws IOException {
ObjectMapper mapper = new ObjectMapper();
JsonSerializer<Object> serializer = mapper.getSerializerProviderInstance().findValueSerializer(Result.class);
serializer.properties().forEachRemaining(p -> {
System.out.println(p);
});
}
}
class Result {
@JsonIgnore
private int id = 1;
private String name = "Jack";
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@JsonProperty("id")
public String getIdAsString() {
return "ID:" + id;
}
}
以上代码会输出：
property 'name' (via method com.celoxity.Result#getName, static serializer of type com.fasterxml.jackson.databind.ser.std.StringSerializer)
property 'id' (via method com.celoxity.Result#getIdAsString, static serializer of type com.fasterxml.jackson.databind.ser.std.StringSerializer)
英文:
You can try to find default bean serialiser using findValueSerializer and list all properties. See below example:
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.io.IOException;
public class JsonApp {
public static void main(String[] args) throws IOException {
ObjectMapper mapper = new ObjectMapper();
JsonSerializer<Object> serializer = mapper.getSerializerProviderInstance().findValueSerializer(Result.class);
serializer.properties().forEachRemaining(p -> {
System.out.println(p);
});
}
}
class Result {
@JsonIgnore
private int id = 1;
private String name = "Jack";
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@JsonProperty("id")
public String getIdAsString() {
return "ID:" + id;
}
}
Above code prints:
property 'name' (via method com.celoxity.Result#getName, static serializer of type com.fasterxml.jackson.databind.ser.std.StringSerializer)
property 'id' (via method com.celoxity.Result#getIdAsString, static serializer of type com.fasterxml.jackson.databind.ser.std.StringSerializer)
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