如何使用 Java 中的 ExclusionStrategy 接口序列化和反序列化 JSON?
javajsonobject oriented programmingprogramming
ExclusionStrategy 接口可用于在序列化和反序列化期间排除任何字段。我们可以提供 ExclusionStrategy 接口的自定义实现，并需要使用 setExclusionStrategies() 方法将其注册到 GsonBuilder 。它将 Gson 配置为在序列化和反序列化期间应用一组排除策略。
语法
public GsonBuilder setExclusionStrategies(ExclusionStrategy... strategies)
示例
import com.google.gson.*;
import com.google.gson.ExclusionStrategy;
import com.google.gson.FieldAttributes;
public class ExclusionStrategyTest {
public static void main(String args[]) throws Exception {
Gson gson = new GsonBuilder().setExclusionStrategies(new CustomExclusionStrategy()).create();
Person person = new Person();
person.setFirstName("Adithya");
person.setLastName("Sai");
person.setAddress("Hyderabad");
String jsonString = gson.toJson(person);
System.out.println("Serialize a JSON: \n "+jsonString);
String inputJson = "{\"firstName\":\"Raja\", \"lastName\":\"Ramesh\", \"address\":\"Hyderabad\"}";
person = gson.fromJson(inputJson, Person.class);
System.out.println("Deserialize a JSON:\n"+ person);
}
}
// CustomExclusionStrategy class
class CustomExclusionStrategy implements ExclusionStrategy {
public boolean shouldSkipField(FieldAttributes f) {
if(f.getName().equals("firstName")) {
return true;
}
return false;
}
public boolean shouldSkipClass(Class aClass) {
return false;
}
}
// Person class
class Person {
private String firstName, lastName, address;
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String geLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String toString() {
return "Person [" + firstName + " " + lastName + " " + address + "]";
}
}
输出
Serialize a JSON:
{"lastName":"Sai","address":"Hyderabad"}
Deserialize a JSON:
Person [null Ramesh Hyderabad]
