Question

我正在尝试使用Jackson 2.9.8对实体进行序列化和反序列化，并且遇到了这个异常。

我的实体没有id属性，我正在使用父类的hashCode()方法。

我称之为SerializationId。

我得到的例外是：

原因：java.lang.IllegalStateException：已经有ID的POJO （java.lang.Integer）[[ObjectId：key = -23395637，类型= com.palmyra.test.TestIdGeneratorUMLX，范围= UMLX]] 在com.fasterxml.jackson.annotation.SimpleObjectIdResolver.bindItem（SimpleObjectIdResolver.java:24）

在JSON中，我在父级和子级中发现了SerializationId。

Answer 1

import java.util.Collection;
import java.util.Date;
import com.fasterxml.jackson.annotation.JsonIdentityInfo;
import com.fasterxml.jackson.annotation.ObjectIdGenerators;
@JsonIdentityInfo(generator = MyGenerator.class, property = "SerializationId ", scope = X.class)
public class X extends Z{
    private Map<String,Y> maps;

       // ... other columns, getters & setters
}
import java.util.Collection;
import java.util.Date;
import com.fasterxml.jackson.annotation.JsonIdentityInfo;
import com.fasterxml.jackson.annotation.ObjectIdGenerators;

@JsonIdentityInfo(generator = MyGenerator.class, property = "SerializationId ", scope = Y.class)
public class y extends Z{
    private Y myY;
       // ... other columns, getters & setters
}
import java.util.Collection;
import java.util.Date;
import com.fasterxml.jackson.annotation.JsonIdentityInfo;
import com.fasterxml.jackson.annotation.ObjectIdGenerators;
@JsonIdentityInfo(generator = MyGenerator.class, property = "SerializationId ", scope = Z.class)
public class Z {
    private String fullName;   
//this method return the hashcode of the fullName which is unique .
public int hashcode(){
}

       // ... other columns, getters & setters
}


public class MyGenerator extends ObjectIdGenerator<Z>{
generateId(forPojo){
//getting the hashcode
forPojo.hashcode();
}


}

JsonMappingException：已为（java.lang.Integer）使用POJO

1 个答案: