我使用playframework并尝试将一些json反序列化为java对象。
工作正常,展示了模型中的关系。我有以下异常
enter code hereorg.codehaus.jackson.map.JsonMappingException: Can not instantiate value of type [simple type, class models.Job] from JSON String; no single-String constructor/factory method (through reference chain: models.Docfile["job"])
我以为 jackson 结合游戏可以做到这一点:
这是json
{"name":"asd","filepath":"blob","contenttype":"image/png","description":"asd","job":"1"}
这是我的代码,没什么特别的:
public static Result getdata(String dataname) {
ObjectMapper mapper = new ObjectMapper();
try {
Docfile docfile = mapper.readValue((dataname), Docfile.class);
System.out.println(docfile.name);
docfile.save();
} catch (JsonGenerationException e) {
e.printStackTrace();
} catch (JsonMappingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return ok();
}
希望对我有帮助,谢谢
马库斯
更新:
Docfile Bean:
package models;
import java.util.*;
import play.db.jpa.*;
import java.lang.Object.*;
import play.data.format.*;
import play.db.ebean.*;
import play.db.ebean.Model.Finder;
import play.data.validation.Constraints.*;
import play.data.validation.Constraints.Validator.*;
import javax.persistence.*;
import com.avaje.ebean.Page;
@Entity
public class Docfile extends Model {
@Id
public Long id;
@Required
public String name;
@Required
public String description;
public String filepath;
public String contenttype;
@ManyToOne
public Job job;
public static Finder<Long,Docfile> find = new Model.Finder(
Long.class, Docfile.class
);
public static List<Docfile> findbyJob(Long job) {
return find.where()
.eq("job.id", job)
.findList();
}
public static Docfile create (Docfile docfile, Long jobid) {
System.out.println(docfile);
docfile.job = Job.find.ref(jobid);
docfile.save();
return docfile;
}
}
最佳答案
您可以更改JSON来描述您的“工作”实体:
{
"name":"asd",
"filepath":"blob",
"contenttype":"image/png",
"description":"asd",
"job":{
"id":"1",
"foo", "bar"
}
}
或者您在Job Bean中使用String参数创建一个构造函数:
public Job(String id) {
// populate your job with its id
}
关于json - JSON字符串中的org.codehaus.jackson.map.JsonMappingException : Can not instantiate value of type [simple type,类模型。,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/11127376/