springboot~ObjectMapper~dto到entity的自动赋值

import org.springframework.beans.beanutils;

beanutils.copyproperties(origin, target);

import com.fasterxml.jackson.databind.deserializationfeature;

import com.fasterxml.jackson.databind.objectmapper;

import com.fasterxml.jackson.databind.objectreader;

import com.jd.fastjson.json;

objectmapper objectmapper = new objectmapper();

//配置该objectmapper在反序列化时，忽略目标对象没有的属性。凡是使用该objectmapper反序列化时，都会拥有该特性。

objectmapper.configure(deserializationfeature.fail_on_unknown_properties, false );

//读入需要更新的目标实体

objectreader objectreader = objectmapper.readerforupdating(target);

//将源实体的值赋值到目标实体上

objectreader.readvalue(json.tojsonstring(source));

/*

  通过该方法对mapper对象进行设置，所有序列化的对象都将按改规则进行系列化

  include.include.always 默认

  include.non_default 属性为默认值不序列化

  include.non_empty 属性为 空（[]） 或者为 null 都不序列化

  include.non_null 属性为null 不序列化

  */

   objectmapper.setserializationinclusion(jsoninclude.include.non_default);

   string outjson = objectmapper.writevalueasstring(productdetail);

//上面代码里，outjson的值将会过滤掉只有默认值的属性

@requestmapping (value = "/{id}" , method = requestmethod.put)

public httpentity update( @pathvariable int id, @requestbody productdetail productdetail)

   throws ioexception {

  productdetail existing = repository.findbyid(id).get();

  objectmapper.setserializationinclusion(jsoninclude.include.non_default);

  string outjson = objectmapper.writevalueasstring(productdetail);

  objectreader objectreader = objectmapper.readerforupdating(existing);

  objectreader.readvalue(outjson);

  repository.save(existing);

  return new responseentity<>(existing, httpstatus.accepted);

}