com.zhucan.jpa.conversion.converter.AbstractJsonConverter Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of spring-boot-starter-jpa-conversion Show documentation

Demo project for Spring Boot

The newest version!

package com.zhucan.jpa.conversion.converter;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.ObjectReader;
import com.fasterxml.jackson.databind.ObjectWriter;
import com.fasterxml.jackson.databind.SerializationFeature;
import org.springframework.beans.factory.annotation.Autowired;

import javax.persistence.AttributeConverter;
import javax.persistence.Converter;
import java.io.IOException;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

/**
 * @author: zhuCan
 * @date: 2019-07-17 16:17
 * @description: 通用型 实体类jsonBean <--> json 字段 转换基类
 * 使用方式 :
 * 1. 在实体类的字段上面 @Convert(Converter=子类.class)
 * 2. 在子类上加入 @Converter(autoApply = true), 可开启jpa全局自动转换
 */
public abstract class AbstractJsonConverter implements AttributeConverter {

  protected static ObjectMapper objectMapper;

  @Autowired
  public void setObjectMapper(ObjectMapper objectMapper) {
    AbstractJsonConverter.objectMapper = objectMapper;
  }

  @Override
  public String convertToDatabaseColumn(T attribute) {
    objectMapper.setConfig(objectMapper.getSerializationConfig().without(SerializationFeature.FAIL_ON_EMPTY_BEANS));
    ObjectWriter writer = objectMapper.writerFor(getJsonType());
    try {
      return writer.writeValueAsString(attribute);
    } catch (JsonProcessingException e) {
      e.printStackTrace();
      return null;
    }
  }

  @Override
  public T convertToEntityAttribute(String dbData) {
    ObjectReader reader = objectMapper.readerFor(getJsonType());
    try {
        // null 直接返回,不然会异常
      return dbData == null ? null : reader.readValue(dbData);
    } catch (IOException e) {
      e.printStackTrace();
      return null;
    }
  }

  /**
   * 获取子类中 json 转换的 TypeReference
   *
   * @return TypeReference
   */
  protected TypeReference getJsonType() {
    Type[] actualTypeArguments = ((ParameterizedType) (getClass().getGenericSuperclass())).getActualTypeArguments();
    if (actualTypeArguments != null && actualTypeArguments.length > 0) {
      return new TypeReference() {
        @Override
        public Type getType() {
          return actualTypeArguments[0];
        }

      };
    }

    return null;
  }
}