java jpa save方法更新數據工具類
- 因爲jpa沒有單獨更新某些字段的方法,save方法可以更新某條數據,但是有一個缺陷,就是它會將爲空的字段也更新上去.
如果有一個工具類可以將一個實體類非空的數據映射到jpa的findOne數據上,再進行save,就會方便很多.如下:
import com.alibaba.druid.util.StringUtils;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.BeanWrapper;
import org.springframework.beans.BeanWrapperImpl;
import java.beans.PropertyDescriptor;
import java.util.HashSet;
import java.util.Objects;
import java.util.Set;
public class UpdateUtil {
/**
* 所有爲空值的屬性都不copy
*
* @param source
* @param target
*/
public static void copyNullProperties(Object source, Object target) {
BeanUtils.copyProperties(source, target, getNullField(source));
}
/**
* 獲取屬性中爲空的字段
*
* @param target
* @return
*/
private static String[] getNullField(Object target) {
BeanWrapper beanWrapper = new BeanWrapperImpl(target);
PropertyDescriptor[] propertyDescriptors = beanWrapper.getPropertyDescriptors();
Set<String> notNullFieldSet = new HashSet<>();
if (propertyDescriptors.length > 0) {
for (PropertyDescriptor p : propertyDescriptors) {
String name = p.getName();
Object value = beanWrapper.getPropertyValue(name);
if (Objects.isNull(value)) {
notNullFieldSet.add(name);
}
}
}
String[] notNullField = new String[notNullFieldSet.size()];
return notNullFieldSet.toArray(notNullField);
}
public static void main(String[] args) {
IdNameVo newvo= new IdNameVo();
newvo.setId("1");
newvo.setName("更新後的實體類");
newvo.setLevel(1);
newvo.setParentId("0");
IdNameVo old= new IdNameVo();
old.setId("1");
old.setName("更新前的實體類");
old.setLevel(2);
old.setParentId("1");
old.setIdx(4);
old.setCode("123");
System.out.println(old);
UpdateUtil.copyNullProperties(newvo,old);
System.out.println(old);
//然後直接jpa的save(vo2)就可以了
}
}
輸出的結果爲:
IdNameVo(id=1, name=更新前的實體類, parentId=1, level=2, idx=4, children=[],code=123, coupon=null, couponId=null, promotionId=null,
promotionType=null, searchType=null)
IdNameVo(id=1, name=更新後的實體類, parentId=0, level=1, idx=4, children=[], code=123, coupon=null, couponId=null, promotionId=null,
promotionType=null, searchType=null)