java判断list不为空的实现,和限制条数不要在一起写

// 记录不为空 && 只有一条 才继续
if(!CollectionUtils.isEmpty(list) && 1!=list.size()){
  return "记录条数不是1";
}
Object object = list.get(0);

import org.apache.commons.lang.StringUtils;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.FatalBeanException;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class IsNull {
  //整个类都校验
  public static List<String> validateProperty(Object validateObj) {
    return validateProperty(validateObj,(String[])null);
  }
  //类中的某些字段不校验
  public static List<String> validateProperty(Object validateObj,String... ignoreProperties) {
    PropertyDescriptor[] targetPds = BeanUtils.getPropertyDescriptors(validateObj.getClass());
    List<String> ignoreList = (ignoreProperties != null ? Arrays.asList(ignoreProperties) : null);
    List<String> errList = new ArrayList<>();
    for (PropertyDescriptor targetPd : targetPds) {
      Method readMethod = targetPd.getReadMethod();
      if (readMethod != null && (ignoreList == null || !ignoreList.contains(targetPd.getName()))) {
        try {
          if (!Modifier.isPublic(readMethod.getDeclaringClass().getModifiers())) {
            readMethod.setAccessible(true);
          }
          Object value = readMethod.invoke(validateObj);
          if (value instanceof String) {
            if (StringUtils.isEmpty((String) value)) {
              errList.add(validateObj.getClass().getSimpleName()+ "中的" + targetPd.getName() + "不能为空");
              continue;
            }
          }
          if (value instanceof Float || value instanceof Integer) {
            if (StringUtils.isEmpty(value.toString())) {
              errList.add(validateObj.getClass().getSimpleName()+ "中的" + targetPd.getName() + "不能为空");
              continue;
            }
          }
          if (value == null) {
            errList.add(validateObj.getClass().getSimpleName() + "中的" + targetPd.getName() + "不能为空");
          }
        } catch (Throwable ex) {
          throw new FatalBeanException(
              "Could not copy property '" + targetPd.getName() + "' from source to target", ex);
        }
      }
    }
    return errList;
  }
}