Java判断对象属性是否为空 Java 判断实体对象及所有属性是否为空的操作

package com.liuxd.object; 
import org.apache.commons.lang3.StringUtils; 
import java.lang.reflect.Field;
 
/**
 * Created by Liuxd on 2018/11/2.
 */
public class TestEntity {
 
 public static void main(String[] args) {
 User user1 = new User("Jack", "male", 17);
 User user2 = new User();
 
 boolean u1Flag = checkObjAllFieldsIsNull(user1);
 boolean u2Flag = checkObjAllFieldsIsNull(user2);
 
 System.out.println("user1 是否为空：" + u1Flag);
 System.out.println("user2 是否为空：" + u2Flag); 
 }
 
 /**
 * 判断对象中属性值是否全为空
 *
 * @param object
 * @return
 */
 public static boolean checkObjAllFieldsIsNull(Object object) {
 if (null == object) {
  return true;
 }
 
 try {
  for (Field f : object.getClass().getDeclaredFields()) {
  f.setAccessible(true);
 
  System.out.print(f.getName() + ":");
  System.out.println(f.get(object));
 
  if (f.get(object) != null && StringUtils.isNotBlank(f.get(object).toString())) {
   return false;
  }
 
  }
 } catch (Exception e) {
  e.printStackTrace();
 }
 
 return true;
 }
}

package com.liuxd.object;
 
/**
 * Created by Liuxd on 2018/11/2.
 */
public class User { 
 private String name; 
 private String gender;
 
 /**
 * 如果属性类型为基本数据类型，则会有默认值
 * 影响正确判断，请特别注意
 */
// private int age; 
 private Integer age; 
 public User() {
 }
 
 public User(String name, String gender, int age) {
 this.name = name;
 this.gender = gender;
 this.age = age;
 }
 
 public String getName() {
 return name;
 }
 
 public void setName(String name) {
 this.name = name;
 }
 
 public String getGender() {
 return gender;
 }
 
 public void setGender(String gender) {
 this.gender = gender;
 }
 
 public Integer getAge() {
 return age;
 }
 
 public void setAge(Integer age) {
 this.age = age;
 }
}

name:Jack
name:null
gender:null
age:null
user1 是否为空：false
user2 是否为空：true

/**
 *判断一个实体类对象实例的所有成员变量是否为空
 *@param obj 校验的类对象实例
 *@return List 
 *@throws Exception
 */

public static List<String> isObjectFieldEmpty(Object obj) throws Exception {
 Class<?> clazz=obj.getClass(); //得到类对象
 Field[] fs=clazz.getDeclareFields(); //得到属性集合
 List<String> list=new ArrayList<String>();
 for(Field field:fs){      //遍历属性
   field.setAccessible(true); //设置属性是可以访问的（私有的也可以）
   if(field.get(obj)==null||field.get(obj)==""||"null".equalsIngnoreCase(String)field.get(obj))){
  String name=(String)field.getName();
  list.add(name);
  }
 }
 return list;
}