java统计实体类中空字段数量

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package org.example; import java.lang.reflect.Field; /**  * @author 50649  */ public class TestCount {     public static int countNullFields(Object entity) throws IllegalAccessException {         if (entity == null) {             return 0;         }         int nullFieldCount = 0;         Class<?> clazz = entity.getClass();         Field[] fields = clazz.getDeclaredFields();         for (Field field : fields) {             field.setAccessible(true);             Object fieldValue = field.get(entity);             if (fieldValue == null) {                 nullFieldCount++;             }         }         return nullFieldCount;     }       public static void main(String[] args) throws IllegalAccessException {         // 假设有一个实体类 Entity 如下：         // class Entity {         //     String name;         //     Integer age;         //     String email;         // }         Entity entity = new Entity();         entity.name = "John";         entity.email = null;           int nullFieldCount = countNullFields(entity);         System.out.println("Number of null fields: " + nullFieldCount);     } }

　　

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package org.example;   /**  * @author 50649  */ public class Entity {     String name;     Integer age;     String email; }