How to get the value of a field in a class using the field name?

Question

Java

There is a model object with a bunch of fields. It is necessary to compare it with another object, but not for all fields, but only for selective ones. How can I find out the value of a field by, for example, the name of the field so that later it can be compared?

Answer 1

https://docs.oracle.com/javase/tutorial/reflect/me...

Answer 2

//has object
Class<? extends Object> clazz = object.getClass();
Field[] fields = clazz.getDeclaredFields();
for(Field field: fields){
    String fieldName = field.getName();
    if(!field.isAccessible()){
        field.setAccessible(true);
    }
    Object value = field.get(object);
}

Answer 3

Well, somehow through java reflection

// Одно поле
Class c = obj.getClass(); 
Field nameField = c.getField("name");
// Или все поля
Class c = obj.getClass(); 
Field[] publicFields = c.getFields(); 
for (Field field : publicFields) { 
    Class fieldType = field.getType(); 
    System.out.println("Имя: " + field.getName()); 
    System.out.println("Тип: " + fieldType.getName()); 
}

Read more here www.quizful.net/post/java-reflection-api for example.

Answer 4

Class class = instance.getClass();
Field field = class.get("field name");
"field type" value = field.get(instance);
Get the value of the field. In general, it is not clear from the question what is known at the stage of writing the code.