Get fields and their values at runtime using Java Reflection

Question

I am trying to get fields and their values of an object at runtime. Below is the code sample:

public static int calculateProfileStrenght(Object inputObj, Map<String, Integer> configMap) throws IllegalArgumentException, IllegalAccessException { int someValue= 0; for (Entry<String, Integer> entry : configMap.entrySet()) { System.out.println("Key=" + entry.getKey() + ", Value="+ entry.getValue()); try { Field field = inputObj.getClass().getDeclaredField(entry.getKey()); } catch (NoSuchFieldException e) { System.out.println("No such field: "+entry.getKey()); } } return someValue; }

As shown above, the Map contains key-value pairs, where the key is going to be the field name (or variable name) from inputObj. I need to read the value of this field from inputObj. The datatype of the fields are String, int, Date, etc. inputObj

 public class UserDetails { private int userId; private String userName; private Date joinedDate; private Address homeAddress; private String description; // getters and setters }

I can't do field.getLong or getChar, etc since the method is generic and doesn't know about the datatypes of the fields of inputObj.

I need to read the field values in the for loop and apply the business logic. Is this even possible? I tried a lot of ways but to no luck. Any references/pointers are appreciated.

user2184773 · Accepted Answer · 2014-08-07 09:08:23Z

how about this method in Filed ：Object get(Object obj) this method returns the value of the field represented by this Field, on the specified object.

Pramod Karandikar · Accepted Answer · 2014-08-07 09:09:25Z

1

I missed field.get(Object) method. This will resolve the issue.

answered Aug 7, 2014 at 9:09

Pramod Karandikar

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Stack Exchange Broke The Law · Accepted Answer · 2014-08-07 09:02:40Z

field.getType() returns the type of the field (int.class, Date.class, etc). You can easily perform different actions depending on its return value.

Class<?> type = field.getType(); if(type == int.class) { // load an int } else if(type == Date.class) { // load a Date } else if(type == String.class) { // load a String } // etc

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