If the class does not have toString() method, then you can use ToStringBuilder class from org.apache.commons:commons-lang3

pom.xml:

<dependency>
  <groupId>org.apache.commons</groupId>
  <artifactId>commons-lang3</artifactId>
  <version>3.18.0</version>
</dependency>

build.gradle:

implementation 'org.apache.commons:commons-lang3:3.18.0'

code:

ToStringBuilder.reflectionToString(yourObject)

Might not be so related to the issue above. However if you are looking for a way to serialize Java object as string, this could come in hand

package pt.iol.security;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;
import org.apache.commons.codec.binary.Base64;

public class ObjectUtil {

    static final Base64 base64 = new Base64();

    public static String serializeObjectToString(Object object) throws IOException {
        try (
                ByteArrayOutputStream arrayOutputStream = new ByteArrayOutputStream();
                GZIPOutputStream gzipOutputStream = new GZIPOutputStream(arrayOutputStream);
                ObjectOutputStream objectOutputStream = new ObjectOutputStream(gzipOutputStream);) {
            objectOutputStream.writeObject(object);
            objectOutputStream.flush();
            return new String(base64.encode(arrayOutputStream.toByteArray()));
        }
    }

    public static Object deserializeObjectFromString(String objectString) throws IOException, ClassNotFoundException {
        try (
                ByteArrayInputStream arrayInputStream = new ByteArrayInputStream(base64.decode(objectString));
                GZIPInputStream gzipInputStream = new GZIPInputStream(arrayInputStream);
                ObjectInputStream objectInputStream = new ObjectInputStream(gzipInputStream)) {
            return objectInputStream.readObject();
        }
    }
}

Depends on what you really want to do, for example if you only want to get the value of a given key, given that key and value are separated by colon and key/value are separated by comma, you can just split in this way string first by comma and then by colon :

String[] couple = string.split(",");

 for(int i =0; i < couple.length ; i++) {
    String[] items =couple[i].split(":");
    items[0]; //Key
    items[1]; //Value
}

If you want to do it with a regular expression you can do in this way :

    String string = "Name:armand,Age:22,";
    Pattern pattern = Pattern.compile("(\\w+?):(\\w+?),");
    Matcher matcher = pattern.matcher(string);
    while (matcher.find()) {
        String key = matcher.group(1);
        String value = matcher.group(2);

        System.out.println("Key : " + key + " value : " + value);
    }

If you are using Java 8, you may modify the getValue method in the following way:

  public <T> T getValue(Function<Integer, T> parser) {
      return Optional.of(value).map(parser).get();
  }

Example:

  Register $t2 = new Register("t2.setValue(20);

  //getting values

  Long longValue = $t2.getValue(Integer::longValue);
  Double doubleValue = $t2.getValue(Integer::doubleValue);
  String stringValue = $t2.getValue(i -> i.toString());
  Integer integerValue = $t2.getValue(Integer::valueOf);
  System.out.print("long: " + longValue + ", double: " + doubleValue + ", string: " + stringValue + ", integer: " + integerValue);

Output: long: 20, double: 20.0, string: 20, integer: 20

It is hard to make out what you are asking, but you can fetch field values by name using reflection. Something like this:

    Class c = this.getClass();  // or Someclass.class
    Field f = c.getDeclaredField("xyz");
    String value = (String) f.get(this);
    ... = value.split("_");

(I've left out a lot of exception handling ...)

But as a comment points out, if you are really trying to implement an associative array, there are better ways of doing this in Java; e.g. using a Map class.

In ideal situations,Class does not hold data. It merely holds the information about the structure and behavior of its instances and Instances of the Classes hold your data to use. So your extractStringFromField method can not extract values unless you pass any instances (from where it will actually extract values).

If the name of the parameter of the reference, you are passing to extract value is instance, then you can easily get what you want like bellow:

String strValue = (String)field.get(instance);

... Hi Sam, You need to set the text of the second TextView before getting it. You can do this adding android:text to the second textview in the xml to have static text (the default value). To have dynamic text into your second textview just set the text when you are creating the element of the List. Hope this help.

Cheers

String array is needed if you want to print a list of string:

String[] Qty = {"1", "2"};
String qtyString = null;
for (int j = 0; i<=1; j++) {
    qtyString = Qty[j];
    System.out.println("qtyString = " + qtyString);
}

output:
qtyString = 1
qtyString = 2