CODEWITHSUNDEEP
java
Surya
Surya

Reputation: 426

convert object to string getting can not cast error

I have a list of object List in which at 4th index it has list of integer [1,2,3,4,5] Now I want to get list into a comma separated string. below is my try, but it giving error as can not cast.

for(Object[] objArr : relationshipInfo){
if(null != objArr[4]){
String groupedItemIds = (String)objArr[4];
}

how to do this?

Upvotes: 0

Views: 122

Answers (9)

Surya
Surya

Reputation: 426

I resolved my problem by belwo code

byte[] groupedItemIdsArr = (byte[])objArr[4];
String groupedItemIds = new String(groupedItemIdsArr);

Upvotes: 0

Scary Wombat
Scary Wombat

Reputation: 44854

Integer Array or Integer can not be cast to a String.

try 

for(Object[] objArr : relationshipInfo){
if(null != objArr[4]){
 String groupedItemIds =  new String (objArr[4]); // or String.valueOf(objArr[4]);
}

Update

If the 4th index is a Array then try 

String groupedItemIds = Arrays.asList(objArr[4]).toString();

which will give you a comma delimitered String

Upvotes: 0

Mitesh Pathak
Mitesh Pathak

Reputation: 1211

Try the following:- use toString()

String output = relationshipInfo.toString();
output = output.replace("[", "");
output = output.replace("]", "");
System.out.println(output);


[UPDATE]

If you want fourth Object only then try:

    Object[] objArr = relationshipInfo.toArray();
    String groupedItemIds = String.valueOf(objArr[4]);

Upvotes: 1

Vineet Kasat
Vineet Kasat

Reputation: 1014

You cannot cast an Object to an uncomatible type

for(Object[] objArr : relationshipInfo){
if(null != objArr[4]){
List<Integer> groupedItemIds = (List<Integer)objArr[4];;

//Loop over the integer list
}

Upvotes: 0

djsutho
djsutho

Reputation: 5834

It looks like you are using arrays not Lists in which case you can use:

String groupedItemIds = java.util.Arrays.toString(objArr[4]);

Upvotes: 0

Yagnesh Agola
Yagnesh Agola

Reputation: 4659

Try this : 

for(Object[] objArr : relationshipInfo)
{
      if(null != objArr[4])
       {
          String groupedItemIds = String.valueOf(objArr[4]);
       }
}

Ref : 

public static String valueOf(Object obj)

Returns the string representation of the Object argument.
Link.

Difference between use of toString() and String.valueOf()

if you invoke toString() with a null object or null value, you'll get a NullPointerExcepection whereas using String.valueOf() you don't have to check for null value.

Upvotes: 0

Jurgen
Jurgen

Reputation: 2154

You could try:

String groupedItemIds = Arrays.asList( objArr[4] ).toString();

This will produce: groupedItemIds = "[1,2,3,4,5]"

Upvotes: 0

TheLostMind
TheLostMind

Reputation: 36304

you want "comma separated string" . So, you iterate over the 4th index and read each integer and do "" + int1 +" , " + int2 etc.. you can do this (in) by overriding your toString() method..

Upvotes: 0

Aniket Thakur
Aniket Thakur

Reputation: 68975

You cannot type cast Object to String unless the Object is indeed a String. Instead you can do the following -

Call toString() on it. Override it in your class.

Upvotes: 0

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