Casting an object to string in java

Convert Object to String in Java

toString method is inherited from Object class. This tutorial introduces how to convert an object to a string in Java. Convert Object to String Using the Method in Java The method of the class can Convert an Object to a String.

Convert Object to String in Java

This tutorial introduces how to convert an object to a string in Java.

Convert Object to String Using the valueOf() Method in Java

The valueOf() method of the String class can Convert an Object to a String. See the example below.

public class SimpleTesting < public static void main(String[] args) < Object obj = "DelftStack Portal"; System.out.println("Object value: "+obj); String str = String.valueOf(obj); System.out.println("String value: "+str); >> 

Object value: DelftStack Portal String value: DelftStack Portal 

Convert Object to String Using the + Operator in Java

In Java, the plus operator + concatenates any type value with the string and returns a resultant string. We can use it to convert an object to a String too. See the below example.

public class SimpleTesting < public static void main(String[] args) < Object obj = "DelftStack Portal"; System.out.println("Object value: "+obj); String str = ""+obj; System.out.println("String value: "+str); >> 

Object value: DelftStack Portal String value: DelftStack Portal 

Convert Object to String Using the toString() Method in Java

The toString() method of the Object class converts any object to the string. See the below example.

public class SimpleTesting < public static void main(String[] args) < Object obj = "DelftStack Portal"; System.out.println("Object value: "+obj); String str = obj.toString(); System.out.println("String value: "+str); >> 

Object value: DelftStack Portal String value: DelftStack Portal 

Convert Object to String Using the toString() Method in Java

An object can be of any type. For example, if we have an integer object and want to get its string object, use the toString() method. See the example below.

public class SimpleTesting < public static void main(String[] args) < Integer iVal = 123; System.out.println("Integer Object value: "+iVal); String str = iVal.toString(); System.out.println("String value: "+str); >> 

Convert Object to String Using toString() Method in Java

This example explains how to convert a user-defined Object to a String using the toString() method. See the example below.

class Employee < String fName; String lName; public Employee(String fName, String lName) < this.fName = fName; this.lName = lName; >public String getfName() < return fName; >public void setfName(String fName) < this.fName = fName; >public String getlName() < return lName; >public void setlName(String lName) < this.lName = lName; >@Override public String toString() < return "Employee [fName=" + fName + ", lName=" + lName + "]"; >public String getString() < return toString(); >> public class SimpleTesting < public static void main(String[] args) < Employee employee = new Employee("Rohan","Mosac"); System.out.println(employee.getString()); >> 

Employee [fName=Rohan, lName=Mosac] 

Convert Object to String Using the join() Method in Java

Here, we convert an ArrayList Object to a string by using the join() method. The join() method of the String class returns a string after joining them into a single String object. See the example below.

import java.util.ArrayList; import java.util.List; public class SimpleTesting < public static void main(String[] args) < Listlist = new ArrayList<>(); list.add("Sun"); list.add("Moon"); list.add("Earth"); System.out.println("List object: "+list); // list object to string String str = String.join(",", list); System.out.println("String: "+str); > > 

List object: [Sun, Moon, Earth] String: Sun,Moon,Earth 

Java Object

Convert Object to String in Java, Convert Object to String Using the + Operator in Java In Java, the plus operator + concatenates any type value with the string and returns a resultant string. We can use it to convert an object to a string too. See the below example.

Java 8. Casting Object[] to String[][]

I’m trying to load data from file into JTable. So, using Java 8 streams it is very easy to load file into array of strings:

BufferedReader br = new BufferedReader(new FileReader(f)); Object[] data = br.lines().map((s)->< String[] res = ; // Here's some conversion of line into String[] - elements of one row return res; >).toArray(); TableModel m = new DefaultTableModel( (String[][])data, cols); 

If you use toArray(String[][]::new) instead of toArray() it will return a String[][] instead of an Object[] and you wont need to cast it at all (if you assign it to a String[][] ).

Splitting that piece of casting out into a loop should do it.

BufferedReader br = new BufferedReader(new FileReader(f)); Object[] data = br.lines().map((s)->< String[] res = ; // Here's some conversion of line into String[] - elements of one row return res; >).toArray(); String[][] dataMatrix = new String[data.length][]; for(int i = 0; i < data.length; i++)< dataMatrix[i] = (String[]) data[i]; >TableModel m = new DefaultTableModel(dataMatrix, cols); 

Convert object to Map in java, Please suggest how to convert an Object to Map in java. Tried org.apache.commons.beanutils.BeanMap(object). This is returning Map

Is it better to do toString() or cast the Object to String [duplicate]

Possible Duplicate:
(String) or .toString()?

I have an Object. Is it better to do like this

 final String params = myObject.toString(); 

 final String params =(String)myObject; 

ToString will work with all objects (as long as they are not null). If you cast to a string then the object has to be a String, otherwise it will fail. So my guess is that you want a toString() call, but it depends on what you want to do!

It depends what you’re trying to do.

When you cast the object to string like (String)myObject you’re actually trying to convert the object to a STRING, so you can get the class cast exception.

However, when calling myObject.toString you get a logical representation in String format of that object and it depends on implementation of toString() method of that object.

When you use (String)request.getAttribute(«buyertosellerpersoni d») request.getAttribute(«buyertosellerpersonid») returns you an object which you typecast into a String object. Incase the object that you’re trying to typecast isn’t actually a String object, you’ll get a ClassCastException. Make sure that you always set the attribute «buyertosellerpersonid» with a String value.

When you use request.getAttribute(«buyertosellerpersonid»).toString() the toString() method of the object returned by request.getAttribute(«buyertosellerpersonid») is called.

Now it depends on the implementation of the toString() method of this object as to what it will return. If it is a string that you’ve put in the attribute «buyertosellerpersonid» then you’ll get the String value. If it is anything else, then you’ll get the unsigned hexadecimal representation of its hashcode.

It is always a better idea to typecast the object. This makes sure that you always get the correct object, and it will throw an exception otherwise. You must catch such exceptions to ensure correct functioning of your program.

(String)myObject works fine only if myObject is instance of class String.

In the case of myObject.toString() calls toString() method of class myObject. toString method is inherited from Object class.

Java — Is it better to do toString() or cast the Object to, When you cast the object to string like (String)myObject you’re actually trying to convert the object to a string, so you can get the class cast exception. However, when calling myObject.toString you get a logical representation in String format of that object and it depends on implementation …

Casting object to String[] object.

Assume the following scenario. i call a method like this

and the method signature is

public void method(Object o) < // how will i get back the String[] arr object now.. >

The casting would look like this:

final String[] array = (String[]) o; 

public void method(Object o)

this means the only valid parameter type is String[] and you are better off making this clear with

public void method(String[] arr)

public void method(Object o)

Here o is your passed String[] object. Just cast it to String[] . And if you are planning to pass an array every time then change your method signature to:

public void method(Object[] o) 

Java — Convert String into a Class Object, I am storing a class object into a string using toString() method. Now, I want to convert the string into that class object. First, if I’m understanding your question, you want to store your object into a String and then later to be able to read it again and re-create the Object. Personally, when I need to do that I use …

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Casting an object to string in java

Java Object to String Example: Converting StringBuilder

Let’s see the simple code to convert StringBuilder object to String in java.

String is: hello Reverse String is: olleh

Now you can write the code to check the palindrome string.

So, you can convert any Object to String in java using toString() or String.valueOf(object) methods.

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Convert Object to String in Java

In Java, you can convert an object to a string using the toString() method, which is a method of the Object class. This method returns a string that represents the object.

We can also use the String.valueOf() method to convert an object to a string in Java. This method is a static method of the String class that takes an object as a parameter and returns a string that represents the object.

Introduction

The Object class is the superclass of all other classes in Java. It implies that a reference variable of Object type can refer to an instance of any other class. Every class in Java inherits methods of the Object class implicitly.

In Java, you can convert an object to a string using the toString() method, which is a method of the Object class. Similarly, there are other methods in the Object class that can be used for converting an instance to a string as listed below.

Methods	Description	Time Complexity
String toString()	Returns the string representation that describes the object.	O(n)
String valueOf()	This method belongs to a String class and is a static method.	O(n)
+ operator	It is used for concatenating any type of value with a string and returns the output as a string.	O(1)
join()	It allows you to an array of objects into a single string. This method is part of the String class and it takes two parameters: a delimiter and an array of objects.	O(n*k)

Java Program to Convert Object of a User-Defined Class to String Using toString() Method

In this example, we will learn how to convert an object into a string using toString() method.

Explanation:

• The code above defines a class EmployeeTest that has two instance variables firstName and lastName , along with getter and setter methods to access and modify these variables.
• The class also overrides the toString() method to provide a customized string representation of the EmployeeTest object.
• The main() method creates an EmployeeTest object and calls its getString() method to print its string representation as shown.

Java Program to Convert Object of Predefined Class(StringBuilder) to String Using valueOf() Method

In this example, we will learn how to convert an object to a string using the valueOf method.

Explanation:

• In this code, the main() method creates an EmployeeTest object and calls the String.valueOf() method to print its string representation as shown.

Java Program to Convert Object to String Using the + Operator in Java

Write a program to covert the object to string using the ‘+’ concatenation operator

Explanation:

• In this code, the main() method creates an EmployeeTest object and uses the concatenation (+) operator method to print its string representation as shown.

Java Program to Convert Object to String Using the join() Method in Java

The join() method of the String class can be used to concatenate the string representations of the objects in an array as shown below.

Explanation:

• This code creates a list of strings list and adds three string elements to it.
• The join() method of the String class is used to concatenate the elements of the list into a single string with a comma separator.
• The resulting string is then printed to the console using the System.out.println() method.

Conclusion

• Java provides several methods for converting an object to a string, including the toString() method, String.valueOf() method, + operator, and join() method.
• The toString() and String.valueOf() methods are part of the Object and String classes, respectively, and they return a string that represents the object.
• The + operator is used for concatenating any type of value with a string and returns the output as a string.
• Finally, the join() method allows you to join an array of objects into a single string.
• When converting an object to a string, it is essential to consider the time complexity of the method used. The + operator has a time complexity of O(1) , while the join() method has a time complexity of O(n*k) .

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