Convert String into a Class Object

Question

I am storing a class object into a string using toString   method  Now  I want to convert the string into that class object   How to do that  Please help me with source code

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You cannot store a class object into a string using toString    toString   only returns a String representation of your object-in any way you d like  You might want to do some reading about Serialization

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I am storing a class object into a string using toString   method  Now  I want to convert the string into that class object    Your question is ambiguous   It could mean at least two different things  one of which is     well     a serious misconception on your part     If you did this   SomeClass object       String s   object toString      then the answer is that there is no simple way to turn s back into an instance of SomeClass   You couldn t do it even if the toString   method gave you one of those funky  SomeClass xxxxxxxx  strings    That string does not encode the state of the object  or even a reference to the object   The xxxxxxxx part is the object s identity hashcode   It is not unique  and cannot be magically turned back into a reference to the object    The only way you could turn the output of toString back into an object would be to    code the SomeClass toString   method so that included all relevant state for the object in the String it produced  and code a constructor or factory method that explicitly parsed a String in the format produced by the toString   method    This is probably a bad approach   Certainly  it is a lot of work to do this for non-trivial classes     If you did something like this   SomeClass object       Class c   object getClass    String cn   c toString      then you could get the same Class object back  i e  the one that is in c  as follows   Class c2   Class forName cn     This gives you the Class but there is no magic way to reconstruct the original instance using it    Obviously  the name of the class does not contain the state of the object      If you are looking for a way to serialize   deserialize an arbitrary object without going to the effort of coding the unparse   parse methods yourself  then you shouldn t be using toString   method at all   Here are some alternatives that you can use    The Java Object Serialization APIs as described in the links in  Nishant s answer  JSON serialization as described in  fatnjazzy s answer  An XML serialization library like XStream  An ORM mapping    Each of these approaches has advantages and disadvantages     which I won t go into here

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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 ObjectOutputStream  However  there is a mandatory condition  The object you want to convert to a String and then back to an Object must be a Serializable object  and also all its attributes   Let s Consider ReadWriteObject  the object to manipulate and ReadWriteTest the manipulator   Here is how I would do it   public class ReadWriteObject implements Serializable            Serial Version UID        private static final long serialVersionUID   8008750006656191706L       private int age      private String firstName      private String lastName                   param age         param firstName         param lastName             public ReadWriteObject int age  String firstName  String lastName            super            this age   age          this firstName   firstName          this lastName   lastName                        non-Javadoc                  see java lang Object toString                Override     public String toString             return  ReadWriteObject  age     age      firstName     firstName      lastName     lastName                   public class ReadWriteTest        public static void main String   args  throws IOException  ClassNotFoundException              Create Object to write and then to read            This object must be Serializable  and all its subobjects as well         ReadWriteObject inputObject   new ReadWriteObject 18   John    Doe                Read Write Object test             Write Object into a Byte Array         ByteArrayOutputStream baos   new ByteArrayOutputStream 1024           ObjectOutputStream oos   new ObjectOutputStream baos           oos writeObject inputObject           byte   rawData   baos toByteArray            String rawString   new String rawData           System out println rawString               Read Object from the Byte Array         byte   byteArrayFromString   rawString getBytes            ByteArrayInputStream bais   new ByteArrayInputStream byteArrayFromString           ObjectInputStream ois   new ObjectInputStream bais           Object outputObject   ois readObject            System out println outputObject             The Standard Output is similar to that  actually  I can t copy paste it           sr   com ajoumady stackoverflow ReadWriteObjecto         L    I  ageL  firstNamet  Ljava lang String L  lastNameq    xp  t  John  Doe  ReadWriteObject  age 18  firstName John  lastName Doe

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Class forName nameString  newInstance

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As stated by others  your question is ambiguous at best  The problem is  you want to represent the object as a string  and then be able to construct the object again from that string    However  note that while many object types in Java have string representations  this does not guarantee that an object can be constructed from its string representation   To quote this source      Object serialization is the process of saving an object s state to a sequence of bytes  as well as the process of rebuilding those bytes into a live object at some future time     So  you see  what you want might not be possible  But it is possible to save your object s state to a byte sequence  and then reconstruct it from that byte sequence

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Much easier way of doing it  you will need com google gson Gson for converting the object to json string for streaming  to convert object to json string for streaming use below code  Gson gson   new Gson    String jsonString   gson toJson MyObject     To convert back the json string to object use below code   Gson gson   new Gson    MyObject   gson fromJson decodedString   MyObjectClass class     Much easier way to convert object for streaming and read on the other side  Hope this helps  - Vishesh

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Continuing from my comment  toString is not the solution  Some good soul has written whole code for serialization and deserialization of an object in Java  See here  http   www javabeginner com uncategorized java-serialization  Suggested read    Old and good Java Technical Article on Serialization http   java sun com developer technicalArticles ALT serialization  http   java sun com developer onlineTraining Programming BasicJava2 serial html

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You can use the statement  -  Class c   s getClass      To get the class instance

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You might want to do it with json  Convert your bean    to json an then back  this proccess is known as serialisation and deserialisation read about it here      Dont use just members as the data source  build getters and setters for each member in your object

[java] Convert String into a Class Object

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