How to convert String into Hashmap in java

Question

How can I convert a String into a HashMap   String value     first name   naresh  last name   kumar  gender   male     into  Map lt Object  Object gt          first name   naresh      last name   kumar      gender   male     Where the keys are first name  last name and gender and the values are naresh  kumar  male   Note  Keys can be any thing like city   hyderabad   I am looking for a generic approach

User · Answer

You can do it in single line  for any object type not just Map   Since I use Gson quite liberally  I am sharing a Gson based approach  Gson gson   new Gson        Map lt Object Object gt  attributes   gson fromJson gson toJson value  Map class    What it does is   gson toJson value  will serialize your object into its equivalent Json representation   gson fromJson will convert the Json string to specified object   in this example - Map   There are 2 advantages with this approach   The flexibility to pass an Object instead of String to  toJson method  You can use this single line to convert to any object even your own declared objects

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Should Use this way to convert into map       String student     students split  quot       quot        String id name     student 1  split  quot   quot         Map lt String String gt  studentIdName   new HashMap lt  gt          for  String std  id name            String str     std split  quot   quot            studentIdName put str 0  str 1

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String value     first name   naresh last name   kumar gender   male     Let s start    Remove   and   from the String  first name   naresh last name   kumar gender   male Split the String from     array of 3 element Now you have an array with 3 element Iterate the array and split each element by   Create a Map lt String String gt  put each part separated by    first part as Key and second part as Value

User · Answer

try this out     public static HashMap HashMapFrom String s       HashMap base   new HashMap      result     int dismiss   0    dismiss tracker     StringBuilder tmpVal   new StringBuilder      each val holder     StringBuilder tmpKey   new StringBuilder      each key holder      for  String next s split         each of vale         if dismiss  0     if not writing value             if  next equals         start writing value                 dismiss 1    update tracker             else                 tmpKey append next     writing key           else               if  next equals         if it s value so need to dismiss                 dismiss                else if  next equals         value closed so need to focus                 dismiss--              else if  next equals        declaration ends                      amp  amp  dismiss  1                      by the way you have to create something to correct the type                 Object ObjVal   object valueOf tmpVal toString       correct the type of object                 base put tmpKey toString   ObjVal    declaring                 tmpKey   new StringBuilder                    tmpVal   new StringBuilder                    dismiss--                  continue    next                              tmpVal append next     writing value                     Object objVal   object valueOf tmpVal toString       same as here     base put tmpKey toString    objVal     leftovers     return base      examples input    a 0 b  a 1  c  ew  qw 2   0 a  output    0 a a 0 b  a 1  c  ew  qw 2

User · Answer

This is one solution  If you want to make it more generic  you can use the StringUtils library  String value    quot  first name   naresh last name   kumar gender   male  quot   value   value substring 1  value length  -1               remove curly brackets String   keyValuePairs   value split  quot   quot                   split the string to creat key-value pairs Map lt String String gt  map   new HashMap lt  gt                     for String pair   keyValuePairs                           iterate over the pairs       String   entry   pair split  quot   quot                        split the pairs to get key and value      map put entry 0  trim    entry 1  trim                add them to the hashmap and trim whitespaces    For example you can switch  value   value substring 1  value length  -1    to  value   StringUtils substringBetween value   quot   quot    quot   quot     if you are using StringUtils which is contained in apache commons lang package

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Test public void testToStringToMap         Map lt String String gt  expected   new HashMap lt  gt         expected put  first name    naresh        expected put  last name    kumar        expected put  gender    male        String mapString   expected toString        Map lt String  String gt  actual   Arrays stream mapString replace          replace          split                    map arrayData- gt  arrayData split                    collect Collectors toMap d- gt    String d 0   trim    d- gt   String d 1          expected entrySet   stream   forEach e- gt assertTrue actual get e getKey    equals e getValue

[java] How to convert String into Hashmap in java

You can do it in single line, for any object type not just Map.

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