How to convert String to BigInteger representation and back in Java? -

let's suppose have string, let's call foo. string can contain value, letters, numbers, special characters, utf-8 special characters, such á , on. instance, might real value:

"Érdekes szöveget írtam tegnap, 84 ember olvasta." 

i have following 2 methods:

public biginteger tobiginteger(string foo) {     //returns biginteger value can associated foo }  public string frombiginteger(biginteger bar) {     //returns string value can associated bar } 

then:

string foo = "Érdekes szöveget írtam tegnap, 84 ember olvasta."; system.out.println(frombiginteger(tobiginteger(foo))); //output should be: "Érdekes szöveget írtam tegnap, 84 ember olvasta." 

how can achieve this? thanks

the following code expect:

public biginteger tobiginteger(string foo) {     return new biginteger(foo.getbytes()); }  public string frombiginteger(biginteger bar) {     return new string(bar.tobytearray()); } 

however don't understand why need , interested of explanation.