Interview Question 35: The first character that appears only once

Package com.abuge;

/** * Face Test 35: The first occurrence of the character * title: In the string to find the first occurrence of only one character, such as the input "Abaccdeff", then output ' B '/import java.util.HashMap;
		public class Getfirstoncechar {public static char getfirstonce (String str) {if (str = null) return ' 0 ';
		hashmap<string, integer> HashMap = new hashmap<string, integer> ();
		
		
		int len = Str.length ();
			Iterates through the string, counting the number of occurrences of each character in the string for (int i = 0; i < len; i++) {String tmpstr = "" + Str.charat (i);
				if (Hashmap.containskey (TMPSTR)) {int value = Hashmap.get (TMPSTR);
				value++;
				
				Hashmap.remove (TMPSTR);
			Hashmap.put (tmpstr, value);
			}else {hashmap.put (tmpstr, 1);
			}//Iterate through the string again to find the character for (int i = 0; i < len; i++) {String tmpstr = "" + Str.charat (i);
			
			int value = Hashmap.get (TMPSTR);
				if (value = = 1) {System.out.println (Str.charat (i));
			return Str.charat (i);
	} return ' 0 ';
///Custom hash table public static char getfirstonce_2 (String str) {if (str = null)		{return ' 0 ';
		//Only consider ASCII code, so there are 256 characters int[] hashTable = new int[256];
		int len = Str.length ();
			
			Traversal string for (int i = 0; i < len; i++) {char c = str.charat (i);
		hashtable[c]++;
			
			///Traversal string find the first occurrence of the character for (int i = 0; i < len; i++) {char c = str.charat (i);
				if (hashtable[c] = = 1) {System.out.println (c);
			return C;
	} return ' 0 ';
		public static void Main (string[] args) {System.out.println ("single character:");
		Getfirstonce ("a");
		
		Getfirstonce_2 ("a");
		System.out.println ("No single character exists:");
		
		Getfirstonce_2 ("Bbccddee");
		System.out.println ("All is a single string:");
		Getfirstonce ("Bacde");
		
		Getfirstonce_2 ("Bacde");
		System.out.println ("There is a character normal string that appears once:");
		Getfirstonce ("Abaccdeff");
		
		Getfirstonce_2 ("Abaccdeff");
		SYSTEM.OUT.PRINTLN ("null:");
		Getfirstonce (NULL);
		
	Getfirstonce_2 (NULL);
 }

}