# Java 程序：查找字符串中字符的出現 > 原文： [https://beginnersbook.com/2019/04/java-program-to-find-the-occurrence-of-a-character-in-a-string/](https://beginnersbook.com/2019/04/java-program-to-find-the-occurrence-of-a-character-in-a-string/) 在本教程中，我們將編寫一個 Java 程序來查找`String`中字符的出現。 ## 編程以查找字符串中字符的出現 在這個程序中，我們發現`String`中每個字符的出現。為此，我們首先創建一個大小為 256（ASCII 上限）的數組，這里的想法是將出現次數存儲在該字符的 ASCII 值中。例如，`'A'`的出現將存儲在計數器[65]中，因為`A`的 ASCII 值是 65，類似地，其他字符的出現存儲在它們的 ASCII 索引值中。 然后我們創建另一個數組`array`來保存給定`String`的字符，然后我們將它們與`String`中的字符進行比較，當找到匹配時，使用`counter`數組顯示該特定字符的計數。 ```java class JavaExample { static void countEachChar(String str) { //ASCII values ranges upto 256 int counter[] = new int[256]; //String length int len = str.length(); /* This array holds the occurrence of each char, For example * ASCII value of A is 65 so if A is found twice then * counter[65] would have the value 2, here 65 is the ASCII value * of A */ for (int i = 0; i < len; i++) counter[str.charAt(i)]++; // We are creating another array with the size of String char array[] = new char[str.length()]; for (int i = 0; i < len; i++) { array[i] = str.charAt(i); int flag = 0; for (int j = 0; j <= i; j++) { /* If a char is found in String then set the flag * so that we can print the occurrence */ if (str.charAt(i) == array[j]) flag++; } if (flag == 1) System.out.println("Occurrence of char " + str.charAt(i) + " in the String is:" + counter[str.charAt(i)]); } } public static void main(String[] args) { String str = "beginnersbook"; countEachChar(str); } } ``` **輸出：**  #### 相關的 Java 程序 1. [Java 程序：按字母順序排序字符串](https://beginnersbook.com/2018/10/java-program-to-sort-strings-in-an-alphabetical-order/) 2. [Java 程序：檢查元音和輔音](https://beginnersbook.com/2017/09/java-program-to-check-vowel-and-consonant-using-switch-case/) 3. [Java 程序：查找字符串中的重復字符](https://beginnersbook.com/2014/07/java-program-to-find-duplicate-characters-in-a-string/) 4. [Java 程序：檢查回文串](https://beginnersbook.com/2014/01/java-program-to-check-palindrome-string-using-recursion/)