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How to determine whether a string contains a certain character in java

Java method to determine whether a string contains a certain character:

1. contains method

1: Description

java The .lang.String.contains() method returns true if and only if this string contains the specified char value sequence

2: Statement

public boolean contains(CharSequence s)

3: Return value

If this string contains, return true, otherwise return false.

4: Example

public static void main(String[] args) {
    String str = "abc";
       boolean status = str.contains("a");
       if(status){
           System.out.println("包含");
       }else{
           System.out.println("不包含");
       }
}

2. indexOf method

1: Description

The purpose of java.lang.String.indexOf() is to Find the position of a word in a string, and also determine whether a string contains a certain character.

2: Statement

int indexOf(int ch,int fromIndex)

3: Return value

The return value of indexOf is int

4: Instance

public static void main(String[] args) {
    String str1 = "abcdefg";
       int result1 = str1.indexOf("a");
       if(result1 != -1){
           System.out.println("字符串str中包含子串“a”"+result1);
       }else{
           System.out.println("字符串str中不包含子串“a”"+result1);
       }
}

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