Java method to determine whether a string contains specified characters

Java method to determine whether a string contains specified characters:

1. Use the contains method to determine

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

Statement: public boolean contains(CharSequence s)

Return value: This method returns true if this string contains, otherwise it returns false.

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. Use the indexOf method to determine whether the purpose of

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

Statement: int indexOf(int ch,int fromIndex)

Return value: The return value of indexOf is int

Example:

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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