Java determines whether a string contains a certain character (string)

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

1. startsWith()

This method has two variants and tests If a string starts at the specified index the specified prefix or by default starts at the string position

The syntax defined for this method is as follows:

public boolean startsWith(String prefix, int toffset)
or
public boolean startsWith(String prefix)

prefix – The prefix to match. Here are the details of the parameters:

toffset – where to start looking for the string.

The return value is true and false

import java.io.*;
 
public class Test{
   public static void main(String args[]){
      String Str = new String("Welcome to Yiibai.com");
 
      System.out.print("Return Value :" );
      System.out.println(Str.startsWith("Welcome") );
 
      System.out.print("Return Value :" );
      System.out.println(Str.startsWith("Tutorials") );
 
      System.out.print("Return Value :" );
      System.out.println(Str.startsWith("Yiibai", 11) );
   }
}

2. contains method

java.lang.String.contains()

The method returns true when and Only if this string contains the specified char value sequence

The return value is true and false

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");
        }
 
    }

3, indexOf method

java.lang.String.indexOf() The purpose is to find the position of a word in a string, and at the same time, it can also determine whether a string contains a certain character.

The return value of indexOf is int

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

For more java knowledge, please Follow java basic tutorial.

The above is the detailed content of Java determines whether a string contains a certain character (string). For more information, please follow other related articles on the PHP Chinese website!