What are the methods in Java to determine whether a string contains a specific string?

N ways to determine whether a string contains a certain substring:

1, startsWith()method

2. contains()method

3.indexOfmethod

startsWith() method

There are two variants of this method that detect whether a string starts with a specified prefix.

The syntax defined by this method is as follows:

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

Parameter description:

prefix – The prefix to be matched.

toffset – Where to start looking for the string.

Return value:

true and false

Related video tutorial recommendation: java learning video

Example:

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) );
   }
}

contains method

java.lang.String.contains()

method returns true if and only if this string contains the specified sequence of char values.

Return value:

true and false

Examples are as follows:

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");
        }
 
    }

indexOf method

java.lang.String.indexOf()

The purpose is to find the position of a word in a string, and also to determine whether a string contains a certain character.

Return value:

int

The example is as follows:

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 related tutorials, please visit: java introductory learning

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