Java implementation capitalize the first letter of each word in a sentence of

Write a Java program, the sentence entered by the user among the first letter of each word capitalized, while the rest of the word in lowercase letters.
Requirements: Running the program requires the user to enter a sentence. Then extract each word, the first letter of a word to uppercase and the rest lowercase characters. Use StringBuffer class to create a new string to replace over-sensitive. New final output string.
Hint: Use the Scanner nextLine () method to obtain a sentence. Note: the word delimiter spaces addition, there may or Tab (,; punctuation.). Note judge first character is not a letter. Other letters in a word may be capitalized.
For example: when the user inputs "This is a samPLe sentencE to demostrATE the TasK 2."
program should Output: This Is A Sample Sentence To Demonstrate The Task 2.

code show as below

package CaseSubstitution;

import java.util.Scanner;
/**
 * 
 * @author 芳芳
 *
 */
public class CaseSubstitution {
	public static void main(String[] args) {
		@SuppressWarnings("resource")
		Scanner input = new Scanner(System.in);
		System.out.println("please input a string:");
	    String s = input.nextLine();
	    System.out.println("converted result is as follows:");
	    si(s);
	}
	private static void si(String s) {
	    String[] split = s.split(" ");
	    //按空格分隔成数组
	    for (int i = 0; i <split.length ; i++) {
	    // .substring(0,1) 截取数组的首字母   +split[i].substring(1); 再加上后面
	        String s2 = split[i].substring(0, 1).toUpperCase()+split[i].substring(1);
	        System.out.print(s2+" ");
	    }
	}
}