JavaでのStringクラスの一般的な使い方

Stringクラスの基本的な使い方:

public class String       {
     
	public static void main(String arg[]){
     
		System.out.println("------     ---------");
		String s01 = new String("hello");

		System.out.println("------          ---------");
		byte[] byteArray = {
     97,98,99};
		String s02 = new String(byteArray);
		System.out.println(s02);

		System.out.println("------          ---------");
		char[] charArray1 = {
     'a','b','c'};
		String s03 = new String(charArray1);
		System.out.println(s03);

		System.out.println("------                 ---------");
		char[] charArray2 = {
     'a','b','c','d','e'};
		//charArray2   2       ，1     
		String s04 = new String(charArray2,2,1);
		System.out.println(s04);

		System.out.println("------length       ---------");
		String s = "abc";
		System.out.println(s.length());   //3

		System.out.println("------         ---------");
		char[] arr=s03.toCharArray();
		System.out.println(arr);
		for(char ch:arr) {
     
			System.out.println(ch);
		}

		System.out.println("------         ---------");
		byte[] bytes = s02.getBytes();
		for(byte b:bytes) {
     
			System.out.println(b);
		}

		//     
		String s05 = "hello";
		String upperCase = s05.toUpperCase();
		//     
		String s06 = "ABC";
		String lowerCase = s06.toLowerCase();

		System.out.println("------            "+"---------");
		int age= 6;
		String s6="He is" + age + "years old.";
		//s        
		System.out.println(s6);

		System.out.println("------trim  ---------");
		//trim （  ）
		String s7 = "   xs  ";
		String newString = s7.trim();

		System.out.println("------  ---------");
		String s07 = "asd";
		String s08 = "ASD"; 
		//           
		System.out.println(s07.equals(s08));  //false
		//           (     )
		System.out.println(s07.equalsIgnoreCase(s08));  //true
		String s09 = "abcdef";
		String s10 = "abc";
		//     s09   s10  
		System.out.println(s09.startsWith(s10));  //true
		//     s09   s10  
		System.out.println(s09.endsWith(s10));  //false
		//     s11    
		String s11 = " ";
		System.out.println(s11.isEmpty());  //false

		System.out.println("------  ---------");
		String s15 = "asdfghj";
		//         
		char ch = s15.charAt(2);  //d
		String s16 = "zxcvxbnxm";
		//                   ，         -1
		int index = s16.indexOf('v');   //3
		index = s16.indexOf(2);   // -1
		//                    ，         -1
		index = s16.lastIndexOf('x');  //7
		index = s16.lastIndexOf(3);  //-1

		System.out.println("------         ---------");
		String s18 = "zabjkl";
		String reS18 = s18.replace('a','v');
		System.out.println(reS18);  // zvbjkl
		String s19 = "    ";
		String reS19 = s19.replace("  ", "  ");
		System.out.println(reS19);  //     

		System.out.println("------  ---------");
		String s20 = "       ";
		//    4         
		s20.substring(4);  //   
		//    2         ，  3  
		s20.substring(2, 4); //  

		System.out.println("------  ---------");
		//            
		//           ，  0
		//                ，    0  
		//                ，    0  
		String s21 = "abd";
		String s22 = new String("abc");
		int result = s21.compareTo(s22);
		System.out.println(result);

		System.out.println("------            ，     ---------");
		result = s21.compareToIgnoreCase(s22);
		System.out.println(result);

		System.out.println("------  ---------");
		String s23 = "asd-dfg-gjh-jkl";
		//              
		//          
		String[] splitArray = s23.split("-");
		for(String str:splitArray) {
     
			System.out.println(str);
		}

		System.out.println("------          ---------");
		//             ，           
		char[] chs = {
     'a','c','n'};
		System.out.println(String.valueOf(chs));
		
		System.out.println("-------Java split       -------");
         String str="good good study, day day up";
	     String[] strarray=str.split(" ");
	     for (int i = 0; i < strarray.length; i++)
	          System.out.println(strarray[i]);
		}

	
}