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String字串類等

package com.javasm.demo;
import java.util.Arrays;
import java.util.Date;
/**
 * @Author:liulei
 * @Version:1.0
 * @Date:2022/11/29-15:54
 * @Since:jdk1.8
 * @Description:
 */
public class StringDemo2 {
    public static void main(String[] args) {
        String string1 = "Aello你好123123";
        String string2 
= "Cello123"; //比較 System.out.println(string1.compareTo(string2));// 比較A-C-->-2 System.out.println("是否以h開頭:" + string1.startsWith("h"));//false System.out.println("是否以h結尾:" + string1.endsWith("h"));//false //字串搜尋:索引位置 System.out.println("查詢索引位置:" + string1.indexOf("A"));//
0 System.out.println("查詢索引位置,開始查詢的位置:" + string1.indexOf("A", 1));//-1 System.out.println("傳遞ascll值,查詢對應的索引位置:" + string1.indexOf(49));//7 System.out.println("傳遞ascll值,查詢對應的索引位置:" + string1.indexOf(49, 6));//7 System.out.println("查詢最後一個索引位置:" + string1.lastIndexOf("a"));//-1
//提取字串 System.out.println("提取索引1位置的字元:" + string1.charAt(1));//e //從5擷取到最後 System.out.println("擷取字串:" + string1.substring(7));//從索引7開始-->123123 //擷取,不包含結束索引!!! System.out.println("擷取字串,起始索引和結束索引:" + string1.substring(5, 7));//索引5-7-->你好 //拼接字串 string1 = string1.concat("社發斯蒂芬"); string1 = string1.concat(new Date().toString()); System.out.println(string1);//Aello你好123123社發斯蒂芬Tue Nov 29 19:13:48 CST 2022 //替換 string1 = string1.replace('e', 'E'); System.out.println(string1);//AEllo你好123123社發斯蒂芬TuE Nov 29 19:13:48 CST 2022 //替換字串 string1 = string1.replaceAll("123", "321"); System.out.println(string1);//AEllo你好321321社發斯蒂芬TuE Nov 29 19:14:29 CST 2022 //去空格 String string = " 123 456 789 "; System.out.println(string);// 123 456 789 System.out.println(string.trim()); //123 456 789去頭尾的空格 //將所有的空格替換 string = string.replaceAll(" ", ""); System.out.println(string);//123456789 //分割字串 string = "123,456,789,abc"; String[] split = string.split(","); System.out.println(Arrays.toString(split));//[123, 456, 789, abc] System.out.println(split.length);//4 //判斷是否包含? System.out.println("是否包含:" + string.contains("123"));//true String isContinue = "Y"; if (isContinue.toLowerCase().equals("y")) { System.out.println("OK!"); }//輸y和Y都可以輸出OK /* 通過string+byte實現編碼格式的轉換! getBytes:將字串轉成byte陣列! */ String string3 = "hello你哈"; System.out.println(Arrays.toString(string3.getBytes())); //[104, 101, 108, 108, 111, -28, -67, -96, -27, -109, -120] /* 將字串轉成字元陣列! char [] */ char[] chars = string3.toCharArray(); System.out.println(Arrays.toString(chars));//[h, e, l, l, o, 你, 哈] /* 將“123”轉成 123! */ String string4 = "123"; char[] chars1 = string4.toCharArray(); for (int c : chars1) { System.out.println(c - 48); } } }