package com.example.demo.controller; import com.example.demo.bo.UserBo; import com.example.demo.tool.Gengric; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import java.util.*; @RestController @RequestMapping("/") public class StringController { @GetMapping("/string") public void stringDemo(){ //字符 char charDemo1 = 'x'; Character charDemo2 = new Character('x'); //字符串 String stringDemo1 = "test"; String stringDemo2 = new String("test"); stringDemo2.length(); //获取长度 stringDemo2.concat(" user"); //拼接字符串 stringDemo2.toLowerCase(); //转小写 stringDemo2.compareTo(stringDemo1); //对比 stringDemo2.substring(1,3); //截取 //字符串缓冲区 StringBuffer stringDemo3 = new StringBuffer("test"); stringDemo3.append(" user"); //追加 stringDemo3.insert(2,"u"); //插入 stringDemo3.delete(2,3); //删除 stringDemo3.length(); //获取长度 stringDemo3.substring(0,2); //截取 } @GetMapping("/array") public void arrayDemo(){ //数组,必须指定大小 String[] arrDemo1 = new String[3]; arrDemo1[0] = "str1"; arrDemo1[1] = "str1"; //值可以重复 arrDemo1[2] = "str1"; String[] arrDemo2 = arrDemo1.clone(); //复制 克隆 Arrays.fill(arrDemo2,"test2"); //Array类的使用 UserBo[] arrDemo3 = new UserBo[5]; //对象数组,不是只能用基本类型 } @GetMapping("/arraylist") public void arraylistDemo(){ //泛型可以接收任何参数 Gengric aDemo1 =new Gengric<>(); aDemo1.setDemo1("string"); //不只是基本数据类型 Gengric aDemo2 =new Gengric<>(); UserBo userBo = new UserBo(); aDemo2.setDemo1(userBo); //单向链表 LinkedList aDemo3 = new LinkedList<>(); aDemo3.add("str1"); //插入 aDemo3.get(0); //获取 aDemo3.addFirst("str2"); //头部添加 aDemo3.addLast("str3"); //尾部添加 aDemo3.size(); //长度 //动态数组 ArrayList aDemo4 = new ArrayList<>(); aDemo4.add(userBo); aDemo4.add("str5"); aDemo4.add(100); //可以加入不同数据类型 //HashSet HashSet aDemo5 = new HashSet<>(); aDemo5.add(1); aDemo5.add(2); //TreeSet TreeSet aDemo6 = new TreeSet<>(); aDemo6.add(20); aDemo6.add(10); aDemo6.add(50); //HashMap HashMap aDemo7 = new HashMap<>(); aDemo7.put(5,"str8"); aDemo7.put(1,"str9"); aDemo7.put(3,"str10"); //TreeMap TreeMap aDemo8 = new TreeMap<>(); aDemo8.put(5,"str8"); aDemo8.put(1,"str9"); aDemo8.put(3,"str10"); } }