详解Java String类常用方法有哪些

package com.llg.learnString;


import java.util.Arrays;
import java.util.Locale;

public class Learn01 {
    //程序的入口
    public static void main(String[] args) {
        String s11 = "abcdefghijk";
        System.out.println(s11);
        //字符串截取 从第3位开始取到最后
        System.out.println(s11.substring(3));//defghijk
        //字符串截取 从第3位开始取到第6位最后
        System.out.println(s11.substring(3, 6));//def
        //字符串合并拼接 把zzzzz拼接到后面
        System.out.println(s11.concat("zzzzz"));//abcdefghijkzzzzz
        //字符串中的字符替换 把b替换为x
        System.out.println(s11.replace('b','x'));//axcdefghijk

        String s12 = "a-b-c-def-ghi-jk";
        //字符串分割 以-分割字符串，返回字符串数组
        String[] strarr= s12.split("-");
        System.out.println(Arrays.toString(strarr));//[a, b, c, def, ghi, jk]

        //转换为小写
        String s13 = "abc";
        System.out.println(s13.toUpperCase());//ABC
        //转换为大写
        String s14 = "ABC";
        System.out.println(s14.toLowerCase());//abc
        //去除首尾空格
        String s15 = "  a b c def ";
        System.out.println(s15.trim());//a b c def

        //toString
        String s16 = "abc";
        System.out.println(s16.toString());//abc

        //转换为字符串String.valueOf
        System.out.println(String.valueOf(true));//true
        System.out.println(String.valueOf(false));//false
    }
}