这几个常用的工具类，让你生产力爆表！

import cn.hutool.core.util.StrUtil;
public class StrUtilExample {
    public static void main(String[] args) {
        // 判断字符串是否为空
        String str = "";
        boolean isEmpty = StrUtil.isEmpty(str);
        System.out.println(isEmpty); // 输出：true
        // 字符串拼接
        String[] strs = {"Hello", "Hutool"};
        String result = StrUtil.join("-", strs);
        System.out.println(result); // 输出：Hello-Hutool
        // 字符串截取
        String str = "Hello, World!";
        String result = StrUtil.sub(str, 7, 12);
        System.out.println(result); // 输出：World
        // 字符串格式化
        String name = "Alice";
        int age = 25;
        String result = StrUtil.format("My name is {}, and I'm {} years old.", name, age);
        System.out.println(result); // 输出：My name is Alice, and I'm 25 years old.
    }
}

import cn.hutool.core.date.DateUtil;
public class DateUtilExample {
    public static void main(String[] args) {
        // 获取当前日期
        Date now = DateUtil.date();
        System.out.println(now); // 输出：2023-01-01 10:30:00
        // 日期格式化
        String dateStr = "2023-01-01";
        Date date = DateUtil.parse(dateStr);
        String formattedDate = DateUtil.format(date, "yyyy/MM/dd");
        System.out.println(formattedDate); // 输出：2023/01/01
        // 日期加减
        Date date = DateUtil.date(); // 2023-01-01 10:30:00
        Date nextWeek = DateUtil.offsetWeek(date, 1);
        System.out.println(nextWeek); // 输出：2023-01-08 10:30:00
        // 日期比较
        Date date1 = DateUtil.parse("2023-01-01");
        Date date2 = DateUtil.parse("2023-02-01");
        boolean isBefore = DateUtil.isBefore(date1, date2);
        System.out.println(isBefore); // 输出：true
    }
}

import cn.hutool.core.util.UrlUtil;
public class UrlUtilExample {
    public static void main(String[] args) {
        // URL编码
        String url = "https://www.example.com/search?keyword=Java";
        String encodedUrl = UrlUtil.encode(url);
        System.out.println(encodedUrl); // 输出：https%3A%2F%2Fwww.example.com%2Fsearch%3Fkeyword%3DJava
        // URL解码
        String encodedUrl = "https%3A%2F%2Fwww.example.com%2Fsearch%3Fkeyword%3DJava";
        String decodedUrl = UrlUtil.decode(encodedUrl);
        System.out.println(decodedUrl); // 输出：https://www.example.com/search?keyword=Java
        // 拼接URL参数
        String baseUrl = "https://www.example.com/search";
        String keyword = "Java";
        String param = "page=1";
        String fullUrl = UrlUtil.url(baseUrl).param("keyword", keyword).param(param).build();
        System.out.println(fullUrl); // 输出：https://www.example.com/search?keyword=Java&page=1
        // 获取URL中的域名
        String url = "https://www.example.com/search?keyword=Java";
        String domain = UrlUtil.getDomain(url);
        System.out.println(domain); // 输出：www.example.com
    }
}

import cn.hutool.core.io.FileUtil;
public class FileUtilExample {
    public static void main(String[] args) {
        // 读取文件内容
        String content = FileUtil.readUtf8String("path/to/file.txt");
        System.out.println(content);
        // 写入文件内容
        String content = "Hello, Hutool!";
        FileUtil.writeUtf8String(content, "path/to/file.txt");
        // 复制文件
        FileUtil.copy("path/to/source.txt", "path/to/destination.txt", true);
        // 删除文件或目录
        FileUtil.del("path/to/file.txt");
    }
}