学习Hutool工具类库

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一、Hutool工具类库介绍

Hutool是一个小而全的Java工具类库，通过静态方法封装，降低相关API的学习成本，提高工作效率，它帮助我们简化每一行代码，避免重复造轮子。如果你有需要用到某些工具方法的时候，可以在Hutool里面找找，可能就有你需要的工具方法。官方地址

Java基础工具类，对文件、流、加密解密、转码、正则、线程、XML等JDK方法进行封装，组成各种Util工具类，同时提供以下组件：

二、引入依赖

        <dependency>
            <groupId>cn.hutoolgroupId>
            <artifactId>hutool-allartifactId>
            <version>5.7.13version>
        dependency>
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三、介绍使用

1、日期时间工具类 DateUtil

    @Test
    void DateUtilTest() {
        //普通创建时间
        Date date = new Date();
        String dateString = "2022-10-18 17:16:57";
        log.info(date.toString());//Thu Oct 27 15:01:56 CST 2022

        //使用DateTime创建时间
        date = DateUtil.date();
        log.info(date.toString());//2022-10-27 15:01:56

        //创建日历
        Calendar instance = Calendar.getInstance();
        log.info(instance.toString());

        //Calendar转Date
        date = DateUtil.date(instance);
        log.info(date.toString());//2022-10-27 15:12:49

        //Calendar转Date
        date = DateUtil.date(System.currentTimeMillis());
        log.info(date.toString());//2022-10-27 15:12:49

        //自动识别格式转换
        date = DateUtil.parse(dateString);
        log.info(date.toString());//2022-10-18 17:16:57

        //自定义格式化转换
        date = DateUtil.parse(dateString, "yyyy-MM-dd");
        log.info(date.toString());//2022-10-18 00:00:00

        //格式化输出日期
        dateString = DateUtil.format(date, "yyyy-MM-dd");
        log.info(dateString);//022-10-18

        //获得年的部分
        Integer year = DateUtil.year(date);
        log.info(year.toString());//2022

        //获得月份，从0开始计数
        Integer month = DateUtil.month(date);
        log.info(month.toString());//9

        //获取某天的开始、结束时间
        Date beginOfDay = DateUtil.beginOfDay(date);
        log.info(beginOfDay.toString());//2022-10-18 00:00:00

        Date endOfDay = DateUtil.endOfDay(date);
        log.info(endOfDay.toString());//2022-10-18 23:59:59

        //计算偏移后的日期时间
        Date newDate = DateUtil.offset(date, DateField.DAY_OF_MONTH, 2);
        log.info(newDate.toString());//2022-10-20 00:00:00

        //计算日期时间之间的偏移量
        Long betweenDay = DateUtil.between(date, newDate, DateUnit.DAY);
        log.info(betweenDay.toString());//2

    }
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2、日期时间对象 DateTime

    @Test
    void DateTimeTest() {
        //普通创建时间
        Date date = new Date();
        //new方式创建
        DateTime time = new DateTime(date);
        log.info(time.toString());//2022-10-28 09:18:41

        //of方式创建
        DateTime now = DateTime.now();
        log.info(now.toString());//2022-10-28 09:18:41
        DateTime dt = DateTime.of(date);
        log.info(dt.toString());//2022-10-28 09:18:41

        //使用对象
        DateTime dateTime = new DateTime("2022年11月11日12时13分14秒", DatePattern.CHINESE_DATE_TIME_FORMAT);//yyyy年MM月dd日HH时mm分ss秒
        log.info(dateTime.toString());//2022-11-11 12:13:14

        //年，结果：2022
        Integer year = dateTime.year();
        log.info(year.toString());
        //月份，结果：Month.NOVEMBER
        Month month = dateTime.monthEnum();
        log.info(month.toString());//NOVEMBER
        //日，结果：11
        Integer day = dateTime.dayOfMonth();
        log.info(day.toString());//11

        //对象的可变性
        DateTime dateTime2 = new DateTime("2022-11-05 12:34:23", DatePattern.NORM_DATETIME_FORMAT);

        //默认情况下DateTime为可变对象，此时offset == dateTime
        DateTime offset = dateTime2.offset(DateField.YEAR, 0);
        log.info(offset.toString());//2022-11-05 12:34:23
        log.info(String.valueOf(offset == dateTime2));//true
        //设置为不可变对象后变动将返回新对象，此时offset != dateTime
        dateTime2.setMutable(false);
        offset = dateTime2.offset(DateField.YEAR, 0);
        log.info(offset.toString());//2022-11-05 12:34:23
        log.info(String.valueOf(offset == dateTime2));//false

    }
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3、类型转换工具类 Convert

    @Test
    void ConvertTest() {
        //转换为字符串
        int a = 1;
        String aStr = Convert.toStr(a);
        log.info(aStr);

        //转换为指定类型数组
        String[] b = {"1", "2", "3", "4"};
        Integer[] bArr = Convert.toIntArray(b);

        ArrayList<String> arrayList = new ArrayList<>();
        arrayList.add("a");
        arrayList.add("b");
        arrayList.add("c");
        String s = Convert.toStr(arrayList);
        log.info(s);//[a, b, c]

        //转换为日期对象
        String dateStr = "2022-11-06";
        Date date = Convert.toDate(dateStr);
        log.info(date.toString());//2022-11-06 00:00:00

        String dateStr2 = "2022年11月06日";
        Date date2 = Convert.toDate(dateStr2);
        log.info(date2.toString());//2022-11-06 00:00:00

        //转换为列表
        String[] strArr = {"1", "2", "3", "4"};
        List<String> stringList = Convert.toList(String.class, strArr);
        log.info(stringList.toString());

        List<Integer> integerList = Convert.toList(Integer.class, strArr);
        log.info(integerList.toString());
    }

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4、字符串工具类 StrUtil

    @Test
    void StrUtilTest() {
        //判断是否为空字符串
        String str = "test";
        log.info(String.valueOf(StrUtil.isEmpty(str)));//false
        log.info(String.valueOf(StrUtil.isNotEmpty(str)));//true
        log.info(String.valueOf(StrUtil.isBlank(str)));//false
        log.info(String.valueOf(StrUtil.isNotBlank(str)));//true

        //isBlank与isEmpty的区别
        String str2 = " ";
        log.info(String.valueOf(StrUtil.isEmpty(str2)));//false
        log.info(String.valueOf(StrUtil.isBlank(str2)));//true

        //去除字符串的前后缀
        String s = StrUtil.removeSuffix("a.jpg", ".jpg");
        log.info(s);//a
        String s1 = StrUtil.removePrefix("a.jpg", "a.");
        log.info(s1);//jpg

        //格式化字符串
        String template = "这只是个占位符:{}";
        String s3 = StrUtil.format(template, "我是占位符12138");
        log.info(s3);//这只是个占位符:我是占位符12138

    }

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5、数字处理工具类 NumberUtil

    @Test
    void NumberUtilTest() {
        Double n1 = 1.234;
        Double n2 = 1.234;
        Double result;

        //对float、double、BigDecimal做加减乘除操作
        result = NumberUtil.add(n1, n2);
        log.info(result.toString());//2.468
        result = NumberUtil.sub(n1, n2);
        log.info(result.toString());//0.0
        result = NumberUtil.mul(n1, n2);
        log.info(result.toString());//1.522756
        result = NumberUtil.div(n1, n2);
        log.info(result.toString());//1.0

        //保留两位小数
        BigDecimal roundNum = NumberUtil.round(n1, 2);
        log.info(roundNum.toString());//1.23

        String n3 = "1.234";
        //判断是否为数字、整数、浮点数
        Boolean number = NumberUtil.isNumber(n3);
        log.info(number.toString());//true
        Boolean integer = NumberUtil.isInteger(n3);
        log.info(integer.toString());//false
        Boolean aDouble = NumberUtil.isDouble(n3);
        log.info(aDouble.toString());//true

    }

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6、JavaBean的工具类 BeanUtil

    @Test
    void JavaBeanTest() {
        People people = new People();
        people.setId(1);
        people.setName("小米");
        people.setJgId(1001);

        //Bean转Map
        Map<String, Object> map = BeanUtil.beanToMap(people);
        log.info(map.toString());//{id=1, name=小米, jgId=1001}

        //Map转Bean
        People mapToBean = BeanUtil.mapToBean(map, People.class, false);
        log.info(mapToBean.toString());//People(id=1, name=小米, jgId=1001)

        //Bean属性拷贝
        People copyPeople = new People();
        BeanUtil.copyProperties(mapToBean, copyPeople);
        log.info(copyPeople.toString());//People(id=1, name=小米, jgId=1001)
    }
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7、集合操作的工具类 CollUtil

    @Test
    void CollUtilTest() {
        //数组转换为列表
        String[] array = new String[]{"a", "b", "c", "d", "e"};
        List<String> list = CollUtil.newArrayList(array);

        //join：数组转字符串时添加连接符号
        String joinStr = CollUtil.join(list, ",");
        log.info(joinStr);

        //将以连接符号分隔的字符串再转换为列表
        List<String> splitList = StrUtil.split(joinStr, ',');
        log.info(splitList.toString());

        //创建新的Set、List
        HashSet<Object> newHashSet = CollUtil.newHashSet();
        ArrayList<Object> newList = CollUtil.newArrayList();

        //判断列表是否为空
        Boolean empty = CollUtil.isEmpty(list);
        log.info(empty.toString());//false
    }
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8、Map操作工具类 MapUtil

        //将多个键值对加入到Map中
        Map<Object, Object> map = MapUtil.of(new String[][]{
                {"key1", "value1"},
                {"key2", "value2"},
                {"key3", "value3"}
        });
        //判断Map是否为空
        Boolean empty = MapUtil.isEmpty(map);
        log.info(empty.toString());//false
        Boolean notEmpty = MapUtil.isNotEmpty(map);
        log.info(notEmpty.toString());//true
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9、数组工具 ArrayUtil

    @Test
    void ArrayUtilTest() {
        //判断空 和 非空
        int[] a = {};
        int[] b = null;
        Boolean empty = ArrayUtil.isEmpty(a);
        log.info(empty.toString());//true
        Boolean empty1 = ArrayUtil.isEmpty(b);
        log.info(empty1.toString());//true

        //判断非空
        int[] a2 = {1, 2};
        Boolean notEmpty = ArrayUtil.isNotEmpty(a2);
        log.info(notEmpty.toString());//true

        //新建泛型数组
        String[] newArray = ArrayUtil.newArray(String.class, 3);
        log.info(newArray.toString());//

        //泛型数组调用原生克隆
        Integer[] b3 = {1, 2, 3};
        Integer[] cloneB = ArrayUtil.clone(b3);
        log.info(Arrays.deepToString(cloneB));//[1, 2, 3]
        
        //非泛型数组（原始类型数组）调用第二种重载方法
        int[] a3 = {1, 2, 3};
        int[] cloneA = ArrayUtil.clone(a3);
        log.info(Arrays.toString(cloneA));//[1, 2, 3]
    }
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10、唯一ID工具 IdUtil

    @Test
    void IdUtilTest() {
        // UUID
        //生成的UUID是带-的字符串，类似于：a5c8a5e8-df2b-4706-bea4-08d0939410e3
        String uuid = IdUtil.randomUUID();
        log.info(uuid);//a9bada65-2298-4daf-a490-861938084ad6

        //生成的是不带-的字符串，类似于：b17f24ff026d40949c85a24f4f375d42
        String simpleUUID = IdUtil.simpleUUID();
        log.info(simpleUUID);//92d6bce683bc45dd8400ce79db18b9a9

        //ObjectId
        //生成类似：5b9e306a4df4f8c54a39fb0c
        String id = ObjectId.next();
        log.info(id);//635b9f20e2d6c9730038d333

        //方法2：从Hutool-4.1.14开始提供
        String id2 = IdUtil.objectId();
        log.info(id2);//635b9f20e2d6c9730038d334

        //Snowflake雪花算法生成数字id
        //参数1为终端ID
        //参数2为数据中心ID
        Snowflake snowflake = IdUtil.getSnowflake(1, 1);
        Long id3 = snowflake.nextId();
        log.info(id3.toString());//1585924733496492032
    }
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11、IO工具类 IoUtil

    @Test
    void IoUtilTest(){
        //文件流拷贝
        BufferedInputStream in = FileUtil.getInputStream("d:/test.txt");
        BufferedOutputStream out = FileUtil.getOutputStream("d:/test2.txt");
        Long copySize = IoUtil.copy(in, out, IoUtil.DEFAULT_BUFFER_SIZE);
        log.info(copySize.toString());//9（字节）
    }
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12、加密解密工具类 SecureUtil

    @Test
    void SecureUtilTest() {
        //MD5加密
        String str = "123456";
        String md5Str = SecureUtil.md5(str);
        log.info(md5Str);//e10adc3949ba59abbe56e057f20f883e
    }
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13、验证码工具类 CaptchaUtil

    @Test
    void CaptchaUtilTest() {
        //生成验证码图片
        LineCaptcha lineCaptcha = CaptchaUtil.createLineCaptcha(200, 100);
        try {
            request.getSession().setAttribute("CAPTCHA_KEY", lineCaptcha.getCode());
            response.setContentType("image/png");//告诉浏览器输出内容为图片
            response.setHeader("Pragma", "No-cache");//禁止浏览器缓存
            response.setHeader("Cache-Control", "no-cache");
            response.setDateHeader("Expire", 0);
            lineCaptcha.write(response.getOutputStream());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
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14、分页工具 PageUtil

    @Test
    void PageUtilTest(){
        //transToStartEnd 将页数和每页条目数转换为开始位置和结束位置。 此方法用于不包括结束位置的分页方法
        int[] startEnd1 = PageUtil.transToStartEnd(0, 10);//[0, 10]
        int[] startEnd2 = PageUtil.transToStartEnd(1, 10);//[10, 20]
        log.info(String.valueOf(startEnd1.length));//2
        log.info(String.valueOf(startEnd2.length));//2

        //根据总数计算总页数
        int totalPage = PageUtil.totalPage(20, 3);//7
        log.info(String.valueOf(totalPage));//7
    }
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15、Java反射工具类 ReflectUtil

    @Test
    void ReflectUtilTest() {
        //获取某个类的所有方法
        Method[] methods = ReflectUtil.getMethods(MyTestUtils.class);
        //获取某个类的指定方法
        Method getIdMethod = ReflectUtil.getMethod(MyTestUtils.class, "getId");
        Method sbMethod = ReflectUtil.getMethod(MyTestUtils.class, "sb");

        //使用反射来创建对象
        MyTestUtils pmsBrand = ReflectUtil.newInstance(MyTestUtils.class);
        //反射执行对象无参的方法
        ReflectUtil.invoke(pmsBrand, "setId", 1L);
        //反射执行对象带参的方法
        try {
            Long invoke = (Long) getIdMethod.invoke(pmsBrand);
            log.info(String.valueOf(invoke));
        } catch (Throwable e) {
            e.printStackTrace();
        }
    }
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16、注解工具类 AnnotationUtil

    @Test
    void AnnotationUtilTest(){
        //获取指定类、方法、字段、构造器上的注解列表
        Annotation[] annotationList = AnnotationUtil.getAnnotations(MyTestUtils.class, false);
        log.info("annotationUtil annotations:{}", annotationList);
        //获取指定类型注解
        Api api = AnnotationUtil.getAnnotation(MyTestUtils.class, Api.class);
        log.info("annotationUtil api value:{}", api.value());//MyTestUtilsApi
        AnnotationUtil.setValue(annotationList[0],"value","sb");
        Api api2 = AnnotationUtil.getAnnotation(MyTestUtils.class, Api.class);
        log.info("annotationUtil api value:{}", api2.value());//sb

        //获取指定类型注解的值
        String annotationValue = AnnotationUtil.getAnnotationValue(MyTestUtils.class, Api.class);
        log.info("annotationUtil api value:{}", annotationValue);//sb
    }
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17、ClassPath资源访问 ClassPathResource

    @Test
    void ClassPathResourceTest(){
        //获取定义在src/main/resources文件夹中的配置文件
        ClassPathResource resource = new ClassPathResource("application-dev.yml");
        Properties properties = new Properties();
        try {
            properties.load(resource.getStream());
        } catch (IOException e) {
            e.printStackTrace();
        }
        log.info("/classPath:{}", properties);
    }
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18、进制工具 HexUtil

    @Test
    void HexUtilTest(){
        // HexUtil主要以encodeHex和decodeHex两个方法为核心，提供一些针对字符串的重载方法
        String str = "我是一个字符串";
        String hex = HexUtil.encodeHexStr(str, CharsetUtil.CHARSET_UTF_8);
        log.info(hex);//e68891e698afe4b880e4b8aae5ad97e7aca6e4b8b2
        String decodedStr = HexUtil.decodeHexStr(hex);
        log.info(decodedStr);//解码后与str相同
    }
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19、URL工具 URLUtil

    @Test
    void URLUtilTest(){
        //获取URL对象
        //        URLUtil.url 通过一个字符串形式的URL地址创建对象
        //        URLUtil.getURL 主要获得ClassPath下资源的URL，方便读取Classpath下的配置文件等信息

        //URLUtil.normalize 标准化化URL链接。对于不带http://头的地址做简单补全
        String url = "http://www.hutool.cn//aaa/bbb";
        String normalize = URLUtil.normalize(url);
        log.info(normalize);//http://www.hutool.cn//aaa/bbb

        url = "http://www.hutool.cn//aaa/\\bbb?a=1&b=2";
        normalize = URLUtil.normalize(url);
        log.info(normalize);//http://www.hutool.cn//aaa//bbb?a=1&b=2
    }
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20、随机工具 RandomUtil

    @Test
    void RandomUtilTest(){
        //例如我们想产生一个[10, 100)的随机数
        int c = RandomUtil.randomInt(10, 100);
        log.info(String.valueOf(c));//61

        // 随机bytes，一般用于密码或者salt生成
        byte[] d = RandomUtil.randomBytes(10);
        log.info(String.valueOf(d));//[B@53747c4a

        //随机获得列表中的一定量的不重复元素，返回Set
        Set<Integer> set = RandomUtil.randomEleSet(CollUtil.newArrayList(1, 2, 3, 4, 5, 6), 2);
        log.info(set.toString());//[2, 1]

        String s = RandomUtil.randomString(2);// 获得两个随机的字符串（只包含数字和字符）
        log.info(s);//jo
        String s1 = RandomUtil.randomNumbers(2);// 获得两个只包含数字的字符串
        log.info(s1);//38

        List<WeightRandom.WeightObj<String>> weightList = new ArrayList<WeightRandom.WeightObj<String>>();
        WeightRandom.WeightObj<String> a1 = new WeightRandom.WeightObj<String>("A", 1);
        WeightRandom.WeightObj<String> b1 = new WeightRandom.WeightObj<String>("B", 2);
        WeightRandom.WeightObj<String> c1 = new WeightRandom.WeightObj<String>("C", 3);
        WeightRandom.WeightObj<String> d1 = new WeightRandom.WeightObj<String>("D", 4);
        weightList.add(a1);
        weightList.add(b1);
        weightList.add(c1);
        weightList.add(d1);

        WeightRandom<String> stringWeightRandom = RandomUtil.weightRandom(weightList);// 权重随机生成器，传入带权重的对象，然后根据权重随机获取对象
        String str = "";
        int num_a = 0, num_b = 0, num_c = 0, num_d = 0;
        for (int i = 0; i < 100000; i++) {
            str = stringWeightRandom.next().toString();
            switch (str) {
                case "A":
                    num_a = num_a+1;
                    break;
                case "B":
                    num_b = num_b+1;
                    break;
                case "C":
                    num_c = num_c+1;
                    break;
                case "D":
                    num_d = num_d+1;
                    break;
            }
        }
        log.info("A---------:{}",num_a);//A---------:10083
        log.info("B---------:{}",num_b);//B---------:19955
        log.info("C---------:{}",num_c);//C---------:30109
        log.info("D---------:{}",num_d);//D---------:39853
    }
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21、身份证工具 IdCardUtil

isValidCard 验证身份证是否合法
convert15To18 身份证15位转18位
getBirthByIdCard 获取生日
getAgeByIdCard 获取年龄
getYearByIdCard 获取生日年
getMonthByIdCard 获取生日月
getDayByIdCard 获取生日天
getGenderByIdCard 获取性别
getProvinceByIdCard 获取省份

    @Test
    void IdCardUtilTest() {
        String ID_18 = "321083197812162119";
        String ID_15 = "150102880730303";

        //是否有效
        boolean valid = IdcardUtil.isValidCard(ID_18);
        log.info(String.valueOf(valid));//true
        boolean valid15 = IdcardUtil.isValidCard(ID_15);
        log.info(String.valueOf(valid15));//true

        //转换
        String convert15To18 = IdcardUtil.convert15To18(ID_15);
        log.info(convert15To18);//150102198807303035

        //年龄
        DateTime date = DateUtil.parse("2000-01-01");
        int age = IdcardUtil.getAgeByIdCard(ID_18, date);
        log.info(String.valueOf(age));//38

        //生日
        String birth = IdcardUtil.getBirthByIdCard(ID_18);
        log.info(birth);//19781216

        //性别
        int genderByIdCard = IdcardUtil.getGenderByIdCard(ID_18);
        log.info(String.valueOf(genderByIdCard));//奇数为男，偶数为女

        //省份
        String province = IdcardUtil.getProvinceByIdCard(ID_18);
        log.info(province);//江苏

    }

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22、信息脱敏工具 DesensitizedUtil

    @Test
    void DesensitizedUtilTest() {

        String s1 = DesensitizedUtil.idCardNum("51343620000320711X", 1, 2);
        log.info(s1);       // 5***************1X


        String s2 = DesensitizedUtil.mobilePhone("18049531999");
        log.info(s2);        // 180****1999

        String s3 = DesensitizedUtil.password("1234567890");
        log.info(s3);        // 比如密码，只保留了位数信息,**********
    }
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