Java工具类之Apache的Commons Lang和BeanUtils
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2022-05-01 17:41:37
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Apache Commons包估计是Java中使用最广发的工具包了,很多框架都依赖于这组工具包中的一部分,它提供了我们常用的一些编程需要,但是JDK没能提供的机能,最大化的减少重复代码的编写。
http://commons.apache.org/
1)Commons Lang是对JDK中java.lang包的补充,提供了各种各样的Utilities工具类,这里说说最常用的几个工具类。
版本:commons-lang3-3.1.jar
1、字符串的空判断
2、字符串的Trim
3、字符串的分割
4、字符串的连接
5、字符串的Escape
6、随机数
7、数组
8、日期
2)Commons Beanutils是一组专门用于操作Bean的工具类,目前很多流行的框架基本都离不开他。
版本:commons-beanutils-1.8.3.jar
1、获取字段值
2、设置字段值
3、赋值Bean
4、Bean的describe
5、Bean的populate
6、获取Bean的数组集合字段值
7、获取Bean的Map字段值
8、获取Bean的嵌套字段值
9、URL字段的特殊处理
10、日期的转化
Jodd的BeanUtil也提供了相当方便的操作Bean的API。
Apache Commons IO入门教程:http://www.importnew.com/13715.html
http://commons.apache.org/
1)Commons Lang是对JDK中java.lang包的补充,提供了各种各样的Utilities工具类,这里说说最常用的几个工具类。
版本:commons-lang3-3.1.jar
1、字符串的空判断
//isEmpty System.out.println(StringUtils.isEmpty(null)); // true System.out.println(StringUtils.isEmpty("")); // true System.out.println(StringUtils.isEmpty(" ")); // false System.out.println(StringUtils.isEmpty("bob")); // false System.out.println(StringUtils.isEmpty(" bob ")); // false //isBlank System.out.println(StringUtils.isBlank(null)); // true System.out.println(StringUtils.isBlank("")); // true System.out.println(StringUtils.isBlank(" ")); // true System.out.println(StringUtils.isBlank("bob")); // false System.out.println(StringUtils.isBlank(" bob ")); // false
2、字符串的Trim
//trim System.out.println(StringUtils.trim(null)); // null System.out.println(StringUtils.trim("")); // "" System.out.println(StringUtils.trim(" ")); // "" System.out.println(StringUtils.trim("abc")); // "abc" System.out.println(StringUtils.trim(" abc")); // "abc" System.out.println(StringUtils.trim(" abc ")); // "abc" System.out.println(StringUtils.trim(" ab c ")); // "ab c" //strip System.out.println(StringUtils.strip(null)); // null System.out.println(StringUtils.strip("")); // "" System.out.println(StringUtils.strip(" ")); // "" System.out.println(StringUtils.strip("abc")); // "abc" System.out.println(StringUtils.strip(" abc")); // "abc" System.out.println(StringUtils.strip("abc ")); // "abc" System.out.println(StringUtils.strip(" abc ")); // "abc" System.out.println(StringUtils.strip(" ab c ")); // "ab c" System.out.println(StringUtils.strip(" abcyx", "xyz")); // " abc" System.out.println(StringUtils.stripStart("yxabcxyz ", "xyz")); // "abcxyz " System.out.println(StringUtils.stripEnd(" xyzabcyx", "xyz")); // " xyzabc"
3、字符串的分割
//默认半角空格分割 String str1 = "aaa bbb ccc"; String[] dim1 = StringUtils.split(str1); // => ["aaa", "bbb", "ccc"] System.out.println(dim1.length);//3 System.out.println(dim1[0]);//"aaa" System.out.println(dim1[1]);//"bbb" System.out.println(dim1[2]);//"ccc" //指定分隔符 String str2 = "aaa,bbb,ccc"; String[] dim2 = StringUtils.split(str2, ","); // => ["aaa", "bbb", "ccc"] System.out.println(dim2.length);//3 System.out.println(dim2[0]);//"aaa" System.out.println(dim2[1]);//"bbb" System.out.println(dim2[2]);//"ccc" //去除空字符串 String str3 = "aaa,,bbb"; String[] dim3 = StringUtils.split(str3, ","); // => ["aaa", "bbb"] System.out.println(dim3.length);//2 System.out.println(dim3[0]);//"aaa" System.out.println(dim3[1]);//"bbb" //包含空字符串 String str4 = "aaa,,bbb"; String[] dim4 = StringUtils.splitPreserveAllTokens(str4, ","); // => ["aaa", "", "bbb"] System.out.println(dim4.length);//3 System.out.println(dim4[0]);//"aaa" System.out.println(dim4[1]);//"" System.out.println(dim4[2]);//"bbb" //指定分割的最大次数(超过后不分割) String str5 = "aaa,bbb,ccc"; String[] dim5 = StringUtils.split(str5, ",", 2); // => ["aaa", "bbb,ccc"] System.out.println(dim5.length);//2 System.out.println(dim5[0]);//"aaa" System.out.println(dim5[1]);//"bbb,ccc"
4、字符串的连接
//数组元素拼接 String[] array = {"aaa", "bbb", "ccc"}; String result1 = StringUtils.join(array, ","); System.out.println(result1);//"aaa,bbb,ccc" //集合元素拼接 List<String> list = new ArrayList<String>(); list.add("aaa"); list.add("bbb"); list.add("ccc"); String result2 = StringUtils.join(list, ","); System.out.println(result2);//"aaa,bbb,ccc"
5、字符串的Escape
System.out.println(StringEscapeUtils.escapeCsv("测试测试哦"));//"测试测试哦" System.out.println(StringEscapeUtils.escapeCsv("测试,测试哦"));//"\"测试,测试哦\"" System.out.println(StringEscapeUtils.escapeCsv("测试\n测试哦"));//"\"测试\n测试哦\"" System.out.println(StringEscapeUtils.escapeHtml4("测试测试哦 "));//"<p>测试测试哦</p>" System.out.println(StringEscapeUtils.escapeJava("\"rensaninng\",欢迎您!"));//"\"rensaninng\"\uFF0C\u6B22\u8FCE\u60A8\uFF01" System.out.println(StringEscapeUtils.escapeEcmaScript("测试'测试哦"));//"\u6D4B\u8BD5\'\u6D4B\u8BD5\u54E6" System.out.println(StringEscapeUtils.escapeXml("<tt>\"bread\" & \"butter\"</tt>"));//"<tt>"bread" & "butter"</tt>"
6、随机数
// 10位英字 System.out.println(RandomStringUtils.randomAlphabetic(10)); // 10位英数 System.out.println(RandomStringUtils.randomAlphanumeric(10)); // 10位ASCII码 System.out.println(RandomStringUtils.randomAscii(10)); // 指定文字10位 System.out.println(RandomStringUtils.random(10, "abcde"));
7、数组
// 追加元素到数组尾部 int[] array1 = {1, 2}; array1 = ArrayUtils.add(array1, 3); // => [1, 2, 3] System.out.println(array1.length);//3 System.out.println(array1[2]);//3 // 删除指定位置的元素 int[] array2 = {1, 2, 3}; array2 = ArrayUtils.remove(array2, 2); // => [1, 2] System.out.println(array2.length);//2 // 截取部分元素 int[] array3 = {1, 2, 3, 4}; array3 = ArrayUtils.subarray(array3, 1, 3); // => [2, 3] System.out.println(array3.length);//2 // 数组拷贝 String[] array4 = {"aaa", "bbb", "ccc"}; String[] copied = (String[]) ArrayUtils.clone(array4); // => {"aaa", "bbb", "ccc"} System.out.println(copied.length);//3 // 判断是否包含某元素 String[] array5 = {"aaa", "bbb", "ccc", "bbb"}; boolean result1 = ArrayUtils.contains(array5, "bbb"); // => true System.out.println(result1);//true // 判断某元素在数组中出现的位置(从前往后,没有返回-1) int result2 = ArrayUtils.indexOf(array5, "bbb"); // => 1 System.out.println(result2);//1 // 判断某元素在数组中出现的位置(从后往前,没有返回-1) int result3 = ArrayUtils.lastIndexOf(array5, "bbb"); // => 3 System.out.println(result3);//3 // 数组转Map Map<Object, Object> map = ArrayUtils.toMap(new String[][]{ {"key1", "value1"}, {"key2", "value2"} }); System.out.println(map.get("key1"));//"value1" System.out.println(map.get("key2"));//"value2" // 判断数组是否为空 Object[] array61 = new Object[0]; Object[] array62 = null; Object[] array63 = new Object[]{"aaa"}; System.out.println(ArrayUtils.isEmpty(array61));//true System.out.println(ArrayUtils.isEmpty(array62));//true System.out.println(ArrayUtils.isNotEmpty(array63));//true // 判断数组长度是否相等 Object[] array71 = new Object[]{"aa", "bb", "cc"}; Object[] array72 = new Object[]{"dd", "ee", "ff"}; System.out.println(ArrayUtils.isSameLength(array71, array72));//true // 判断数组元素内容是否相等 Object[] array81 = new Object[]{"aa", "bb", "cc"}; Object[] array82 = new Object[]{"aa", "bb", "cc"}; System.out.println(ArrayUtils.isEquals(array81, array82)); // Integer[] 转化为 int[] Integer[] array9 = new Integer[]{1, 2}; int[] result = ArrayUtils.toPrimitive(array9); System.out.println(result.length);//2 System.out.println(result[0]);//1 // int[] 转化为 Integer[] int[] array10 = new int[]{1, 2}; Integer[] result10 = ArrayUtils.toObject(array10); System.out.println(result.length);//2 System.out.println(result10[0].intValue());//1
8、日期
// 生成Date对象 Date date = DateUtils.parseDate("2010/01/01 11:22:33", new String[]{"yyyy/MM/dd HH:mm:ss"}); // 10天后 Date tenDaysAfter = DateUtils.addDays(date, 10); // => 2010/01/11 11:22:33 System.out.println(DateFormatUtils.format(tenDaysAfter, "yyyy/MM/dd HH:mm:ss")); // 前一个月 Date prevMonth = DateUtils.addMonths(date, -1); // => 2009/12/01 11:22:33 System.out.println(DateFormatUtils.format(prevMonth, "yyyy/MM/dd HH:mm:ss")); // 判断是否是同一天 Date date1 = DateUtils.parseDate("2010/01/01 11:22:33", new String[]{"yyyy/MM/dd HH:mm:ss"}); Date date2 = DateUtils.parseDate("2010/01/01 22:33:44", new String[]{"yyyy/MM/dd HH:mm:ss"}); System.out.println(DateUtils.isSameDay(date1, date2));// true // 日期格式化 System.out.println(DateFormatUtils.format(new Date(), "yyyy/MM/dd HH:mm:ss"));
2)Commons Beanutils是一组专门用于操作Bean的工具类,目前很多流行的框架基本都离不开他。
版本:commons-beanutils-1.8.3.jar
1、获取字段值
SampleBean bean1 = new SampleBean(); bean1.setName("rensanning"); bean1.setAge(31); String name = BeanUtils.getProperty(bean1, "name"); String age = BeanUtils.getProperty(bean1, "age"); System.out.println(name); System.out.println(age);
2、设置字段值
SampleBean bean2 = new SampleBean(); BeanUtils.setProperty(bean2, "name", "rensanning"); BeanUtils.setProperty(bean2, "age", 31); System.out.println(bean2.getName()); System.out.println(bean2.getAge());
3、赋值Bean
SampleBean bean3 = new SampleBean(); bean3.setName("rensanning"); bean3.setAge(31); SampleBean clone = (SampleBean) BeanUtils.cloneBean(bean3); System.out.println(clone.getName()); System.out.println(clone.getAge());
4、Bean的describe
SampleBean bean4 = new SampleBean(); bean4.setName("rensanning"); bean4.setAge(31); @SuppressWarnings("unchecked") Map<String, String> map4 = BeanUtils.describe(bean4); System.out.println(map4.get("name")); System.out.println(map4.get("age"));
5、Bean的populate
SampleBean bean5 = new SampleBean(); Map<String, String> map5 = new HashMap<String, String>(); map5.put("name", "rensanning"); map5.put("age", "31"); BeanUtils.populate(bean5, map5); System.out.println(bean5.getName()); System.out.println(bean5.getAge());
6、获取Bean的数组集合字段值
SampleBean bean6 = new SampleBean(); bean6.setArray(new String[]{"a", "b", "c"}); List<String> list0 = new ArrayList<String>(); list0.add("d"); list0.add("e"); list0.add("f"); bean6.setList(list0); String[] array = BeanUtils.getArrayProperty(bean6, "array"); System.out.println(array.length);//3 System.out.println(array[0]);//"a" System.out.println(array[1]);//"b" System.out.println(array[2]);//"c" String[] list = BeanUtils.getArrayProperty(bean6, "list"); System.out.println(list.length);//3 System.out.println(list[0]);//"d" System.out.println(list[1]);//"e" System.out.println(list[2]);//"f" System.out.println(BeanUtils.getProperty(bean6, "array[1]"));//"b" System.out.println(BeanUtils.getIndexedProperty(bean6, "array", 2));//"c"
7、获取Bean的Map字段值
SampleBean bean7 = new SampleBean(); Map<String, String> map = new HashMap<String, String>(); map.put("key1", "value1"); map.put("key2", "value2"); bean7.setMap(map); String value1 = BeanUtils.getMappedProperty(bean7, "map", "key1"); System.out.println(value1);//"value1" String value2 = BeanUtils.getMappedProperty(bean7, "map", "key2"); System.out.println(value2);//"value2" System.out.println(BeanUtils.getProperty(bean7, "map.key1"));//"value1" System.out.println(BeanUtils.getProperty(bean7, "map.key2"));//"value2"
8、获取Bean的嵌套字段值
SampleBean bean = new SampleBean(); NestedBean nestedBean = new NestedBean(); nestedBean.setNestedProperty("xxx"); bean.setNestedBean(nestedBean); String value = BeanUtils.getNestedProperty(bean, "nestedBean.nestedProperty"); System.out.println(value);//"xxx" System.out.println(BeanUtils.getProperty(bean, "nestedBean.nestedProperty"));//"xxx"
9、URL字段的特殊处理
SampleBean bean8 = new SampleBean(); BeanUtils.setProperty(bean8, "url", "http://www.google.com/"); URL url = bean8.getUrl(); System.out.println(url.getProtocol());//"http" System.out.println(url.getHost());//"www.google.com" System.out.println(url.getPath());//"/"
10、日期的转化
SampleBean bean9 = new SampleBean(); DateConverter converter = new DateConverter(); converter.setPattern("yyyy/MM/dd HH:mm:ss"); ConvertUtils.register(converter, Date.class); ConvertUtils.register(converter, String.class); BeanUtils.setProperty(bean9, "date", "2010/12/19 23:40:00"); String value9 = BeanUtils.getProperty(bean9, "date"); System.out.println(value9);//"2010/12/19 23:40:00"
Jodd的BeanUtil也提供了相当方便的操作Bean的API。
Apache Commons IO入门教程:http://www.importnew.com/13715.html