JAVA工具类之Apache的Commons Lang和Beanutils
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。
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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
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1.字符串的空判断。
//isEmptySystem.out.println(StringUtils.isEmpty(null)); // trueSystem.out.println(StringUtils.isEmpty("")); // trueSystem.out.println(StringUtils.isEmpty(" ")); // falseSystem.out.println(StringUtils.isEmpty("bob")); // falseSystem.out.println(StringUtils.isEmpty(" bob ")); // false//isBlankSystem.out.println(StringUtils.isBlank(null)); // trueSystem.out.println(StringUtils.isBlank("")); // trueSystem.out.println(StringUtils.isBlank(" ")); // trueSystem.out.println(StringUtils.isBlank("bob")); // falseSystem.out.println(StringUtils.isBlank(" bob ")); // false?
2.字符串的trim
//trimSystem.out.println(StringUtils.trim(null)); // nullSystem.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"//stripSystem.out.println(StringUtils.strip(null)); // nullSystem.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
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//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);//3System.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);//3System.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);//2System.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);//3System.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);//2System.out.println(dim5[0]);//"aaa"System.out.println(dim5[1]);//"bbb,ccc"
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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"));
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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);//3System.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"); // => trueSystem.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"); // => 1System.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"); // => 3System.out.println(result3);//3// 数组转MapMap<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));//trueSystem.out.println(ArrayUtils.isEmpty(array62));//trueSystem.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);//2System.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);//2System.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 11:22:33System.out.println(DateFormatUtils.format(tenDaysAfter, "yyyy/MM/dd HH:mm:ss"));// 前一个月Date prevMonth = DateUtils.addMonths(date, -1); // => 2009/12/01 11:22:33System.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?
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1.获取字段的值
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.设置字段的值
SampleBean bean2 = new SampleBean();BeanUtils.setProperty(bean2, "name", "rensanning");BeanUtils.setProperty(bean2, "age", 31);System.out.println(bean2.getName());System.out.println(bean2.getAge());
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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);//3System.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);//3System.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());//"/"
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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"?
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