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。

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

01

//isEmpty

02	System.out.println(StringUtils.isEmpty(null));// true

03	System.out.println(StringUtils.isEmpty(""));// true

04	System.out.println(StringUtils.isEmpty(" "));// false

05	System.out.println(StringUtils.isEmpty("bob"));// false

06	System.out.println(StringUtils.isEmpty(" bob "));// false

07

08

//isBlank

09	System.out.println(StringUtils.isBlank(null));// true

10	System.out.println(StringUtils.isBlank(""));// true

11	System.out.println(StringUtils.isBlank(" "));// true

12	System.out.println(StringUtils.isBlank("bob"));// false

13	System.out.println(StringUtils.isBlank(" bob "));// false

2、字符串的Trim

01

//trim

02	System.out.println(StringUtils.trim(null));// null

03	System.out.println(StringUtils.trim(""));// ""

04	System.out.println(StringUtils.trim(" "));// ""

05	System.out.println(StringUtils.trim("abc"));// "abc"

06	System.out.println(StringUtils.trim(" abc"));// "abc"

07	System.out.println(StringUtils.trim(" abc "));// "abc"

08	System.out.println(StringUtils.trim(" ab c "));// "ab c"

09

10

//strip

11	System.out.println(StringUtils.strip(null));// null

12	System.out.println(StringUtils.strip(""));// ""

13	System.out.println(StringUtils.strip(" "));// ""

14	System.out.println(StringUtils.strip("abc"));// "abc"

15	System.out.println(StringUtils.strip(" abc"));// "abc"

16	System.out.println(StringUtils.strip("abc "));// "abc"

17	System.out.println(StringUtils.strip(" abc "));// "abc"

18	System.out.println(StringUtils.strip(" ab c "));// "ab c"

19

20	System.out.println(StringUtils.strip(" abcyx","xyz"));// " abc"

21

22	System.out.println(StringUtils.stripStart("yxabcxyz ","xyz"));// "abcxyz "

23	System.out.println(StringUtils.stripEnd(" xyzabcyx","xyz"));// " xyzabc"

3、字符串的分割

01	//默认半角空格分割

02	String str1 ="aaa bbb ccc";

03	String[] dim1 = StringUtils.split(str1);// => ["aaa", "bbb", "ccc"]

04

05	System.out.println(dim1.length);//3

06	System.out.println(dim1[0]);//"aaa"

07	System.out.println(dim1[1]);//"bbb"

08	System.out.println(dim1[2]);//"ccc"

09

10

//指定分隔符

11	String str2 ="aaa,bbb,ccc";

12	String[] dim2 = StringUtils.split(str2,",");// => ["aaa", "bbb", "ccc"]

13

14	System.out.println(dim2.length);//3

15	System.out.println(dim2[0]);//"aaa"

16	System.out.println(dim2[1]);//"bbb"

17	System.out.println(dim2[2]);//"ccc"

18

19

//去除空字符串

20	String str3 ="aaa,,bbb";

21	String[] dim3 = StringUtils.split(str3,",");// => ["aaa", "bbb"]

22

23	System.out.println(dim3.length);//2

24	System.out.println(dim3[0]);//"aaa"

25	System.out.println(dim3[1]);//"bbb"

26

27

//包含空字符串

28	String str4 ="aaa,,bbb";

29	String[] dim4 = StringUtils.splitPreserveAllTokens(str4,",");// => ["aaa", "", "bbb"]

30

31	System.out.println(dim4.length);//3

32	System.out.println(dim4[0]);//"aaa"

33	System.out.println(dim4[1]);//""

34	System.out.println(dim4[2]);//"bbb"

35

36	//指定分割的最大次数（超过后不分割）

37	String str5 ="aaa,bbb,ccc";

38	String[] dim5 = StringUtils.split(str5,",", 2);// => ["aaa", "bbb,ccc"]

39

40	System.out.println(dim5.length);//2

41	System.out.println(dim5[0]);//"aaa"

42	System.out.println(dim5[1]);//"bbb,ccc"

4、字符串的连接

01

//数组元素拼接

02	String[] array = {"aaa","bbb","ccc"};

03	String result1 = StringUtils.join(array,",");

04

05	System.out.println(result1);//"aaa,bbb,ccc"

06

07

//集合元素拼接

08	List<String> list =newArrayList<String>();

09	list.add("aaa");

10	list.add("bbb");

11	list.add("ccc");

12	String result2 = StringUtils.join(list,",");

13

14	System.out.println(result2);//"aaa,bbb,ccc"

5、字符串的Escape

01	System.out.println(StringEscapeUtils.escapeCsv("测试测试哦"));//"测试测试哦"

02	System.out.println(StringEscapeUtils.escapeCsv("测试,测试哦"));//"\"测试,测试哦\""

03	System.out.println(StringEscapeUtils.escapeCsv("测试\n测试哦"));//"\"测试\n测试哦\""

04

05	System.out.println(StringEscapeUtils.escapeHtml4("测试测试哦

06	"));//"<p>测试测试哦</p>"

07	System.out.println(StringEscapeUtils.escapeJava("\"rensaninng\"，欢迎您！"));//"\"rensaninng\"\uFF0C\u6B22\u8FCE\u60A8\uFF01"

08

09	System.out.println(StringEscapeUtils.escapeEcmaScript("测试'测试哦"));//"\u6D4B\u8BD5\'\u6D4B\u8BD5\u54E6"

10	System.out.println(StringEscapeUtils.escapeXml("<tt>\"bread\" & \"butter\"</tt>"));//"<tt>"bread" &amp; "butter"</tt>"

6、随机数

01

// 10位英字

02	System.out.println(RandomStringUtils.randomAlphabetic(10));

03

04

// 10位英数

05	System.out.println(RandomStringUtils.randomAlphanumeric(10));

06

07	// 10位ASCII码

08	System.out.println(RandomStringUtils.randomAscii(10));

09

10	// 指定文字10位

11	System.out.println(RandomStringUtils.random(10,"abcde"));

7、数组

01	// 追加元素到数组尾部

02	int[] array1 = {1, 2};

03	array1 = ArrayUtils.add(array1, 3);// => [1, 2, 3]

04

05	System.out.println(array1.length);//3

06	System.out.println(array1[2]);//3

07

08	// 删除指定位置的元素

09	int[] array2 = {1, 2, 3};

10	array2 = ArrayUtils.remove(array2, 2);// => [1, 2]

11

12	System.out.println(array2.length);//2

13

14

// 截取部分元素

15	int[] array3 = {1, 2, 3, 4};

16	array3 = ArrayUtils.subarray(array3, 1, 3);// => [2, 3]

17

18	System.out.println(array3.length);//2

19

20

// 数组拷贝

21	String[] array4 = {"aaa","bbb","ccc"};

22	String[] copied = (String[]) ArrayUtils.clone(array4);// => {"aaa", "bbb", "ccc"}

23

24	System.out.println(copied.length);//3

25

26	// 判断是否包含某元素

27	String[] array5 = {"aaa","bbb","ccc","bbb"};

28	boolean result1 = ArrayUtils.contains(array5,"bbb");// => true

29	System.out.println(result1);//true

30

31	// 判断某元素在数组中出现的位置（从前往后，没有返回-1）

32	int result2 = ArrayUtils.indexOf(array5,"bbb");// => 1

33	System.out.println(result2);//1

34

35	// 判断某元素在数组中出现的位置（从后往前，没有返回-1）

36	int result3 = ArrayUtils.lastIndexOf(array5,"bbb");// => 3

37	System.out.println(result3);//3

38

39

// 数组转Map

40	Map<Object, Object> map = ArrayUtils.toMap(newString[][]{

41	{"key1","value1"},

42	{"key2","value2"}

43

});

44	System.out.println(map.get("key1"));//"value1"

45	System.out.println(map.get("key2"));//"value2"

46

47	// 判断数组是否为空

48	Object[] array61 =newObject[0];

49	Object[] array62 =null;

50	Object[] array63 =newObject[]{"aaa"};

51

52	System.out.println(ArrayUtils.isEmpty(array61));//true

53	System.out.println(ArrayUtils.isEmpty(array62));//true

54	System.out.println(ArrayUtils.isNotEmpty(array63));//true

55

56	// 判断数组长度是否相等

57	Object[] array71 =newObject[]{"aa","bb","cc"};

58	Object[] array72 =newObject[]{"dd","ee","ff"};

59

60	System.out.println(ArrayUtils.isSameLength(array71, array72));//true

61

62	// 判断数组元素内容是否相等

63	Object[] array81 =newObject[]{"aa","bb","cc"};

64	Object[] array82 =newObject[]{"aa","bb","cc"};

65

66	System.out.println(ArrayUtils.isEquals(array81, array82));

67

68	// Integer[] 转化为 int[]

69	Integer[] array9 =newInteger[]{1, 2};

70	int[] result = ArrayUtils.toPrimitive(array9);

71

72	System.out.println(result.length);//2

73	System.out.println(result[0]);//1

74

75	// int[] 转化为 Integer[]

76	int[] array10 =newint[]{1, 2};

77	Integer[] result10 = ArrayUtils.toObject(array10);

78

79	System.out.println(result.length);//2

80	System.out.println(result10[0].intValue());//1

8、日期

01	// 生成Date对象

02	Date date = DateUtils.parseDate("2010/01/01 11:22:33",newString[]{"yyyy/MM/dd HH:mm:ss"});

03

04

// 10天后

05	Date tenDaysAfter = DateUtils.addDays(date, 10);// => 2010/01/11 11:22:33

06	System.out.println(DateFormatUtils.format(tenDaysAfter,"yyyy/MM/dd HH:mm:ss"));

07

08

// 前一个月

09	Date prevMonth = DateUtils.addMonths(date, -1);// => 2009/12/01 11:22:33

10	System.out.println(DateFormatUtils.format(prevMonth,"yyyy/MM/dd HH:mm:ss"));

11

12	// 判断是否是同一天

13	Date date1 = DateUtils.parseDate("2010/01/01 11:22:33",newString[]{"yyyy/MM/dd HH:mm:ss"});

14	Date date2 = DateUtils.parseDate("2010/01/01 22:33:44",newString[]{"yyyy/MM/dd HH:mm:ss"});

15	System.out.println(DateUtils.isSameDay(date1, date2));// true

16

17

// 日期格式化

18	System.out.println(DateFormatUtils.format(newDate(),"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

1	SampleBean bean1 =newSampleBean();

2	bean1.setName("rensanning");

3	bean1.setAge(31);

4

5	String name = BeanUtils.getProperty(bean1,"name");

6	String age = BeanUtils.getProperty(bean1,"age");

7

8	System.out.println(name);

9	System.out.println(age);

2、设置字段值

1	SampleBean bean2 =newSampleBean();

2	BeanUtils.setProperty(bean2,"name","rensanning");

3	BeanUtils.setProperty(bean2,"age", 31);

4

5	System.out.println(bean2.getName());

6	System.out.println(bean2.getAge());

3、赋值Bean

1	SampleBean bean3 =newSampleBean();

2	bean3.setName("rensanning");

3	bean3.setAge(31);

4

5	SampleBean clone = (SampleBean) BeanUtils.cloneBean(bean3);

6

7	System.out.println(clone.getName());

8	System.out.println(clone.getAge());

4、Bean的describe

1	SampleBean bean4 =newSampleBean();

2	bean4.setName("rensanning");

3	bean4.setAge(31);

4

5	@SuppressWarnings("unchecked")

6	Map<String, String> map4 = BeanUtils.describe(bean4);

7

8	System.out.println(map4.get("name"));

9	System.out.println(map4.get("age"));

5、Bean的populate

01	SampleBean bean5 =newSampleBean();

02

03	Map<String, String> map5 =newHashMap<String, String>();

04	map5.put("name","rensanning");

05	map5.put("age","31");

06

07	BeanUtils.populate(bean5, map5);

08

09	System.out.println(bean5.getName());

10	System.out.println(bean5.getAge());

6、获取Bean的数组集合字段值

01	SampleBean bean6 =newSampleBean();

02	bean6.setArray(newString[]{"a","b","c"});

03	List<String> list0 =newArrayList<String>();

04	list0.add("d");

05	list0.add("e");

06	list0.add("f");

07	bean6.setList(list0);

08

09	String[] array = BeanUtils.getArrayProperty(bean6,"array");

10

11	System.out.println(array.length);//3

12	System.out.println(array[0]);//"a"

13	System.out.println(array[1]);//"b"

14	System.out.println(array[2]);//"c"

15

16	String[] list = BeanUtils.getArrayProperty(bean6,"list");

17	System.out.println(list.length);//3

18	System.out.println(list[0]);//"d"

19	System.out.println(list[1]);//"e"

20	System.out.println(list[2]);//"f"

21

22	System.out.println(BeanUtils.getProperty(bean6,"array[1]"));//"b"

23	System.out.println(BeanUtils.getIndexedProperty(bean6,"array", 2));//"c"

7、获取Bean的Map字段值

01	SampleBean bean7 =newSampleBean();

02	Map<String, String> map =newHashMap<String, String>();

03	map.put("key1","value1");

04	map.put("key2","value2");

05	bean7.setMap(map);

06

07	String value1 = BeanUtils.getMappedProperty(bean7,"map","key1");

08	System.out.println(value1);//"value1"

09

10	String value2 = BeanUtils.getMappedProperty(bean7,"map","key2");

11	System.out.println(value2);//"value2"

12

13	System.out.println(BeanUtils.getProperty(bean7,"map.key1"));//"value1"

14	System.out.println(BeanUtils.getProperty(bean7,"map.key2"));//"value2"

8、获取Bean的嵌套字段值

1	SampleBean bean =newSampleBean();

2	NestedBean nestedBean =newNestedBean();

3	nestedBean.setNestedProperty("xxx");

4	bean.setNestedBean(nestedBean);

5

6	String value = BeanUtils.getNestedProperty(bean,"nestedBean.nestedProperty");

7	System.out.println(value);//"xxx"

8

9	System.out.println(BeanUtils.getProperty(bean,"nestedBean.nestedProperty"));//"xxx"

9、URL字段的特殊处理

1	SampleBean bean8 =newSampleBean();

2

3	BeanUtils.setProperty(bean8,"url","http://www.google.com/");

4

5	URL url = bean8.getUrl();

6	System.out.println(url.getProtocol());//"http"

7	System.out.println(url.getHost());//"www.google.com"

8	System.out.println(url.getPath());//"/"

10、日期的转化

01	SampleBean bean9 =newSampleBean();

02

03	DateConverter converter =newDateConverter();

04	converter.setPattern("yyyy/MM/dd HH:mm:ss");

05

06	ConvertUtils.register(converter, Date.class);

07	ConvertUtils.register(converter, String.class);

08

09	BeanUtils.setProperty(bean9,"date","2010/12/19 23:40:00");

10

11	String value9 = BeanUtils.getProperty(bean9,"date");

12	System.out.println(value9);//"2010/12/19 23:40:00"

该类文章相关链接：

http://rensanning.iteye.com/blog/1548162Java集合框架之fastutil
http://rensanning.iteye.com/blog/1547845Java工具类之Apache的Commons Lang和BeanUtils
http://rensanning.iteye.com/blog/1546652Java日期计算之Joda-Time
http://rensanning.iteye.com/blog/1545708Java生成缩略图之Thumbnailator
http://rensanning.iteye.com/blog/1540613模板引擎之FreeMarker超入门
http://rensanning.iteye.com/blog/1540336Java构建工具之Ant超入门
http://rensanning.iteye.com/blog/1538689Java操作PDF之iText超入门
http://rensanning.iteye.com/blog/1538591Java读写Excel之POI超入门

转自：http://rensanning.iteye.com/blog/1547845