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