Java工具类之Apache的Commons Lang和BeanUtils

本文深入探讨了Apache Commons包在Java开发中的应用,着重介绍了CommonsLang工具类的功能,包括字符串处理、随机数生成、数组操作、日期处理等,并详细展示了如何使用CommonsBeanutils操作Bean。通过实例代码,全面展示了这些工具类的强大功能。

摘要生成于 C知道 ,由 DeepSeek-R1 满血版支持, 前往体验 >

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

?
1
2
3
4
5
6
7
8
9
10
11
12
13
//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
?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
//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
?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
//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
?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
//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
?
1
2
3
4
5
6
7
8
9
10
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" &amp; "butter"</tt>"


6、随机数
?
1
2
3
4
5
6
7
8
9
10
11
// 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
?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
// 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
?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
// 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

?
1
2
3
4
5
6
7
8
9
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
?
1
2
3
4
5
6
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
?
1
2
3
4
5
6
7
8
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
?
1
2
3
4
5
6
7
8
9
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
?
1
2
3
4
5
6
7
8
9
10
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
?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
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
?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
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
?
1
2
3
4
5
6
7
8
9
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
?
1
2
3
4
5
6
7
8
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
?
1
2
3
4
5
6
7
8
9
10
11
12
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"
转自:http://rensanning.iteye.com/blog/1547845
评论
添加红包

请填写红包祝福语或标题

红包个数最小为10个

红包金额最低5元

当前余额3.43前往充值 >
需支付:10.00
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明:

1.余额是钱包充值的虚拟货币,按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载,可以购买VIP、付费专栏及课程。

余额充值