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
转自:http://rensanning.iteye.com/blog/1547845
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
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//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
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2、字符串的Trim
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//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"
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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);
//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"
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4、字符串的连接
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//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"
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5、字符串的Escape
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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>"
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6、随机数
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// 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
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// 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
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8、日期
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// 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"
));
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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
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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);
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2、设置字段值
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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
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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());
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4、Bean的describe
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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"
));
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5、Bean的populate
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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());
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6、获取Bean的数组集合字段值
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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"
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7、获取Bean的Map字段值
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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"
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8、获取Bean的嵌套字段值
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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"
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9、URL字段的特殊处理
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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
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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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