正则表达式测试
Pattern、Matcher等与正则表达式相关类的文档见JDK API文档，以及下面注释的博客链接。
一、Pattern类测试
import java.util.Arrays;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Pattern/Matcher 测试
* 参考博客：
* https://my.oschina.net/CasparLi/blog/361859
* https://winter8.iteye.com/blog/1463244
*/
public class PatternTest {
public static void main(String[] args) {
// \w+ 匹配一个或多个字母、数字、下划线
Pattern p1 = Pattern.compile("\\w+");
// 正则表达式
String patternString = p1.pattern();
System.out.println(patternString);
// \d+ 匹配一个或多个数字 Pattern.split分割
Pattern p2 = Pattern.compile("\\d+");
String[] str = p2.split("我的QQ是:456456我的电话是:0532214我的邮箱是:[email protected]");
System.out.println(Arrays.toString(str));
// Pattern.matches 匹配全部，才返回true
System.out.println(Pattern.matches("\\d+", "23333"));
System.out.println(Pattern.matches("\\d+", "23333aa"));
System.out.println(Pattern.matches("\\d+", "233bb33"));
Matcher matcher = p2.matcher("222333bb44");
// 返回p 也就是返回该Matcher对象是由哪个Pattern对象的创建的
System.out.println(matcher.pattern());
// Matcher.matches() 匹配全部，才返回true
Matcher m1 = p2.matcher("22bb33");
// 返回false,因为bb不能被\d+匹配,导致整个字符串匹配未成功.
System.out.println("Matcher.matches(): " + m1.matches()/* + ", start: " + m1.start() + ";end: " + m1.end()*/);
// 返回true,因为\d+匹配到了整个字符串
Matcher m2 = p2.matcher("2233");
System.out.println("Matcher.matches(): " + m2.matches() + ", start: " + m2.start() + ";end: " + m2.end());
// Matcher.lookingAt() 字符串开始处开始匹配
Matcher m3 = p2.matcher("22bb333");
// 返回true,因为\d+匹配到了前面的22
System.out.println("Matcher.lookingAt(): " + m3.lookingAt() + ", start: " + m3.start() + ";end: " + m3.end());
// 返回false,因为\d+不能匹配前面的bb
Matcher m4 = p2.matcher("bb2233");
System.out.println("Matcher.lookingAt(): " + m4.lookingAt()/* + ", start: " + m4.start() + ";end: " + m4.end()*/);
// Matcher.find() 匹配到的字符串可以在任何位置
Matcher m5 = p2.matcher("22bb23");
System.out.println("m5.find(): " + m5.find());
Matcher m6 = p2.matcher("aa2223");
System.out.println("m6.find(): " + m6.find());
Matcher m7 = p2.matcher("aa2223bb");
System.out.println("m7.find(): " + m7.find());
Matcher m8 = p2.matcher("aabb");
System.out.println("m8.find(): " + m8.find());
}
}
/*输出：
\w+
[我的QQ是:, 我的电话是:, 我的邮箱是:[email protected]]
true
false
false
\d+
Matcher.matches(): false
Matcher.matches(): true, start: 0;end: 4
Matcher.lookingAt(): true, start: 0;end: 2
Matcher.lookingAt(): false
m5.find(): true
m6.find(): true
m7.find(): true
m8.find(): false
*/
二、Matcher类测试
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Matcher 测试
*/
public class MatcherTest {
private static final Pattern PATTERN = Pattern.compile("\\d+");
public static void main(String[] args){
// find() 对字符串进行匹配,匹配到的字符串可以在任何位置
Matcher m = PATTERN.matcher("aaa2223bb");
System.out.println("m.find(): " + m.find());
System.out.println("m.start(): " + m.start());
System.out.println("m.end(): " + m.end());
System.out.println("m.group(): " + m.group());
System.out.println("--------------------");
// lookingAt() 对前面的字符串进行匹配,只有匹配到的字符串在最前面才返回true
Matcher m2 = PATTERN.matcher("2223bb");
System.out.println("m2.lookingAt(): " + m2.lookingAt());
System.out.println("m2.start(): " + m2.start());
System.out.println("m2.end(): " + m2.end());
System.out.println("m2.group(): " + m2.group());
System.out.println("---------------------");
// matches()
Matcher m3 = PATTERN.matcher("2223bb");
// matches() 对整个字符串进行匹配,只有整个字符串都匹配了才返回true
System.out.println("m3.matches(): " + m3.matches());
// System.out.println("m3.start(): " + m3.start()); // 异常
// System.out.println("m3.end(): " + m3.end()); // 异常
// System.out.println("m3.group(): " + m3.group()); // 异常
}
}
/*输出:
m.find(): true
m.start(): 3
m.end(): 7
m.group(): 2223
--------------------
m2.lookingAt(): true
m2.start(): 0
m2.end(): 4
m2.group(): 2223
---------------------
m3.matches(): false
*/
三、正则表达式(捕获分组)测试
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* 正则表达式分组group测试
*/
public class GroupTest {
private static final Pattern PATTERN_ONE = Pattern.compile("([a-z]+)(\\d+)");
private static final Pattern PATTERN_TWO = Pattern.compile("(\\d+)");
public static void main(String[] args) {
Matcher m = PATTERN_ONE.matcher("aaa2223bb111");
// 对字符串进行匹配,匹配到的子字符串序列可以在任何位置
while (m.find()) {
System.out.println("***********");
// group() 等于 group(0) 表示匹配的子字符串序列
System.out.println("m.group(0): " + m.group(0));
System.out.println("m.start(0): " + m.start(0) + ", m.end(1): " + m.end(0));
// gropu(1) 正则表达式第一个括号，start(1)、end(1)与group(1)对应
System.out.println("m.group(1): " + m.group(1));
System.out.println("m.start(1): " + m.start(1) + ", m.end(1): " + m.end(1));
// gropu(2) 正则表达式第二个括号
System.out.println("m.group(2): " + m.group(2));
System.out.println("m.start(2): " + m.start(2) + ", m.end(2): " + m.end(2));
}
// 2
System.out.println("m.groupCount(): " + m.groupCount());
// false
System.out.println("m.find(): " + m.find());
// System.out.println("m.group(0): " + m.group(0));
// System.out.println("m.start(0): " + m.start(0) + ", m.end(1): " + m.end(0));
// System.out.println("m.group(1): " + m.group(1));
// System.out.println("m.start(1): " + m.start(1) + ", m.end(1): " + m.end(1));
// System.out.println("m.group(2): " + m.group(2));
// System.out.println("m.start(2): " + m.start(2) + ", m.end(2): " + m.end(2));
System.out.println("--------------------------");
Matcher m2 = PATTERN_TWO.matcher("我的QQ是:456456 我的电话是:0532214 我的邮箱是:[email protected]");
while (m2.find()) {
System.out.println(m2.group() + ", start: " + m2.start() + ",end: " + m2.end());
}
}
}
/*输出:
***********
m.group(0): aaa2223
m.start(0): 0, m.end(1): 7
m.group(1): aaa
m.start(1): 0, m.end(1): 3
m.group(2): 2223
m.start(2): 3, m.end(2): 7
***********
m.group(0): bb111
m.start(0): 7, m.end(1): 12
m.group(1): bb
m.start(1): 7, m.end(1): 9
m.group(2): 111
m.start(2): 9, m.end(2): 12
m.groupCount(): 2
m.find(): false
--------------------------
456456, start: 6,end: 12
0532214, start: 19,end: 26
123, start: 36,end: 39
*/
