Java 正则表达式入门详解(基础进阶)

import java.util.regex.*; 
class RegexExample1{
 public static void main(String args[]){
 String content = "I am mdxy " +
 "from jb51.net";
 
 String pattern = ".*jb51.*";
 
 boolean isMatch = Pattern.matches(pattern, content);
 System.out.println("字符串中是否包含了'jb51'子字符串" + isMatch);
 }
} 

import java.util.regex.Matcher;
import java.util.regex.Pattern;
 
public class RegexMatches
{
 public static void main( String args[] ){
 
 // 按指定模式在字符串查找
 String line = "This order was placed for QT3000! OK?";
 String pattern = "(\\D*)(\\d+)(.*)";
 
 // 创建 Pattern 对象
 Pattern r = Pattern.compile(pattern);
 
 // 现在创建 matcher 对象
 Matcher m = r.matcher(line);
 if (m.find( )) {
  System.out.println("Found value: " + m.group(0) );
  System.out.println("Found value: " + m.group(1) );
  System.out.println("Found value: " + m.group(2) );
  System.out.println("Found value: " + m.group(3) ); 
 } else {
  System.out.println("NO MATCH");
 }
 }
}

import java.util.regex.Matcher;
import java.util.regex.Pattern;
 
public class RegexMatches
{
 private static final String REGEX = "\\bcat\\b";
 private static final String INPUT =
     "cat cat cat cattie cat";
 
 public static void main( String args[] ){
 Pattern p = Pattern.compile(REGEX);
 Matcher m = p.matcher(INPUT); // 获取 matcher 对象
 int count = 0;
 
 while(m.find()) {
  count++;
  System.out.println("Match number "+count);
  System.out.println("start(): "+m.start());
  System.out.println("end(): "+m.end());
 }
 }
}

import java.util.regex.Matcher;
import java.util.regex.Pattern;
 
public class RegexMatches
{
 private static final String REGEX = "foo";
 private static final String INPUT = "fooooooooooooooooo";
 private static final String INPUT2 = "ooooofoooooooooooo";
 private static Pattern pattern;
 private static Matcher matcher;
 private static Matcher matcher2;
 
 public static void main( String args[] ){
 pattern = Pattern.compile(REGEX);
 matcher = pattern.matcher(INPUT);
 matcher2 = pattern.matcher(INPUT2);
 
 System.out.println("Current REGEX is: "+REGEX);
 System.out.println("Current INPUT is: "+INPUT);
 System.out.println("Current INPUT2 is: "+INPUT2);
 
 
 System.out.println("lookingAt(): "+matcher.lookingAt());
 System.out.println("matches(): "+matcher.matches());
 System.out.println("lookingAt(): "+matcher2.lookingAt());
 }
}

import java.util.regex.Matcher;
import java.util.regex.Pattern;
 
public class RegexMatches
{
 private static String REGEX = "dog";
 private static String INPUT = "The dog says meow. " +
     "All dogs say meow.";
 private static String REPLACE = "cat";
 
 public static void main(String[] args) {
 Pattern p = Pattern.compile(REGEX);
 // get a matcher object
 Matcher m = p.matcher(INPUT); 
 INPUT = m.replaceAll(REPLACE);
 System.out.println(INPUT);
 }
}

import java.util.regex.Matcher;
import java.util.regex.Pattern;
 
public class RegexMatches
{
 private static String REGEX = "a*b";
 private static String INPUT = "aabfooaabfooabfoob";
 private static String REPLACE = "-";
 public static void main(String[] args) {
 Pattern p = Pattern.compile(REGEX);
 // 获取 matcher 对象
 Matcher m = p.matcher(INPUT);
 StringBuffer sb = new StringBuffer();
 while(m.find()){
  m.appendReplacement(sb,REPLACE);
 }
 m.appendTail(sb);
 System.out.println(sb.toString());
 }
}

public static void main(String[] args) {
 // 要验证的字符串
 String str = "service@xsoftlab.net";
 // 邮箱验证规则
 String regEx = "[a-zA-Z_]{1,}[0-9]{0,}@(([a-zA-z0-9]-*){1,}\\.){1,3}[a-zA-z\\-]{1,}";
 // 编译正则表达式
 Pattern pattern = Pattern.compile(regEx);
 // 忽略大小写的写法
 // Pattern pat = Pattern.compile(regEx, Pattern.CASE_INSENSITIVE);
 Matcher matcher = pattern.matcher(str);
 // 字符串是否与正则表达式相匹配
 boolean rs = matcher.matches();
 System.out.println(rs);
}

public static void main(String[] args) {
 // 要验证的字符串
 String str = "baike.xsoftlab.net";
 // 正则表达式规则
 String regEx = "baike.*";
 // 编译正则表达式
 Pattern pattern = Pattern.compile(regEx);
 // 忽略大小写的写法
 // Pattern pat = Pattern.compile(regEx, Pattern.CASE_INSENSITIVE);
 Matcher matcher = pattern.matcher(str);
 // 查找字符串中是否有匹配正则表达式的字符/字符串
 boolean rs = matcher.find();
 System.out.println(rs);
}