1、查詢字串中的字串

package com.wy.regular;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class RegularTest {

    public static void main(String[] args) {
        /**
         * 字串的替換 replacement
         */
        Pattern pattern = Pattern.compile("java");
        Matcher matcher = pattern.matcher("java Java JAVa JaVa I love JAVA you hate Java");
        // 查詢所有的Java
        while (matcher.find()) {
            pri(matcher.group());// 只有一個java
        }
    }

    public static void pri(Object object){
        System.out.println(object);
    }
}
 

2、忽略大小寫

package com.wy.regular;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class RegularTest {

    public static void main(String[] args) {
        /**
         * 字串的替換 replacement
         * 使用compile(String regex, int flags)方法
         * CASE_INSENSITIVE 大小寫不敏感，忽略大小寫
         */
        Pattern pattern = Pattern.compile("java", Pattern.CASE_INSENSITIVE);
        Matcher matcher = pattern.matcher("java Java JAVa JaVa I love JAVA you hate Java");
        /**
         *  查詢所有的Java，結果是：
         *  java
         *  Java
         *  JAVa
         *  JaVa
         *  JAVA
         *  Java
         */
        while (matcher.find()) {
            pri(matcher.group());
        }
    }

    public static void pri(Object object){
        System.out.println(object);
    }
}
 

3、替換成大寫

package com.wy.regular;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class RegularTest {

    public static void main(String[] args) {
        /**
         * 字串的替換 replacement
         * 使用compile(String regex, int flags)方法
         * CASE_INSENSITIVE 大小寫不敏感，忽略大小寫
         */
        Pattern pattern = Pattern.compile("java", Pattern.CASE_INSENSITIVE);
        Matcher matcher = pattern.matcher("java Java JAVa JaVa I love JAVA you hate Java");
        // 替換所有的Java為大寫
        pri(matcher.replaceAll("JAVA"));// 列印結果：JAVA JAVA JAVA JAVA I love JAVA you hate JAVA
    }

    public static void pri(Object object){
        System.out.println(object);
    }
}
 

4、單數個替換為大寫，雙數個替換為小寫

package com.wy.regular;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class RegularTest {

    public static void main(String[] args) {
        /**
         * 字串的替換 replacement
         * 使用compile(String regex, int flags)方法
         * CASE_INSENSITIVE 大小寫不敏感，忽略大小寫
         */
        Pattern pattern = Pattern.compile("java", Pattern.CASE_INSENSITIVE);
        Matcher matcher = pattern.matcher("java Java JAVa JaVa I love JAVA you hate Java tail");
        // 單數個替換為大寫，雙數個替換為小寫
        StringBuffer buffer = new StringBuffer();
        int i = 0;
        while (matcher.find()) {
            i++;
            if (i%2==0) {
                matcher.appendReplacement(buffer, "java");
            } else{
                matcher.appendReplacement(buffer, "JAVA");
            }
        }
        pri(buffer);// 結果：JAVA java JAVA java I love JAVA you hate java，沒有結尾的tail
        matcher.appendTail(buffer);// 新增最後的字串
        pri(buffer);// 結果：JAVA java JAVA java I love JAVA you hate java tail
    }

    public static void pri(Object object){
        System.out.println(object);
    }
}