http://deerchao.net/tutorials/regex/regex.htm#lookaround

代码展现

package test;

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

public class RegexUtil {

    public static void main(String[] args) {

        /*** * .*(?=>) 600 * * (?<=>=)+.*(?=and) 2 * * (?<=\\()+.*(?=!=) int * 其中：\\为转义字符 * (?<=!=)+.*(?=or) int * * (?<=or)+.*(?=<=) 2 * * (?<=<=)+.*(?=\\)) 600 */

    String input = "600>=2 and (int != int or 2 <= 600)";

    String regex = "(?<=<=)+.*(?=\\))";

    System.out.println(Match(input,regex));

    }

    /** * * 正则表达式辅助类 * * @param input 字符串 * @param regex 正则表达式 * @return 正则表达式匹配结果 */
public static String Match(String input,String regex) {

    Pattern praiseCompile = Pattern.compile(regex);

    Matcher praiseMatcher = praiseCompile.matcher(input);

    if (praiseMatcher.find()) {

        return praiseMatcher.group(0).trim();

    }

    return null;

    }

}