java判断是否为数字

import org.apache.commons.lang3.StringUtils;

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

public class NumberUtils {
    private static Pattern integerPattern = Pattern.compile("^[-\\+]?\\d+$");
    private static Pattern doublePattern = Pattern.compile("^[-\\+]?\\d+\\.\\d+$");
    private static Pattern numberPattern = Pattern.compile("^[-\\+]?\\d+(\\.?\\d+)?$");

    /**
     *
     * @param in
     * @return
     */
    public static boolean isInteger(String in) {
        if (StringUtils.isBlank(in)) {
            return false;
        }

        Matcher matcher = integerPattern.matcher(in);

        return matcher.find();
    }

    /**
     *
     * @param in
     * @return
     */
    public static boolean isDouble(String in) {
        if (StringUtils.isBlank(in)) {
            return false;
        }

        Matcher matcher = doublePattern.matcher(in);

        return matcher.find();
    }

    /**
     *
     * @param in
     * @return
     */
    public static boolean isNumber(String in) {
        if (StringUtils.isBlank(in)) {
            return false;
        }

        Matcher matcher = numberPattern.matcher(in);

        return matcher.find();
    }

}