一些Java工具类

 

package com.commons;import java.math.BigInteger;import java.security.MessageDigest;public class Utils {    /**     * 把字符串转换成utf-8格式(Excel导出时,文件名调用)     *      * @param s     * @return     */    public static String toUtf8String(String s) {StringBuffer sb = new StringBuffer();for (int i = 0; i < s.length(); i++) {    char c = s.charAt(i);    if (c >= 0 && c <= 255) {sb.append(c);    } else {byte[] b;try {    b = Character.toString(c).getBytes("utf-8");} catch (Exception ex) {    b = new byte[0];}for (int j = 0; j < b.length; j++) {    int k = b[j];    if (k < 0)k += 256;    sb.append("%" + Integer.toHexString(k).toUpperCase());}    }}return sb.toString();    }    /*     * 将字符串第一个字母大写     */    public static String firstCharToUpperCase(String s) {return s == null || s.equals("") ? s : s.substring(0, 1).toUpperCase()+ s.substring(1);    }    /**     * MD5签名信息     * */    public static String MessageDigest(String p_plain) {try {    MessageDigest w_md = MessageDigest.getInstance("MD5");    w_md.update(p_plain.getBytes());    byte[] w_digests = w_md.digest();    return new BigInteger(1, w_digests).toString(16);} catch (Exception p_e) {    p_e.printStackTrace();}return p_plain;    }}