qt/jdc/chatServer/trunk/src/main/java/com/jsjty/util/StringUtil.java

package com.jsjty.util;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.sql.Timestamp;
import java.text.SimpleDateFormat;
import java.util.Collection;
import java.util.Date;
import java.util.Map;
import java.util.UUID;

import javax.servlet.http.HttpServletRequest;

public class StringUtil {

    private final static SimpleDateFormat dateformat = new SimpleDateFormat("yyyy-MM-dd kk:mm:ss");

    public static String formatDate(Date date) {

        return dateformat.format(date);
    }

    public static String formatTimestamp(Timestamp timestamp) {

        return dateformat.format(timestamp);
    }

    /**
     * 获取错误日志详细信息
     * 
     * @param t
     * @return String
     */
    public static String getTrace(Throwable t) {
        StringWriter stringWriter = new StringWriter();
        PrintWriter writer = new PrintWriter(stringWriter);
        t.printStackTrace(writer);
        StringBuffer buffer = stringWriter.getBuffer();
        return buffer.toString();
    }

    public static String[] str2Array(String params) {

        if (params != null) { return params.split(","); }
        return null;
    }

    /**
     * 对文件流输出下载的中文文件名进行编码 屏蔽各种浏览器版本的差异性
     */
    public static String encodeChineseDownloadFileName(HttpServletRequest request, String pFileName) {
        String agent = request.getHeader("USER-AGENT");
        try {
            if (null != agent && -1 != agent.indexOf("MSIE")) {
                pFileName = URLEncoder.encode(pFileName, "utf-8");
            }
            else {
                pFileName = new String(pFileName.getBytes("utf-8"), "iso8859-1");
            }
        }
        catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        return pFileName;
    }

    /**
     * 判断对象是否Empty(null或元素为0)<br>
     * 实用于对如下对象做判断:String Collection及其子类 Map及其子类
     *
     * @param pObj
     *            待检查对象
     * @return boolean 返回的布尔值
     */
    @SuppressWarnings("rawtypes")
    public static boolean isEmpty(Object pObj) {
        if (pObj == null) return true;
        if (pObj == "") return true;
        if (pObj instanceof String) {
            if (((String) pObj).length() == 0) { return true; }
        }
        else if (pObj instanceof Collection) {
            if (((Collection) pObj).size() == 0) { return true; }
        }
        else if (pObj instanceof Map) {
            if (((Map) pObj).size() == 0) { return true; }
        }
        return false;
    }

    /**
     * 判断对象是否为NotEmpty(!null或元素>0)<br>
     * 实用于对如下对象做判断:String Collection及其子类 Map及其子类
     *
     * @param pObj
     *            待检查对象
     * @return boolean 返回的布尔值
     */
    @SuppressWarnings("rawtypes")
    public static boolean isNotEmpty(Object pObj) {
        if (pObj == null) return false;
        if (pObj == "") return false;
        if (pObj instanceof String) {
            if (((String) pObj).length() == 0) { return false; }
        }
        else if (pObj instanceof Collection) {
            if (((Collection) pObj).size() == 0) { return false; }
        }
        else if (pObj instanceof Map) {
            if (((Map) pObj).size() == 0) { return false; }
        }
        return true;
    }

    public static String getUUID() {
        return UUID.randomUUID().toString().replace("-", "");
    }

    public static String parseByte2HexStr(byte buf[]) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < buf.length; i++) {
            String hex = Integer.toHexString(buf[i] & 0xFF);
            if (hex.length() == 1) {
                hex = '0' + hex;
            }
            sb.append(hex.toUpperCase());
        }
        return sb.toString();
    }

    /**
     * 把16进制字符串转换成字节数组
     * 
     * @param hexString
     * @return byte[]
     */
    public static byte[] hexStringToByte(String hex) {
        int len = (hex.length() / 2);
        byte[] result = new byte[len];
        char[] achar = hex.toCharArray();
        for (int i = 0; i < len; i++) {
            int pos = i * 2;
            result[i] = (byte) (toByte(achar[pos]) << 4 | toByte(achar[pos + 1]));
        }
        return result;
    }

    private static int toByte(char c) {
        byte b = (byte) "0123456789ABCDEF".indexOf(c);
        return b;
    }
}