java常用工具方法
/**
* 将字节数组转换成字符串
* @param array 字节数组
* @return String
*/
public static String byte2str(byte[] array){
StringBuffer hexstr = new StringBuffer();
String shaHex = "";
for(int i=0;i<array.length;i++){
shaHex = Integer.toHexString(array[i] & 0xFF);
if(shaHex.length()<2){
hexstr.append(0);
}
hexstr.append(shaHex);
}
return hexstr.toString();
}
/**
* 判断字符串非空
* @param str 字符串
* @return boolean
*/
private static boolean hasLength(String str){
return str!=null && !"".equals(str.trim());
}
/**
* 判断字符串为空
* @param str 字符串
* @return boolean
*/
private static boolean hasLengths(String str){
return !hasLength(str);
}
/**
* 得到本周周一的日期
* @return yyyy-MM-dd
*/
public static String getMondayOfThisWeek(){
DateFormat df = new SimpleDateFormat("yyyy-MM-dd");
Calendar c = Calendar.getInstance();
//得到今天星期几
int dayOfWeek = c.get(Calendar.DAY_OF_WEEK)-1;
//对星期天特殊对待
if(dayOfWeek == 0)
dayOfWeek = 7;
//假如今天是星期四,往前推3天就是星期一,即(4-1)
c.add(Calendar.DATE, -(dayOfWeek - 1));
return df.format(c.getTime());
}