java 日期转化工具类和智能转化总结

/**
* Created by Administrator on 2017/5/11 0011.
* 日期转化工具类
*/
public class DateUtil {

public static final String Y_M_D = "yyyy-MM-dd";

public static final String Y_M_D_HM = "yyyy_MM_dd HH:mm";

public static final String Y_M_D_HMS = "yyyy-MM-dd HH:mm:ss";

public static final String YMD = "yyyyMMdd";

public static final String YMDHM = "yyyyMMddHHmm";

public static final String YMDHMS = "yyyyMMddHHmmss";

public static final String ymd = "yyyy/MM/dd";

public static final String ymd_HM = "yyyy/MM/dd HH:mm";

public static final String ymd_HMS = "yyyy/MM/dd HH:mm:ss";

/**
* 智能转换日期
*
* @param date
* @return
*/
public static String smartFormat(Date date) {
String dateStr = null;
if (date == null) {
dateStr = "";
} else {
try {
dateStr = formatDate(date, Y_M_D_HMS);
// 时分秒
if (dateStr.endsWith(" 00:00:00")) {
dateStr = dateStr.substring(0, 10);
}
// 时分
else if (dateStr.endsWith("00:00")) {
dateStr = dateStr.substring(0, 19);
}
// 秒
else if (dateStr.endsWith(":00")) {
dateStr = dateStr.substring(0, 19);
}
} catch (Exception ex) {
throw new IllegalArgumentException("转换日期失败: " + ex.getMessage(), ex);
}
}
return dateStr;
}

/**
* 智能转换日期
*
* @param text
* @return
*/
public static Date smartFormat(String text) {
Date date = null;
try {
if (text == null || text.length() == 0) {
date = null;
} else if (text.length() == 10) {
date = formatStringToDate(text, Y_M_D);
} else if (text.length() == 13) {
date = new Date(Long.parseLong(text));
} else if (text.length() == 16) {
date = formatStringToDate(text, Y_M_D_HM);
} else if (text.length() == 19) {
date = formatStringToDate(text, Y_M_D_HMS);
} else {
throw new IllegalArgumentException("日期长度不符合要求!");
}
} catch (Exception e) {
throw new IllegalArgumentException("日期转换失败!");
}
return date;
}

/**
* 获取当前日期
*
* @param format
* @return
* @throws Exception
*/
public static String getNow(String format) throws Exception {
return formatDate(new Date(), format);
}

/**
* 格式化日期格式
*
* @param argDate
* @param argFormat
* @return 格式化后的日期字符串
*/
public static String formatDate(Date argDate, String argFormat) throws Exception {
if (argDate == null) {
throw new Exception("参数[日期]不能为空!");
}
if (StringUtils.isEmpty(argFormat)) {
argFormat = Y_M_D;
}
SimpleDateFormat sdfFrom = new SimpleDateFormat(argFormat);
return sdfFrom.format(argDate).toString();
}

/**
* 把字符串格式化日期
* @param argDateStr
* @param argFormat
* @return
* @throws Exception
*/
public static Date formatStringToDate(String argDateStr,String argFormat) throws Exception{
if (argDateStr == null || argDateStr.trim().length()<1){
throw new Exception("日期不能为空！");
}
String strFormat = null;
if (StringUtils.isEmpty(argFormat)){
strFormat=Y_M_D;
if (argDateStr.length()>16){
strFormat =Y_M_D_HMS;
}else if (argDateStr.length()>10){
strFormat=Y_M_D_HM;
}
}
SimpleDateFormat simpleDateFormat = new SimpleDateFormat(strFormat);
//严格模式
simpleDateFormat.setLenient(false);//这个功能是不能把1996-13-1转换为1997-1-3
return simpleDateFormat.parse(argDateStr);
}

}

/**
*
* 智能日期转换
*
*/
@SuppressWarnings("serial")
public class SmartDateFormat extends SimpleDateFormat {

//parse()返回的是一个Date类型数据，format返回的是一个StringBuffer类型的数据
//SimpleDateFormat中的parse方法可以
//把String型的字符串转换成特定格式的date类型

@Override
public StringBuffer format(Date date, StringBuffer toAppendTo, FieldPosition pos) {
return new StringBuffer(DateUtil.smartFormat(date));
}

//SimpleDateFormat中的format方法可以
//把Date型的字符串转换成特定格式的String类型

@Override
public Date parse(String text) throws ParseException {
return DateUtil.smartFormat(text);
}
}