java日期操作

/**
* Program   :   DateHelp.java
* Author    :   Jsm
* Create    :   2009-04-30
*
* Copyright 1995-1998,2000 by Global Data Solutions,
* All rights reserved.
*
* This software is the confidential and proprietary information
* of Global Data Solutions. ("Confidential Information").  You
* shall not disclose such Confidential Information and shall use
* it only in accordance with the terms of the license agreement
* you entered into with Global Data Solutions.
*
*/
package com.lingteng.date;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.ResourceBundle;
import java.util.Locale;
import java.util.Calendar;

import org.apache.log4j.Logger;

/**
* Date Tools
*
* @Author: Jsm
* @Create: 2009-04-30
* @Email: jsm_sun@sina.com
*
*/
public class DateHelp {

private static Logger log = Logger.getLogger(DateHelp.class);
private static ResourceBundle resource = ResourceBundle.getBundle("resources.date", Locale.CHINA);

private DateHelp() {
}

/** 获取日期格式 yyyy/MM/dd */
public static final int PATTERN_1 = 1;
/** 获取日期格式 yyyy/MM/dd HH:mm:ss */
public static final int PATTERN_2 = 2;
/** 获取日期格式 yyyy/MM/dd HH:mm:ss:sss */
public static final int PATTERN_3 = 3;
/** 获取日期格式 yyyy-MM-dd */
public static final int PATTERN_4 = 4;
/** 获取日期格式 yyyy-MM-dd HH:mm:ss */
public static final int PATTERN_5 = 5;
/** 获取日期格式 yyyy-MM-dd HH:mm:ss:sss */
public static final int PATTERN_6 = 6;
/** 获取年 */
public static final int PATTERN_7 = 7;
/** 获取年终的月份 */
public static final int PATTERN_8 = 8;
/** 获取年终的周数 */
public static final int PATTERN_9 = 9;
/** 获取月份中的周数 */
public static final int PATTERN_10 = 10;
/** 获取年中的天数 */
public static final int PATTERN_11 = 11;
/** 获取月份中的天数 */
public static final int PATTERN_12 = 12;
/** 获取月份中的星期 */
public static final int PATTERN_13 = 13;
/** 获取星期中的天数 */
public static final int PATTERN_14 = 14;
/** 获取一天中的小时数(0-23) */
public static final int PATTERN_15 = 15;
/** 获取一天中的小时数(1-24) */
public static final int PATTERN_16 = 16;
/** 获取am/pm 中的小时数(0-11) */
public static final int PATTERN_17 = 17;
/** 获取am/pm 中的小时数(1-11) */
public static final int PATTERN_18 = 18;
/** 获取小时中的分钟数 */
public static final int PATTERN_19 = 19;
/** 获取分钟中的秒数 */
public static final int PATTERN_20 = 20;
/** 获取毫秒数 */
public static final int PATTERN_21 = 21;

/**
*
* @param date:
*            格式化的日期, 如果日期为null, 则代表当前日期
* @param pattern:
*            格式化的日期模式
* @return: 返回字符串日期的格式.如果发生异常或格式不存在返回null
*/
public static String getStringDate(Date date, int pattern) {
String strDate = null;
SimpleDateFormat sdf = new SimpleDateFormat();
String errMsg = null;

if (date == null)
date = new Date();

try {
switch (pattern) {
case PATTERN_1:
sdf.applyPattern("yyyy/MM/dd");
break;
case PATTERN_2:
sdf.applyPattern("yyyy/MM/dd HH:mm:ss");
break;
case PATTERN_3:
sdf.applyPattern("yyyy/MM/dd HH:mm:ss:sss");
break;
case PATTERN_4:
sdf.applyPattern("yyyy-MM-dd");
break;
case PATTERN_5:
sdf.applyPattern("yyyy-MM-dd HH:mm:ss");
break;
case PATTERN_6:
sdf.applyPattern("yyyy-MM-dd HH:mm:ss:sss");
break;
case PATTERN_7:
sdf.applyPattern("y");
break;
case PATTERN_8:
sdf.applyPattern("M");
break;
case PATTERN_9:
sdf.applyPattern("w");
break;
case PATTERN_10:
sdf.applyPattern("W");
break;
case PATTERN_11:
sdf.applyPattern("D");
break;
case PATTERN_12:
sdf.applyPattern("d");
strDate = sdf.format(date);
break;
case PATTERN_13:
sdf.applyPattern("F");
break;
case PATTERN_14:
sdf.applyPattern("E");
break;
case PATTERN_15:
sdf.applyPattern("H");
break;
case PATTERN_16:
sdf.applyPattern("k");
break;
case PATTERN_17:
sdf.applyPattern("K");
break;
case PATTERN_18:
sdf.applyPattern("h");
break;
case PATTERN_19:
sdf.applyPattern("m");
break;
case PATTERN_20:
sdf.applyPattern("s");
break;
case PATTERN_21:
sdf.applyPattern("S");
break;
default:
errMsg = resource.getString("format_not_exist");
log.info(errMsg);
break;
}

strDate = sdf.format(date);

sdf = null;
} catch (Exception e) {
strDate = null;
errMsg = resource.getString("date_convert_string_error");
log.info(errMsg + "-->>" + e.getMessage());
}

return strDate;
}

/**
*
* @param pattern:
*            转换成当前日期的格式
* @return: 返回字符串当前日期格式
*/
public static String getStringNowDate(int pattern) {
return getStringDate(null, pattern);
}

/**
*
* @param date:
* 格式化的日期, 如果日期为null, 则代表当前日期
* @param pattern:
* 格式化日期的字符串模式, 例如:yyyy/MM/dd
* @return  返回字符串日期的格式.如果发生异常或格式不存在返回null
*/
public static String getStringDate(Date date, String pattern){
String errMsg = "";
try {
SimpleDateFormat sdf = new SimpleDateFormat();
sdf.applyPattern(pattern);
if(date == null)
date = new Date();

String strDate = sdf.format(date);

sdf = null;
return strDate;
} catch (Exception e) {
errMsg = resource.getString("date_convert_string_error");
log.info(errMsg + "-->>" +e.getMessage());
return null;
}
}

/**
*
* @param pattern:
* 格式化日期的字符串模式, 例如:yyyy/MM/dd
* @return 返回字符串日期的格式.如果发生异常或格式不存在返回null
*/
public static String getStringNowDate(String pattern){
return getStringDate(null, pattern);
}


/**
*
* @param strDate:
* 字符串日期
* @param pattern:
* 转换的格式, 字符串日期要与转换的格式相匹配
* @return 返回把字符串日期转换成日期, 如果发生异常返回null
*/
public static Date getDate(String strDate, String pattern) throws ParseException {
String errMsg = "";
try {
SimpleDateFormat sdf = new SimpleDateFormat();
sdf.applyPattern(pattern);
Date date = sdf.parse(strDate);

sdf = null;
return date;
} catch (Exception e) {
errMsg = resource.getString("string_convert_date_error");
log.info(errMsg + "-->>" + e.getMessage());
}

return null;
}

/**
*
* @param date:
* 字符串日期
* @param pattern:
* 字符串格式,字符串格式与日期匹配
* @return 返回日期加一天后的日期
*/
public static Date dateAddA(String strDate, String pattern) throws ParseException {
Date date = getDate(strDate, pattern);
if(date == null){
throw new ParseException("", 1);
}

return dateAddSub(date, '+');
}

/**
*
* @param date:
* 日期
* @return 返回日期加一天后的日期
* @throws Exception
*/
public static Date dateAddA(Date date) throws Exception {
if(date == null){
throw new Exception("");
}

return dateAddSub(date, '+');
}

/**
*
* @param date:
* 字符串日期
* @param pattern:
* 字符串格式,字符串格式与日期匹配
* @return 返回日期减一天后的日期
*/
public static Date dateSubA(String strDate, String pattern) throws ParseException {
Date date = getDate(strDate, pattern);
if(date == null){
throw new ParseException("", 1);
}

return dateAddSub(date, '-');
}

/**
*
* @param date:
* 日期
* @return 返回日期减一天后的日期
* @throws Exception
*/
public static Date dateSubA(Date date) throws Exception {
if(date == null){
throw new Exception("");
}

return dateAddSub(date, '-');
}

private static Date dateAddSub(Date date, char ch){
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);

if(ch == '+'){
calendar.set(Calendar.DAY_OF_YEAR, calendar.get(Calendar.DAY_OF_YEAR) + 1);
}else if(ch == '-'){
calendar.set(Calendar.DAY_OF_YEAR, calendar.get(Calendar.DAY_OF_YEAR) - 1);
}

return calendar.getTime();
}


public static void main(String[] args) throws Exception {
System.out.println(getStringDate(dateAddA(new Date()), DateHelp.PATTERN_1));
}

}

牛逼啊~~

让人看的很头疼。。这个排版。。建议。。把代码写在代码块上。。

/** 获取日期格式 yyyy/MM/dd */
public static final int PATTERN_1 = 1;
/** 获取日期格式 yyyy/MM/dd HH:mm:ss */
public static final int PATTERN_2 = 2;
/** 获取日期格式 yyyy/MM/dd HH:mm:ss:sss */
public static final int PATTERN_3 = 3;
/** 获取日期格式 yyyy-MM-dd */
public static final int PATTERN_4 = 4;
/** 获取日期格式 yyyy-MM-dd HH:mm:ss */
public static final int PATTERN_5 = 5;
/** 获取日期格式 yyyy-MM-dd HH:mm:ss:sss */
public static final int PATTERN_6 = 6;
/** 获取年 */
public static final int PATTERN_7 = 7;
/** 获取年终的月份 */
public static final int PATTERN_8 = 8;
/** 获取年终的周数 */
public static final int PATTERN_9 = 9;
/** 获取月份中的周数 */
public static final int PATTERN_10 = 10;
/** 获取年中的天数 */
public static final int PATTERN_11 = 11;
/** 获取月份中的天数 */
public static final int PATTERN_12 = 12;
/** 获取月份中的星期 */
public static final int PATTERN_13 = 13;
/** 获取星期中的天数 */
public static final int PATTERN_14 = 14;
/** 获取一天中的小时数(0-23) */
public static final int PATTERN_15 = 15;
/** 获取一天中的小时数(1-24) */
public static final int PATTERN_16 = 16;
/** 获取am/pm 中的小时数(0-11) */
public static final int PATTERN_17 = 17;
/** 获取am/pm 中的小时数(1-11) */
public static final int PATTERN_18 = 18;
/** 获取小时中的分钟数 */
public static final int PATTERN_19 = 19;
/** 获取分钟中的秒数 */
public static final int PATTERN_20 = 20;
/** 获取毫秒数 */
public static final int PATTERN_21 = 21;

/**
*
* @param date:
*            格式化的日期, 如果日期为null, 则代表当前日期
* @param pattern:
*            格式化的日期模式
* @return: 返回字符串日期的格式.如果发生异常或格式不存在返回null
*/
public static String getStringDate(Date date, int pattern) {
String strDate = null;
SimpleDateFormat sdf = new SimpleDateFormat();
String errMsg = null;

if (date == null)
date = new Date();

try {
switch (pattern) {
case PATTERN_1:
sdf.applyPattern("yyyy/MM/dd");
strDate = sdf.format(date);
break;
case PATTERN_2:
sdf.applyPattern("yyyy/MM/dd HH:mm:ss");
strDate = sdf.format(date);
break;
case PATTERN_3:
sdf.applyPattern("yyyy/MM/dd HH:mm:ss:sss");
strDate = sdf.format(date);
break;
case PATTERN_4:
sdf.applyPattern("yyyy-MM-dd");
strDate = sdf.format(date);
break;
case PATTERN_5:
sdf.applyPattern("yyyy-MM-dd HH:mm:ss");
strDate = sdf.format(date);
break;
case PATTERN_6:
sdf.applyPattern("yyyy-MM-dd HH:mm:ss:sss");
strDate = sdf.format(date);
break;
case PATTERN_7:
sdf.applyPattern("y");
strDate = sdf.format(date);
break;
case PATTERN_8:
sdf.applyPattern("M");
strDate = sdf.format(date);
break;
case PATTERN_9:
sdf.applyPattern("w");
strDate = sdf.format(date);
break;
case PATTERN_10:
sdf.applyPattern("W");
strDate = sdf.format(date);
break;
case PATTERN_11:
sdf.applyPattern("D");
strDate = sdf.format(date);
break;
case PATTERN_12:
sdf.applyPattern("d");
strDate = sdf.format(date);
break;
case PATTERN_13:
sdf.applyPattern("F");
strDate = sdf.format(date);
break;
case PATTERN_14:
sdf.applyPattern("E");
strDate = sdf.format(date);
break;
case PATTERN_15:
sdf.applyPattern("H");
strDate = sdf.format(date);
break;
case PATTERN_16:
sdf.applyPattern("k");
strDate = sdf.format(date);
break;
case PATTERN_17:
sdf.applyPattern("K");
strDate = sdf.format(date);
break;
case PATTERN_18:
sdf.applyPattern("h");
strDate = sdf.format(date);
break;
case PATTERN_19:
sdf.applyPattern("m");
strDate = sdf.format(date);
break;
case PATTERN_20:
sdf.applyPattern("s");
strDate = sdf.format(date);
break;
case PATTERN_21:
sdf.applyPattern("S");
strDate = sdf.format(date);
break;
default:
errMsg = resource.getString("format_not_exist");
log.info(errMsg);
break;
} 

这段代码是亮点啊~

代码过于冗余。