几个java工具函数

package jing.tools;

import java.util.*;
import java.text.*; //日期处理用到的包
import java.util.regex.*;
import java.lang.*;

/**
*

Title: 常用基础函数

*

Description: 以下全部是静态函数

*

Copyright: Copyright (c) 2005

* “@deprecated Method 方法名 is deprecated” 在方法的注释里加上此注释，表示此方法以后版本不再被支持。
* 文件注释只能写在import后,类定义前才能在javadoc中出现文件的注释
* @author 欧朝敬 QQ:35712069
* @version 1.0
*/
public class BaseFunction {
public BaseFunction() {

}

/**
* 拼合一维数组为字符串。
* 拆分字串按指定字符分解到一维数组使用String类的split(String regex)
* @param param String[] 数组
* @param spilt String 字符串之单的分离符
* @return String
*/
public static String arrayToString(String[] param, String spilt) {
String rentunstring;
StringBuffer tempstr = new StringBuffer();
int len = param.length;
for (int i = 0; i < len - 1; i++) {
tempstr.append(param[i]);
tempstr.append(spilt);
}
tempstr.append(param[len - 1]);
rentunstring = tempstr.toString();
return rentunstring;
}

/**
* 产生在start和end之间的num个随机整数，返回值存在HashMap中。
* 示例
* HashMap hm=BaseFunction.random(1,100,5);
* Set set=hm.keySet();
* Iterator it=set.iterator();
* while(it.hasNext()){
* System.out.println(hm.get(it.next()));
* }
* @param start int 起始点
* @param end int 结束点
* @param num int 生成个数
* @return HashMap
*/
public static HashMap random(int start, int end, int num) {
HashMap hashMap = new HashMap();
for (int i = 0; i < num; i++) {
double sru = Math.random() * end;
int tag = Math.round((float) sru);
if (tag < start) {
i--;
} else {
hashMap.put(new Integer(i), new Integer(tag));
}
}
return hashMap;
}


/**
* 获取当前时间，返回时间格式(如果调用参数为true时返回yyyy-MM-dd HH:mm:ss
* ，否则为false时返回yyyy-MM-DD不带日期格式)
* @param time boolean
* @return String
* @throws Exception
*/
public static String getNowTime(boolean time) throws java.lang.Exception {
Date now = new Date();
String format = "";
//yyyy-MM-dd HH:mm:ss:S 年月日时分秒毫杪
if (time) {
format = "yyyy-MM-dd HH:mm:ss";
} else {
format = "yyyy-MM-dd";
}
SimpleDateFormat sdf = new SimpleDateFormat(format);
String nowtime = sdf.format(now);
return nowtime;
}

/**
* 将HashMap内容转入数组，
* 示例
* HashMap hashMap = new HashMap();
* hashMap.put("ka", "bb");
* hashMap.put("kb", "cc");
* hashMap.put("jk", "fdsaf");
* hashMap.put("ak", "kkkkk");
* Object[] obj = BaseFunction.hashMapToArray(hashMap);
* for (int i = 0; i < obj.length; i++) {
* System.out.println(obj);
* }
* @param param HashMap
* @return Object[]
*/
public static Object[] hashMapToArray(HashMap param) {
int size = param.size();
if (param == null || param.size() == 0) {
return null;
}
Object[] obj = new Object[size];
Set set = param.keySet();
Iterator ite = set.iterator();
for (int i = 0; ite.hasNext(); i++) {
obj = param.get(ite.next());
}
return obj;
}

/**
* 日期转字符串
* 示例：dateToString(stringToDate("2005-5-2 0:0:10"));
* @param date Date
* @return String
* 返回字符串格式为“yyyy年MM月dd日 HH时mm分ss秒”或“yyyy年MM月dd日”
* 根据输入的日期是否含有时间来确定输出格式
*/
public static String dateToString(Date date) {
Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("GMT+8"),
Locale.CHINA);
calendar.clear();
calendar.setTimeInMillis(date.getTime());
String format = "";

/* if (calendar.get(Calendar.MILLISECOND) == 0 &&
calendar.get(Calendar.SECOND) == 0 &&
calendar.get(Calendar.SECOND) == calendar.get(Calendar.MINUTE) &&
calendar.get(Calendar.MINUTE) == calendar.get(Calendar.HOUR)) {
format = "yyyy'年'MM'月'dd'日'";
} else {
format = "yyyy'年'MM'月'dd'日' HH'时'mm'分'ss'秒'";
}
*/
format = "yyyy'年'MM'月'dd'日' HH'时'mm'分'ss'秒'";
String return_string = "";
SimpleDateFormat sdf = new SimpleDateFormat(format);
//yyyy-MM-dd HH:mm:ss:S 年月日时分秒毫杪
return_string = sdf.format(date);
return return_string;
}

/**
* 字符串转日期
* 示例:stringToDate("2005-5-2 0:0:10");
* @param str String
* 输入字符串日期可用三种格式
* yyyy-MM-dd HH:mm:ss完整式
* yyyy-MM-dd HH:mm不含秒
* yyyy-MM-dd只有日期不含时间
* @return Date
* @throws Exception
*/
public static Date stringToDate(String str) throws Exception {
Date return_date = null;
String format = "";
if (str.length() > 13) {
format = "yyyy-MM-dd HH:mm:ss";
} else if (str.length() > 10) {
format = "yyyy-MM-dd HH:mm";
} else {
format = "yyyy-MM-dd";
}
try {
SimpleDateFormat sdf = new SimpleDateFormat(format);
return_date = sdf.parse(str);
} catch (ParseException e) {
throw new Exception(
"输入字符串的格式出错(格式为yyyy-MM-dd/yyyy-MM-dd HH:mm/yyyy-MM-dd HH:mm:ss)：" +
e.getMessage());
}
return return_date;
}

/**
* 连续产生指定个数的字符串
* @param str String
* @param count int
* @return String
*/
public static String continuousMakeString(String str, int count) {
StringBuffer sb = new StringBuffer();
for (int i = 0; i < count; i++) {
sb.append(str);
}
return (sb.toString());
}

/**
* 将字符串开头的所有空格替换成指定的字符
* 在JSP中经常用到把字符串开头的n个空格替换成n个 字符
* 就可以使用此函数调用示例
* replaceStartsWithSpace(" 中国 湖南 长沙"," ");结果为“  中国 湖南 长沙”
* @param str String
* @param sub String
* @return String
*/
public static String replaceStartsWithSpace(String str, String sub) {
String returnStr = "";
String regEx = "//S"; //非空格字符
Pattern pattern = Pattern.compile(regEx);
Matcher matcher = pattern.matcher(str);
matcher.find();
int start = matcher.start(); //非空格开始的位置
for (int i = 0; i < start; i++) {
returnStr = returnStr + sub;
}
returnStr = returnStr + str.substring(start);
return returnStr;
}

/**
* 查找指定的元素是否存在于元素数组中
* 使用Object支持各种对象数组
* 示例
* String[] des = {"ada", "ss", "dd","aa"};
* System.out.println(BaseFunction.contains(str, "adfab"));
* @param objArray Object[]
* @param value Object
* @return int 如果查到则返回第一次在数组中出现的下标值，查不到则返回值为-1
*/
public static int contains(Object[] objArray, Object value) {
int j = -1;
for (int i = 0; i < objArray.length; i++) {
if (objArray.equals(value)) { //查到则返回下标
j = i;
break;
}
}
return j;
}

/**
* 字符串数组中是否包含指定的字符串。
* @param strings 字符串数组
* @param string 字符串
* @param caseSensitive 是否大小写敏感(true区分大小写,false不区分大小写)
* @return 包含时返回true，否则返回false
* @since 0.4
*/
public static boolean contains(String[] strings, String string,
boolean caseSensitive) {
for (int i = 0; i < strings.length; i++) {
if (caseSensitive == true) {
if (strings.equals(string)) {
return true;
}
} else {
if (strings.equalsIgnoreCase(string)) {
return true;
}
}
}
return false;
}

/**
* 数组拷贝,建议使用System.arraycopy()速度更快,把source数据内容拷贝到destination中
* 使用Object则支持多种对象数组
* 示例
* String[] des = {"ada", "ss", "dd","aa"};
* String[] src = new String[8];
* BaseFunction.copy(des, src);
* @param source Object[]
* @param destination Object[]
*/
public static void copy(Object[] source, Object[] destination) {
if (destination == null || source == null) {
throw new java.lang.NullPointerException("数组没有初始化！");
}
if (destination.length < source.length) {
throw new java.lang.ArrayIndexOutOfBoundsException("两数组长度不相等!");
}
for (int i = 0; i < source.length; i++) {
destination = source;
}
}

/**
* 去除数组中的重复元素，调用示例
* String[] src = {"dafdfad", "asdfasdf", "dafdfad", "adfasdf", "dafdfad","dafdfad"};
* Object[] test =BaseFunction.wipeOffRepeat(src);
* @param objArray Object[]
* @return Object[]
*/
public static Object[] wipeOffRepeat(Object[] objArray) {
Object[] obj = null;
ArrayList list = new ArrayList();
for (int i = 0; i < objArray.length; i++) {
list.add(objArray);
}
//去除list中的重复对象
HashSet h = new HashSet(list);
list.clear();
list.addAll(h);
obj = list.toArray();
return obj;
}

/**
* 四舍五入
* @param param double 要进行四舍五入的值
* @param num int 保留的小数位数
* @return double
*/
public static double round(double param, int num) {
NumberFormat nf = NumberFormat.getNumberInstance();
nf.setMaximumFractionDigits(num);
double returndouble = Double.parseDouble(nf.format(param));
return returndouble;
}

/**
* 主函数做测试用
* @param args String[]
* @throws Exception
*/
public static void main(String[] args) throws Exception {
/* System.out.println(BaseFunction.dateToString(stringToDate(
"2005-5-2 0:0:10")));
System.out.println(BaseFunction.getTime(true));
System.out.println(BaseFunction.continuousMakeString(" ", 10));
System.out.println(BaseFunction.replaceStartsSpace(
" fadsfas dfsd", " "));
*/
/* HashMap hm=BaseFunction.random(1,100,5);
Set set=hm.keySet();
Iterator it=set.iterator();
while(it.hasNext()){
System.out.println(hm.get(it.next()));
}
*/
//System.out.println(BaseFunction.replaceStartsWithSpace(" 中国 湖南 长沙"," "));
System.out.println(BaseFunction.round(0.25689,2));
}
}