JAVA常用操作语句----项目中的总结五
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- 数字的格式化
DecimalFormat df = new DecimalFormat(",###.00");
double aNumber = 33665448856.6568975;
String result = df.format(aNumber);
Sytem. out.println(result);
输出结果为：
33,665,448,856.66
- 分析字符串
StringTokenizer(String s) 构造一个分析器，使用默认分隔字符（空格，换行，回车，Tab，进纸符）
StringTokenizer(String s,String delim) delim是自己定义的分隔符
nextToken() 逐个获取字符串中的语言符号
boolean hasMoreTokens() 只要字符串还有语言符号将返回true，否则返回false
countTokens() 得到一共有多少个语言符号
- 数组的选择排序
public void ListNum(int[] a){
for(int k=0;k<a.length-1;k++){
int j=k;
int mini=a[k];
for(int i=k+1;i<a.length;i++){
if(a[k]>a[i]){
a[k]=a[i];
j=i;
}
}
a[j]=mini;
}
}
- MD5和一个可逆加密算法相接合的加密和解密程序
import java.security.MessageDigest;
/**
*先通过MD5加密之后，再来一次可逆的加密。
*顺序可以调整，可以选择先用可逆加密，然后再用MD5加密
*/
public class MD5andKL{
//MD5加码。32位
public static String MD5(String inStr) {
MessageDigest md5 = null;
try {
md5 = MessageDigest.getInstance("MD5");
} catch (Exception e) {
System.out.println(e.toString());
e.printStackTrace();
return "";
}
char[] charArray = inStr.toCharArray();
byte[] byteArray = new byte[charArray.length];
for (int i = 0; i < charArray.length; i++)
byteArray[i] = (byte) charArray[i];
byte[] md5Bytes = md5.digest(byteArray);
StringBuffer hexValue = new StringBuffer();
for (int i = 0; i < md5Bytes.length; i++) {
int val = ((int) md5Bytes[i]) & 0xff;
if (val < 16)
hexValue.append("0");
hexValue.append(Integer.toHexString(val));
}
return hexValue.toString();
}
//可逆的加密算法
public static String KL(String inStr){
//String s = new String(inStr);
char[] a = inStr.toCharArray();
for (int i = 0;i <a.length;i++) {
a[i] = (char)(a[i]^'t');
}
String s=new String(a);
return s;
}
//加密后解密
public static String JM(String inStr){
char[] a=inStr.toCharArray();
for (int i = 0;i <a.length;i++) {
a[i]= (char)(a[i]^'t');
}
String k=new String(a);
return k;
}
//测试主函数
public static void main (String args[]){
String s = new String("admin");
System.out.println("原始："+s);
System.out.println("MD5后："+MD5(s));
System.out.println("MD5后再加密："+KL(MD5(s)));
System.out.println("解密为MD5后的："+JM(KL(MD5(s))));
}
}
- 任意对象转化为JSON
- import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* 序列化对象为JSON格式 遵循JSON组织公布标准
*
* @date 2008/05/07
* @version 1.0.0
*/
public class Json {
/** Commons Logging instance. */
private static org.apache.commons.logging.Log log = org.apache.commons.logging.LogFactory.getLog(Json.class);
/**
* @param obj 任意对象
* @return String
*/
public static String object2json(Object obj) {
StringBuilder json = new StringBuilder();
if (obj == null) {
json.append("/"/"");
} else if (obj instanceof String || obj instanceof Integer || obj instanceof Float || obj instanceof Boolean
|| obj instanceof Short || obj instanceof Double || obj instanceof Long || obj instanceof BigDecimal
|| obj instanceof BigInteger || obj instanceof Byte) {
json.append("/"").append(string2json(obj.toString())).append("/"");
} else if (obj instanceof Object[]) {
json.append(array2json((Object[]) obj));
} else if (obj instanceof List) {
json.append(list2json((List<?>) obj));
} else if (obj instanceof Map) {
json.append(map2json((Map<?, ?>) obj));
} else if (obj instanceof Set) {
json.append(set2json((Set<?>) obj));
} else {
json.append(bean2json(obj));
}
return json.toString();
}
/**
* @param bean bean对象
* @return String
*/
public static String bean2json(Object bean) {
StringBuilder json = new StringBuilder();
json.append("{");
PropertyDescriptor[] props = null;
try {
props = Introspector.getBeanInfo(bean.getClass(), Object.class).getPropertyDescriptors();
} catch (IntrospectionException e) {
}
if (props != null) {
for (int i = 0; i < props.length; i++) {
try {
String name = object2json(props[i].getName());
String value = object2json(props[i].getReadMethod().invoke(bean));
json.append(name);
json.append(":");
json.append(value);
json.append(",");
} catch (Exception e) {
}
}
json.setCharAt(json.length() - 1, '}');
} else {
json.append("}");
}
return json.toString();
}
/**
* @param list list对象
* @return String
*/
public static String list2json(List<?> list) {
StringBuilder json = new StringBuilder();
json.append("[");
if (list != null && list.size() > 0) {
for (Object obj : list) {
json.append(object2json(obj));
json.append(",");
}
json.setCharAt(json.length() - 1, ']');
} else {
json.append("]");
}
return json.toString();
}
/**
* @param array 对象数组
* @return String
*/
public static String array2json(Object[] array) {
StringBuilder json = new StringBuilder();
json.append("[");
if (array != null && array.length > 0) {
for (Object obj : array) {
json.append(object2json(obj));
json.append(",");
}
json.setCharAt(json.length() - 1, ']');
} else {
json.append("]");
}
return json.toString();
}
/**
* @param map map对象
* @return String
*/
public static String map2json(Map<?, ?> map) {
StringBuilder json = new StringBuilder();
json.append("{");
if (map != null && map.size() > 0) {
for (Object key : map.keySet()) {
json.append(object2json(key));
json.append(":");
json.append(object2json(map.get(key)));
json.append(",");
}
json.setCharAt(json.length() - 1, '}');
} else {
json.append("}");
}
return json.toString();
}
/**
* @param set 集合对象
* @return String
*/
public static String set2json(Set<?> set) {
StringBuilder json = new StringBuilder();
json.append("[");
if (set != null && set.size() > 0) {
for (Object obj : set) {
json.append(object2json(obj));
json.append(",");
}
json.setCharAt(json.length() - 1, ']');
} else {
json.append("]");
}
return json.toString();
}
/**
* @param s 参数
* @return String
*/
public static String string2json(String s) {
if (s == null)
return "";
StringBuilder sb = new StringBuilder();
for (int i = 0; i < s.length(); i++) {
char ch = s.charAt(i);
switch (ch) {
case '"':
sb.append("///"");
break;
case '//':
sb.append("////");
break;
case '/b':
sb.append("//b");
break;
case '/f':
sb.append("//f");
break;
case '/n':
sb.append("//n");
break;
case '/r':
sb.append("//r");
break;
case '/t':
sb.append("//t");
break;
case '/':
sb.append("///");
break;
default:
if (ch >= '/u0000' && ch <= '/u001F') {
String ss = Integer.toHexString(ch);
sb.append("//u");
for (int k = 0; k < 4 - ss.length(); k++) {
sb.append('0');
}
sb.append(ss.toUpperCase());
} else {
sb.append(ch);
}
}
}
return sb.toString();
}
}
/**
* 用半角的特殊符号代替全角的特殊符号
* 防止特殊字符在传输参数时出现错误
*
*/
public class ReplaceStrE{
public static String rightToError(String ss){
String strs;
String strs1;
String strs2;
String strs3;
String strs4;
try{
strs = ss.replace('＃','#');
}
catch(Exception ex){
return ss;
}
try{
strs1 = strs.replace('＂','"');
}
catch(Exception ex){
return strs;
}
try{
strs2 = strs1.replace(' ','&');
}
catch(Exception ex){
return strs1;
}
try{
strs3 = strs2.replace('＋','+');
}
catch(Exception ex){
return strs2;
}
try{
strs4 = strs3.replace('＇','/'');
}
catch(Exception ex){
return ss;
}
return strs4;
}
}
/**
* Big5字与Unicode的互换
* 转换后的正常字型
*/
import java.io.*;
public class MyUtil{
public static String big5ToUnicode(String s){
try{
return new String(s.getBytes("ISO8859_1"), "Big5");
}
catch (UnsupportedEncodingException uee){
return s;
}
}
public static String UnicodeTobig5(String s){
try{
return new String(s.getBytes("Big5"), "ISO8859_1");
}
catch (UnsupportedEncodingException uee){
return s;
}
}
public static String toHexString(String s){
String str="";
for (int i=0; i<s.length(); i++){
int ch=(int)s.charAt(i);
String s4="0000"+Integer.toHexString(ch);
str=str+s4.substring(s4.length()-4)+" ";
}
return str;
}
}
- 超强的日期处理类：
- package com.sipgl.eam.utils;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.LinkedHashMap;
/**
* 日期公用处理类
*
* @author SongJun
* @version 1.3
*/
public class DateUtil {
/**
* 解析一个日期之间的所有月份
*
* @param beginDateStr
* @param endDateStr
* @return
*/
public static ArrayList getMonthList(String beginDateStr, String endDateStr) {
// 指定要解析的时间格式
SimpleDateFormat f = new SimpleDateFormat("yyyy-MM");
// 返回的月份列表
String sRet = "";
// 定义一些变量
Date beginDate = null;
Date endDate = null;
GregorianCalendar beginGC = null;
GregorianCalendar endGC = null;
ArrayList list = new ArrayList();
try {
// 将字符串parse成日期
beginDate = f.parse(beginDateStr);
endDate = f.parse(endDateStr);
// 设置日历
beginGC = new GregorianCalendar();
beginGC.setTime(beginDate);
endGC = new GregorianCalendar();
endGC.setTime(endDate);
// 直到两个时间相同
while (beginGC.getTime().compareTo(endGC.getTime()) <= 0) {
sRet = beginGC.get(Calendar.YEAR) + "-"
+ (beginGC.get(Calendar.MONTH) + 1);
list.add(sRet);
// 以月为单位，增加时间
beginGC.add(Calendar.MONTH, 1);
}
return list;
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
/**
* 解析一个日期段之间的所有日期
*
* @param beginDateStr
* 开始日期
* @param endDateStr
* 结束日期
* @return
*/
public static ArrayList getDayList(String beginDateStr, String endDateStr) {
// 指定要解析的时间格式
SimpleDateFormat f = new SimpleDateFormat("yyyy-MM-dd");
// 定义一些变量
Date beginDate = null;
Date endDate = null;
Calendar beginGC = null;
Calendar endGC = null;
ArrayList list = new ArrayList();
try {
// 将字符串parse成日期
beginDate = f.parse(beginDateStr);
endDate = f.parse(endDateStr);
// 设置日历
beginGC = Calendar.getInstance();
beginGC.setTime(beginDate);
endGC = Calendar.getInstance();
endGC.setTime(endDate);
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
// 直到两个时间相同
while (beginGC.getTime().compareTo(endGC.getTime()) <= 0) {
list.add(sdf.format(beginGC.getTime()));
// 以日为单位，增加时间
beginGC.add(Calendar.DAY_OF_MONTH, 1);
}
return list;
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
public static ArrayList getYearList() {
ArrayList list = new ArrayList();
Calendar c = null;
c = Calendar.getInstance();
c.setTime(new Date());
int currYear = Calendar.getInstance().get(Calendar.YEAR);
int startYear = currYear - 5;
int endYear = currYear + 10;
for (int i = startYear; i < endYear; i++) {
list.add(new Integer(i));
}
return list;
}
public static int getCurrYear() {
return Calendar.getInstance().get(Calendar.YEAR);
}
/**
* 得到某一年周的总数
*
* @param year
* @return
*/
public static LinkedHashMap getWeekList(int year) {
LinkedHashMap map = new LinkedHashMap();
Calendar c = new GregorianCalendar();
c.set(year, Calendar.DECEMBER, 31, 23, 59, 59);
int count = getWeekOfYear(c.getTime());
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
String dayOfWeekStart = "";
String dayOfWeekEnd = "";
for (int i = 1; i <= count; i++) {
dayOfWeekStart = sdf.format(getFirstDayOfWeek(year, i));
dayOfWeekEnd = sdf.format(getLastDayOfWeek(year, i));
map.put(new Integer(i), "第"+i+"周(从"+dayOfWeekStart + "至" + dayOfWeekEnd+")");
}
return map;
}
/**
* 得到一年的总周数
* @param year
* @return
*/
public static int getWeekCountInYear(int year){
Calendar c = new GregorianCalendar();
c.set(year, Calendar.DECEMBER, 31, 23, 59, 59);
int count = getWeekOfYear(c.getTime());
return count;
}
/**
* 取得当前日期是多少周
*
* @param date
* @return
*/
public static int getWeekOfYear(Date date) {
Calendar c = new GregorianCalendar();
c.setFirstDayOfWeek(Calendar.MONDAY);
c.setMinimalDaysInFirstWeek(7);
c.setTime(date);
return c.get(Calendar.WEEK_OF_YEAR);
}
/**
* 得到某年某周的第一天
*
* @param year
* @param week
* @return
*/
public static Date getFirstDayOfWeek(int year, int week) {
Calendar c = new GregorianCalendar();
c.set(Calendar.YEAR, year);
c.set(Calendar.MONTH, Calendar.JANUARY);
c.set(Calendar.DATE, 1);
Calendar cal = (GregorianCalendar) c.clone();
cal.add(Calendar.DATE, week * 7);
return getFirstDayOfWeek(cal.getTime());
}
/**
* 得到某年某周的最后一天
*
* @param year
* @param week
* @return
*/
public static Date getLastDayOfWeek(int year, int week) {
Calendar c = new GregorianCalendar();
c.set(Calendar.YEAR, year);
c.set(Calendar.MONTH, Calendar.JANUARY);
c.set(Calendar.DATE, 1);
Calendar cal = (GregorianCalendar) c.clone();
cal.add(Calendar.DATE, week * 7);
return getLastDayOfWeek(cal.getTime());
}
/**
* 得到某年某月的第一天
* @param year
* @param month
* @return
*/
public static Date getFirestDayOfMonth(int year,int month){
month = month-1;
Calendar c = Calendar.getInstance();
c.set(Calendar.YEAR, year);
c.set(Calendar.MONTH, month);
int day = c.getActualMinimum(c.DAY_OF_MONTH);
c.set(Calendar.DAY_OF_MONTH, day);
return c.getTime();
}
/**
* 提到某年某月的最后一天
* @param year
* @param month
* @return
*/
public static Date getLastDayOfMonth(int year,int month){
month = month-1;
Calendar c = Calendar.getInstance();
c.set(Calendar.YEAR, year);
c.set(Calendar.MONTH, month);
int day = c.getActualMaximum(c.DAY_OF_MONTH);
c.set(Calendar.DAY_OF_MONTH, day);
return c.getTime();
}
/**
* 取得当前日期所在周的第一天
*
* @param date
* @return
*/
public static Date getFirstDayOfWeek(Date date) {
Calendar c = new GregorianCalendar();
c.setFirstDayOfWeek(Calendar.MONDAY);
c.setTime(date);
c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek()); // Monday
return c.getTime();
}
/**
* 取得当前日期所在周的最后一天
*
* @param date
* @return
*/
public static Date getLastDayOfWeek(Date date) {
Calendar c = new GregorianCalendar();
c.setFirstDayOfWeek(Calendar.MONDAY);
c.setTime(date);
c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek() + 6); // Sunday
return c.getTime();
}
}
- 一个超强的字符串处理类
- package net.java2000.tools;
/**
* Title: Java Bean 工具
* Description:
* Copyright: Copyright (c) 2001
* Company: JAVA世纪网 http://www.java2000.net
* @author 赵学庆
* @version 1.0
*/
import java.util.*;
import java.util.regex.Pattern;
public class StrTools {
/**
* 分割字符串
*
* @param str String 原始字符串
* @param splitsign String 分隔符
* @return String[] 分割后的字符串数组
*/
@SuppressWarnings("unchecked")
public static String[] split(String str, String splitsign) {
int index;
if (str == null || splitsign == null)
return null;
ArrayList al = new ArrayList();
while ((index = str.indexOf(splitsign)) != -1) {
al.add(str.substring(0, index));
str = str.substring(index + splitsign.length());
}
al.add(str);
return (String[]) al.toArray(new String[0]);
}
/**
* 替换字符串
*
* @param from String 原始字符串
* @param to String 目标字符串
* @param source String 母字符串
* @return String 替换后的字符串
*/
public static String replace(String from, String to, String source) {
if (source == null || from == null || to == null)
return null;
StringBuffer bf = new StringBuffer("");
int index = -1;
while ((index = source.indexOf(from)) != -1) {
bf.append(source.substring(0, index) + to);
source = source.substring(index + from.length());
index = source.indexOf(from);
}
bf.append(source);
return bf.toString();
}
/**
* 替换字符串，能能够在HTML页面上直接显示(替换双引号和小于号)
*
* @param str String 原始字符串
* @return String 替换后的字符串
*/
public static String htmlencode(String str) {
if (str == null) {
return null;
}
return replace("/"", """, replace("<", "<", str));
}
/**
* 替换字符串，将被编码的转换成原始码（替换成双引号和小于号）
*
* @param str String
* @return String
*/
public static String htmldecode(String str) {
if (str == null) {
return null;
}
return replace(""", "/"", replace("<", "<", str));
}
private static final String _BR = "<br/>";
/**
* 在页面上直接显示文本内容，替换小于号，空格，回车，TAB
*
* @param str String 原始字符串
* @return String 替换后的字符串
*/
public static String htmlshow(String str) {
if (str == null) {
return null;
}
str = replace("<", "<", str);
str = replace(" ", " ", str);
str = replace("/r/n", _BR, str);
str = replace("/n", _BR, str);
str = replace("/t", " ", str);
return str;
}
/**
* 返回指定字节长度的字符串
*
* @param str String 字符串
* @param length int 指定长度
* @return String 返回的字符串
*/
public static String toLength(String str, int length) {
if (str == null) {
return null;
}
if (length <= 0) {
return "";
}
try {
if (str.getBytes("GBK").length <= length) {
return str;
}
} catch (Exception ex) {
}
StringBuffer buff = new StringBuffer();
int index = 0;
char c;
length -= 3;
while (length > 0) {
c = str.charAt(index);
if (c < 128) {
length--;
} else {
length--;
length--;
}
buff.append(c);
index++;
}
buff.append("...");
return buff.toString();
}
/**
* 判断是否为整数
*
* @param str 传入的字符串
* @return 是整数返回true,否则返回false
*/
public static boolean isInteger(String str) {
Pattern pattern = Pattern.compile("^[-//+]?[//d]*$");
return pattern.matcher(str).matches();
}
/**
* 判断是否为浮点数，包括double和float
*
* @param str 传入的字符串
* @return 是浮点数返回true,否则返回false
*/
public static boolean isDouble(String str) {
Pattern pattern = Pattern.compile("^[-//+]?[.//d]*$");
return pattern.matcher(str).matches();
}
/**
* 判断输入的字符串是否符合Email样式.
*
* @param str 传入的字符串
* @return 是Email样式返回true,否则返回false
*/
public static boolean isEmail(String str) {
Pattern pattern = Pattern.compile("^//w+([-+.]//w+)*@//w+([-.]//w+)*//.//w+([-.]//w+)*$");
return pattern.matcher(str).matches();
}
/**
* 判断输入的字符串是否为纯汉字
*
* @param str 传入的字符窜
* @return 如果是纯汉字返回true,否则返回false
*/
public static boolean isChinese(String str) {
Pattern pattern = Pattern.compile("[/u0391-/uFFE5]+$");
return pattern.matcher(str).matches();
}
/**
* 是否为空白,包括null和""
*
* @param str
* @return
*/
public static boolean isBlank(String str) {
return str == null || str.trim().length() == 0;
}
/**
* 判断是否为质数
*
* @param x
* @return
*/
public static boolean isPrime(int x) {
if (x <= 7) {
if (x == 2 || x == 3 || x == 5 || x == 7)
return true;
}
int c = 7;
if (x % 2 == 0)
return false;
if (x % 3 == 0)
return false;
if (x % 5 == 0)
return false;
int end = (int) Math.sqrt(x);
while (c <= end) {
if (x % c == 0) {
return false;
}
c += 4;
if (x % c == 0) {
return false;
}
c += 2;
if (x % c == 0) {
return false;
}
c += 4;
if (x % c == 0) {
return false;
}
c += 2;
if (x % c == 0) {
return false;
}
c += 4;
if (x % c == 0) {
return false;
}
c += 6;
if (x % c == 0) {
return false;
}
c += 2;
if (x % c == 0) {
return false;
}
c += 6;
}
return true;
}
public static void main(String[] args) {
String[] numbers = { "12345", "-12345", "123.45", "-123.45", ".12345", "-.12345", "a12345", "12345a", "123.a45" };
for (String str : numbers) {
System.out.println(str + "=" + isInteger(str) + " " + isDouble(str));
}
String[] emails = { "1@2.com", "1.2@3.com", "1@3.4.5.com" };
for (String str : emails) {
System.out.println(str + "=" + isEmail(str));
}
String[] chineses = { "中国", "1中国", "中国1", "1中国2", "中1国" };
for (String str : chineses) {
System.out.println(str + "=" + isChinese(str));
}
}
}
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