This article describes the Java project thinking and practical strategies to deal with the amount;
When do electricity suppliers or projects with transactional requirements, must be related to the amount of model information, such as account balances, frozen balance, available balance, you can withdraw cash balances and so on, all money associated with the field, can be collectively referred to as the amount of information ;
The amount of information, at least to consider the design from several dimensions, the first is the type of database storage usage, and the second is how to ensure the accuracy of the calculation process, and the third is what type of adoption for page display (there is usually rounded to two decimal places, etc. demand);
For storage type, Mysql be considered Bigint storage, the unit is integer division (also use decimal, but to keep in mind, global must be unified, either all bigint, or all decimal), corresponds to the entity class java is Long types of variables, when all operations to be carried out using BigDecimal java (Remember, any arithmetic calculations must be used), such programs also use the code examples in this article, the following is a financial amount of an actual process used in the project tools, now share with you my colleagues, I hope this can inspire and help you.
import java.math.BigDecimal;
import java.text.DecimalFormat;
/**
* 金额转换工具类
* @author Administrator
*
*/
public class AmountUtil {
/**
* 返回单位元的2位小数String值
* @param longVal 单位：分
* @return
*/
public static String longToString(long longVal) {
BigDecimal bdCent = new BigDecimal(StringUtil.getString(longVal));
BigDecimal bd100 = new BigDecimal("100");
BigDecimal bdYuan = bdCent.divide(bd100);
String str = formatToNumber(bdYuan);
return str;
}
/**
* 返回单位元的2位小数String值
* @param longVal
* @return
*/
public static String double2p(double doubleVal) {
String str = formatToNumber(new BigDecimal(doubleVal));
return str;
}
/**
* 1.0~1之间的BigDecimal小数，格式化后失去前面的0,则前面直接加上0。
* 2.传入的参数等于0，则直接返回字符串"0.00"
* 3.大于1的小数，直接格式化返回字符串
* @param obj传入的小数
* @return
*/
public static String formatToNumber(BigDecimal obj) {
DecimalFormat df = new DecimalFormat("#.00");
if(obj.compareTo(BigDecimal.ZERO)==0) {
return "0.00";
}else if(obj.compareTo(BigDecimal.ZERO)>0&&obj.compareTo(new BigDecimal(1))<0){
return "0"+df.format(obj).toString();
}else {
return df.format(obj).toString();
}
}
}The code used in StringUtil categories:
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.security.MessageDigest;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* 字符串工具类，提供一些字符串相关的便捷方法
*/
public class StringUtil {
private StringUtil() {
throw new AssertionError();
}
public static Long strToLong(String str) {
try {
return Long.parseLong(str);
} catch (Exception e) {
return null;
}
}
/**
* <pre>
* isBlank(null) = true;
* isBlank("") = true;
* isBlank(" ") = true;
* isBlank("a") = false;
* isBlank("a ") = false;
* isBlank(" a") = false;
* isBlank("a b") = false;
* </pre>
*
* @param str 字符串
* @return 如果字符串为空或者长度为0，返回true，否则返回false
*/
public static boolean isBlank(String str) {
return (str == null || str.trim().length() == 0);
}
/**
* <pre>
* isEmpty(null) = true;
* isEmpty("") = true;
* isEmpty(" ") = false;
* </pre>
*
* @param c 字符序列
* @return 如果字符序列为空或者长度为0，返回true，否则返回false
*/
public static boolean isEmpty(CharSequence c) {
return (c == null || c.length() == 0);
}
/**
* 获取字符序列的长度
* <pre>
* length(null) = 0;
* length(\"\") = 0;
* length(\"abc\") = 3;
* </pre>
*
* @param c 字符序列
* @return 如果字符序列为空，返回0，否则返回字符序列的长度
*/
public static int length(CharSequence c) {
return c == null ? 0 : c.length();
}
/**
* null Object to empty string
* 空对象转化成空字符串
* <pre>
* nullStrToEmpty(null) = "";
* nullStrToEmpty("") = "";
* nullStrToEmpty("aa") = "aa";
* </pre>
*
* @param object 对象
* @return String
*/
public static String getString(Object object) {
return object == null ?
"" : (object instanceof String ? (String)object : object.toString());
}
/**
* @param str str
* @return String
*/
public static String capitalizeFirstLetter(String str) {
if (isEmpty(str)) {
return str;
}
char c = str.charAt(0);
return (!Character.isLetter(c) || Character.isUpperCase(c))
? str
: new StringBuilder(str.length()).append(
Character.toUpperCase(c))
.append(str.substring(1))
.toString();
}
/**
* 用utf-8编码
* @param str 字符串
* @return 返回一个utf8的字符串
*/
public static String utf8Encode(String str) {
if (!isEmpty(str) || str.getBytes().length != str.length()) {
try {
return URLEncoder.encode(str, "utf-8");
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(
"UnsupportedEncodingException occurred. ", e);
}
}
return str;
}
/**
* @param href 字符串
* @return 返回一个html
*/
public static String getHrefInnerHtml(String href) {
if (isEmpty(href)) {
return "";
}
String hrefReg = ".*<[\\s]*a[\\s]*.*>(.+?)<[\\s]*/a[\\s]*>.*";
Pattern hrefPattern = Pattern.compile(hrefReg, Pattern.CASE_INSENSITIVE);
Matcher hrefMatcher = hrefPattern.matcher(href);
if (hrefMatcher.matches()) {
return hrefMatcher.group(1);
}
return href;
}
/**
* @param s 字符串
* @return String
*/
public static String fullWidthToHalfWidth(String s) {
if (isEmpty(s)) {
return s;
}
char[] source = s.toCharArray();
for (int i = 0; i < source.length; i++) {
if (source[i] == 12288) {
source[i] = ' ';
// } else if (source[i] == 12290) {
// source[i] = '.';
}
else if (source[i] >= 65281 && source[i] <= 65374) {
source[i] = (char) (source[i] - 65248);
}
else {
source[i] = source[i];
}
}
return new String(source);
}
/**
* @param s 字符串
* @return 返回的数值
*/
public static String halfWidthToFullWidth(String s) {
if (isEmpty(s)) {
return s;
}
char[] source = s.toCharArray();
for (int i = 0; i < source.length; i++) {
if (source[i] == ' ') {
source[i] = (char) 12288;
// } else if (source[i] == '.') {
// source[i] = (char)12290;
}
else if (source[i] >= 33 && source[i] <= 126) {
source[i] = (char) (source[i] + 65248);
}
else {
source[i] = source[i];
}
}
return new String(source);
}
/**
* @param str 资源
* @return 特殊字符串切换
*/
public static String replaceBlanktihuan(String str) {
String dest = "";
if (str != null) {
Pattern p = Pattern.compile("\\s*|\t|\r|\n");
Matcher m = p.matcher(str);
dest = m.replaceAll("");
}
return dest;
}
/**
* 判断给定的字符串是否为null或者是空的
* @param string 给定的字符串
*/
public static boolean isEmpty(String string) {
return string == null || "".equals(string.trim());
}
/**
* 判断给定的字符串是否不为null且不为空
* @param string 给定的字符串
*/
public static boolean isNotEmpty(String string) {
return !isEmpty(string);
}
/**
* 判断给定的字符串数组中的所有字符串是否都为null或者是空的
* @param strings 给定的字符串
*/
public static boolean isEmpty(String... strings) {
boolean result = true;
for (String string : strings) {
if (isNotEmpty(string)) {
result = false;
break;
}
}
return result;
}
/**
* 判断给定的字符串数组中是否全部都不为null且不为空
*
* @param strings 给定的字符串数组
* @return 是否全部都不为null且不为空
*/
public static boolean isNotEmpty(String... strings) {
boolean result = true;
for (String string : strings) {
if (isEmpty(string)) {
result = false;
break;
}
}
return result;
}
/**
* 如果字符串是null或者空就返回""
*/
public static String filterEmpty(String string) {
return StringUtil.isNotEmpty(string) ? string : "";
}
/**
* 在给定的字符串中，用新的字符替换所有旧的字符
* @param string 给定的字符串
* @param oldchar 旧的字符
* @param newchar 新的字符
* @return 替换后的字符串
*/
public static String replace(String string, char oldchar, char newchar) {
char chars[] = string.toCharArray();
for (int w = 0; w < chars.length; w++) {
if (chars[w] == oldchar) {
chars[w] = newchar;
break;
}
}
return new String(chars);
}
/**
* 把给定的字符串用给定的字符分割
* @param string 给定的字符串
* @param ch 给定的字符
* @return 分割后的字符串数组
*/
public static String[] split(String string, char ch) {
ArrayList<String> stringList = new ArrayList<String>();
char chars[] = string.toCharArray();
int nextStart = 0;
for (int w = 0; w < chars.length; w++) {
if (ch == chars[w]) {
stringList.add(new String(chars, nextStart, w - nextStart));
nextStart = w + 1;
if (nextStart ==
chars.length) { //当最后一位是分割符的话，就再添加一个空的字符串到分割数组中去
stringList.add("");
}
}
}
if (nextStart <
chars.length) { //如果最后一位不是分隔符的话，就将最后一个分割符到最后一个字符中间的左右字符串作为一个字符串添加到分割数组中去
stringList.add(new String(chars, nextStart,
chars.length - 1 - nextStart + 1));
}
return stringList.toArray(new String[stringList.size()]);
}
/**
* 计算给定的字符串的长度，计算规则是：一个汉字的长度为2，一个字符的长度为1
*
* @param string 给定的字符串
* @return 长度
*/
public static int countLength(String string) {
int length = 0;
char[] chars = string.toCharArray();
for (int w = 0; w < string.length(); w++) {
char ch = chars[w];
if (ch >= '\u0391' && ch <= '\uFFE5') {
length++;
length++;
}
else {
length++;
}
}
return length;
}
@SuppressWarnings("unused")
private static char[] getChars(char[] chars, int startIndex) {
int endIndex = startIndex + 1;
//如果第一个是数字
if (Character.isDigit(chars[startIndex])) {
//如果下一个是数字
while (endIndex < chars.length &&
Character.isDigit(chars[endIndex])) {
endIndex++;
}
}
char[] resultChars = new char[endIndex - startIndex];
System.arraycopy(chars, startIndex, resultChars, 0, resultChars.length);
return resultChars;
}
/**
* 是否全是数字
*/
public static boolean isAllDigital(char[] chars) {
boolean result = true;
for (int w = 0; w < chars.length; w++) {
if (!Character.isDigit(chars[w])) {
result = false;
break;
}
}
return result;
}
/**
* 删除给定字符串中所有的旧的字符
*
* @param string 源字符串
* @param ch 要删除的字符
* @return 删除后的字符串
*/
public static String removeChar(String string, char ch) {
StringBuffer sb = new StringBuffer();
for (char cha : string.toCharArray()) {
if (cha != '-') {
sb.append(cha);
}
}
return sb.toString();
}
/**
* 删除给定字符串中给定位置处的字符
*
* @param string 给定字符串
* @param index 给定位置
*/
public static String removeChar(String string, int index) {
String result = null;
char[] chars = string.toCharArray();
if (index == 0) {
result = new String(chars, 1, chars.length - 1);
}
else if (index == chars.length - 1) {
result = new String(chars, 0, chars.length - 1);
}
else {
result = new String(chars, 0, index) +
new String(chars, index + 1, chars.length - index);
;
}
return result;
}
/**
* 删除给定字符串中给定位置处的字符
*
* @param string 给定字符串
* @param index 给定位置
* @param ch 如果同给定位置处的字符相同，则将给定位置处的字符删除
*/
public static String removeChar(String string, int index, char ch) {
String result = null;
char[] chars = string.toCharArray();
if (chars.length > 0 && chars[index] == ch) {
if (index == 0) {
result = new String(chars, 1, chars.length - 1);
}
else if (index == chars.length - 1) {
result = new String(chars, 0, chars.length - 1);
}
else {
result = new String(chars, 0, index) +
new String(chars, index + 1, chars.length - index);
;
}
}
else {
result = string;
}
return result;
}
/**
* 对给定的字符串进行空白过滤
*
* @param string 给定的字符串
* @return 如果给定的字符串是一个空白字符串，那么返回null；否则返回本身。
*/
public static String filterBlank(String string) {
if ("".equals(string)) {
return null;
}
else {
return string;
}
}
/**
* 将给定字符串中给定的区域的字符转换成小写
*
* @param str 给定字符串中
* @param beginIndex 开始索引（包括）
* @param endIndex 结束索引（不包括）
* @return 新的字符串
*/
public static String toLowerCase(String str, int beginIndex, int endIndex) {
return str.replaceFirst(str.substring(beginIndex, endIndex),
str.substring(beginIndex, endIndex)
.toLowerCase(Locale.getDefault()));
}
/**
* 将给定字符串中给定的区域的字符转换成大写
*
* @param str 给定字符串中
* @param beginIndex 开始索引（包括）
* @param endIndex 结束索引（不包括）
* @return 新的字符串
*/
public static String toUpperCase(String str, int beginIndex, int endIndex) {
return str.replaceFirst(str.substring(beginIndex, endIndex),
str.substring(beginIndex, endIndex)
.toUpperCase(Locale.getDefault()));
}
/**
* 将给定字符串的首字母转为小写
*
* @param str 给定字符串
* @return 新的字符串
*/
public static String firstLetterToLowerCase(String str) {
return toLowerCase(str, 0, 1);
}
/**
* 将给定字符串的首字母转为大写
*
* @param str 给定字符串
* @return 新的字符串
*/
public static String firstLetterToUpperCase(String str) {
return toUpperCase(str, 0, 1);
}
/**
* 将给定的字符串MD5加密
*
* @param string 给定的字符串
* @return MD5加密后生成的字符串
*/
public static String MD5(String string) {
String result = null;
try {
char[] charArray = string.toCharArray();
byte[] byteArray = new byte[charArray.length];
for (int i = 0; i < charArray.length; i++) {
byteArray[i] = (byte) charArray[i];
}
StringBuffer hexValue = new StringBuffer();
byte[] md5Bytes = MessageDigest.getInstance("MD5")
.digest(byteArray);
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));
}
result = hexValue.toString();
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
/**
* 判断给定的字符串是否以一个特定的字符串开头，忽略大小写
*
* @param sourceString 给定的字符串
* @param newString 一个特定的字符串
*/
public static boolean startsWithIgnoreCase(String sourceString, String newString) {
int newLength = newString.length();
int sourceLength = sourceString.length();
if (newLength == sourceLength) {
return newString.equalsIgnoreCase(sourceString);
}
else if (newLength < sourceLength) {
char[] newChars = new char[newLength];
sourceString.getChars(0, newLength, newChars, 0);
return newString.equalsIgnoreCase(String.valueOf(newChars));
}
else {
return false;
}
}
/**
* 判断给定的字符串是否以一个特定的字符串结尾，忽略大小写
*
* @param sourceString 给定的字符串
* @param newString 一个特定的字符串
*/
public static boolean endsWithIgnoreCase(String sourceString, String newString) {
int newLength = newString.length();
int sourceLength = sourceString.length();
if (newLength == sourceLength) {
return newString.equalsIgnoreCase(sourceString);
}
else if (newLength < sourceLength) {
char[] newChars = new char[newLength];
sourceString.getChars(sourceLength - newLength, sourceLength,
newChars, 0);
return newString.equalsIgnoreCase(String.valueOf(newChars));
}
else {
return false;
}
}
/**
* 检查字符串长度，如果字符串的长度超过maxLength，就截取前maxLength个字符串并在末尾拼上appendString
*/
public static String checkLength(String string, int maxLength, String appendString) {
if (string.length() > maxLength) {
string = string.substring(0, maxLength);
if (appendString != null) {
string += appendString;
}
}
return string;
}
/**
* 检查字符串长度，如果字符串的长度超过maxLength，就截取前maxLength个字符串并在末尾拼上…
*/
public static String checkLength(String string, int maxLength) {
return checkLength(string, maxLength, "…");
}
/**
*
* String转map
* @param str
* @return
*/
public static Map<String,Object> getStringToMap(String str){
//根据逗号截取字符串数组
String[] str1 = str.split(",");
//创建Map对象
Map<String,Object> map = new HashMap<>();
//循环加入map集合
for (int i = 0; i < str1.length; i++) {
//根据":"截取字符串数组
String[] str2 = str1[i].split(":");
//str2[0]为KEY,str2[1]为值
map.put(str2[0],str2[1]);
}
return map;
}
/**
*
* Map转String
* @param map
* @return
*/
public static String getMapToString(Map<String,Object> map){
Set<String> keySet = map.keySet();
//将set集合转换为数组
String[] keyArray = keySet.toArray(new String[keySet.size()]);
//给数组排序(升序)
Arrays.sort(keyArray);
//因为String拼接效率会很低的，所以转用StringBuilder
StringBuilder sb = new StringBuilder();
for (int i = 0; i < keyArray.length; i++) {
// 参数值为空，则不参与签名 这个方法trim()是去空格
if ((String.valueOf(map.get(keyArray[i]))).trim().length() > 0) {
sb.append(keyArray[i]).append(":").append(String.valueOf(map.get(keyArray[i])).trim());
}
if(i != keyArray.length-1){
sb.append(",");
}
}
return sb.toString();
}
}
