將BigDecimal轉(zhuǎn)成字符串為科學(xué)計數(shù)法的踩坑記錄
BigDecimal轉(zhuǎn)字符串為科學(xué)計數(shù)法踩坑
場景
在開發(fā)工程中,在金額方面都會定義bigdecimal類型,當(dāng)然有時候也需要將金額轉(zhuǎn)成字符串。我們可能會很自然的寫成 金額.toString()方法如:
costBudgetEntity.getInitTotalAmount().toString()//獲取初始預(yù)算金額的字符串
當(dāng)然當(dāng)金額過小時,轉(zhuǎn)成字符串,是沒有任何問題的,但當(dāng)金額數(shù)值較大時,轉(zhuǎn)成的字符串時科學(xué)計數(shù)法格式,這往往不是我們想要的格式。

因此
costBudgetEntity.getInitTotalAmount().toString()//金額為12000000輸出的結(jié)果為1.2E+7這種的字符串
然后根據(jù)這種字符串,無法做一些想要的業(yè)務(wù)處理
解決
查看BigDecimal的API后,得知有個toPlainString()方法, 此方法的返回類型為String ,它返回此BigDecimal對象的字符串表示形式,不需要任何指數(shù)。
/**
* Returns a string representation of this {@code BigDecimal}
* without an exponent field. For values with a positive scale,
* the number of digits to the right of the decimal point is used
* to indicate scale. For values with a zero or negative scale,
* the resulting string is generated as if the value were
* converted to a numerically equal value with zero scale and as
* if all the trailing zeros of the zero scale value were present
* in the result.
*
* The entire string is prefixed by a minus sign character '-'
* (<tt>'\u002D'</tt>) if the unscaled value is less than
* zero. No sign character is prefixed if the unscaled value is
* zero or positive.
*
* Note that if the result of this method is passed to the
* {@linkplain #BigDecimal(String) string constructor}, only the
* numerical value of this {@code BigDecimal} will necessarily be
* recovered; the representation of the new {@code BigDecimal}
* may have a different scale. In particular, if this
* {@code BigDecimal} has a negative scale, the string resulting
* from this method will have a scale of zero when processed by
* the string constructor.
*
* (This method behaves analogously to the {@code toString}
* method in 1.4 and earlier releases.)
*
* @return a string representation of this {@code BigDecimal}
* without an exponent field.
* @since 1.5
* @see #toString()
* @see #toEngineeringString()
*/
public String toPlainString() {
if(scale==0) {
if(intCompact!=INFLATED) {
return Long.toString(intCompact);
} else {
return intVal.toString();
}
}
if(this.scale<0) { // No decimal point
if(signum()==0) {
return "0";
}
int tailingZeros = checkScaleNonZero((-(long)scale));
StringBuilder buf;
if(intCompact!=INFLATED) {
buf = new StringBuilder(20+tailingZeros);
buf.append(intCompact);
} else {
String str = intVal.toString();
buf = new StringBuilder(str.length()+tailingZeros);
buf.append(str);
}
for (int i = 0; i < tailingZeros; i++)
buf.append('0');
return buf.toString();
}
String str ;
if(intCompact!=INFLATED) {
str = Long.toString(Math.abs(intCompact));
} else {
str = intVal.abs().toString();
}
return getValueString(signum(), str, scale);
}此時,我們在debug查看:

costBudgetEntity.getInitTotalAmount().toPlainString() //金額為12000000輸出的結(jié)果為12000000字符串
案例演示

BigDecimal變科學(xué)計數(shù)法
阿里OTS存儲BigDecimal
當(dāng)BigDecimal數(shù)據(jù)大于9,999,999時
后就變成科學(xué)計數(shù)法了。
如10,000,000 就變?yōu)?.0E7
接收端應(yīng)該注意
也需要用BigDecimal,要是使用Integer接收,就可能出現(xiàn)異常
以上為個人經(jīng)驗,希望能給大家一個參考,也希望大家多多支持腳本之家。
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