java decimal to percentage

最新推荐文章于 2024-04-19 22:14:49 发布

NukeYu

最新推荐文章于 2024-04-19 22:14:49 发布

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本文链接：https://blog.csdn.net/bugnuke123/article/details/8768605

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本文介绍了一个简单的Java程序，用于将双精度类型的数值转换为百分比，并实现数据汇总与百分比计算功能。通过实例展示了如何使用DecimalFormat类进行格式化输出，以及如何在实际业务场景中应用。

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就是简单实用了，才工作中应用到了，怕忘记就发出来。

主要功能很简单，但是处理起来就是很繁琐，说明以下，当拿到一个拿到一个小数点（double）类型，然后进行转换百分比。

package com.ubs.ifop.service.statistics.webapp.action;

import java.math.BigDecimal;
import java.text.DecimalFormat;
import java.util.ArrayList;

import com.ubs.ifop.service.statistics.webapp.items.PieChartItem;

public class test {

static String FORMAT_PERCENT_DEFAULT = "###,##0.00%";
private static DecimalFormat decFormatter = new DecimalFormat();

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub

ArrayList pieChartSolist = new ArrayList();
double amount = 0.0D;

String result = toPercentage("0.122222");
System.out.println(result);

  // test
  /*
   * for (int i = 1; i < list.size(); i++) {
   *
   * String key =((String[]) list.get(i))[0]; String value = ((String[])
   * list.get(i))[1]; PieChartItem so = new PieChartItem();
   * so.setName(key); so.setValue(value); pieChartSolist.add(so); amount =
   * amount + Double.parseDouble(value); }
   */

// 16_AMEX-LUX,82_,520_EFUND-LUX,1721_EPEX-LUX,920_EPF-LUX,11_TRADER-LUX,3059_estmt

  PieChartItem so1 = new PieChartItem();
  so1.setName("AMEX-LUX");
  so1.setValue("16");

  PieChartItem so2 = new PieChartItem();
  so2.setName("CHDRPT-LUX");
  so2.setValue("82");

/*  PieChartItem so3 = new PieChartItem();
  so3.setName("EPEX-LUX");
  so3.setValue("1721");
  PieChartItem so4 = new PieChartItem();
  so4.setName("EPF-LUX");
  so4.setValue("920");
  PieChartItem so5 = new PieChartItem();
  so5.setName("TRADER-LUX");
  so5.setValue("11");
  PieChartItem so6 = new PieChartItem();
  so6.setName("estmt");
  so6.setValue("3059");*/
  pieChartSolist.add(so1);
  pieChartSolist.add(so2);
/*  pieChartSolist.add(so3);
  pieChartSolist.add(so4);
  pieChartSolist.add(so5);
  pieChartSolist.add(so6);*/

for (int i = 0; i < pieChartSolist.size(); i++) {

   PieChartItem so = (PieChartItem) pieChartSolist.get(i);
   amount = amount + Double.parseDouble(so.getValue());
  }
  System.out.println(amount);
  for (int i = 0; i < pieChartSolist.size(); i++) {
   PieChartItem item = (PieChartItem) pieChartSolist.get(i);
   double aa = Double.parseDouble(item.getValue());

   double bb = aa / amount;
   //System.out.println("bb :" + bb);
   item.setTotalAmount(amount);


   System.out.println(item.getValue() + "   "+test.toPercentage(String.valueOf(bb)));
  }

}

public static String toPercentage(String value1) {

// disabled multiplier
return formatNumeric(value1, FORMAT_PERCENT_DEFAULT, 100);
}

protected static int getDecimalPlace(String format) {

  int decimalPlace = 0;
  int dseparator = format.lastIndexOf(".");
  if (dseparator == -1) {
   // if no decimal place found, set as zero
   dseparator = format.length();
  } else {
   // add 1 to move the character after decimal separator
   dseparator += 1;
  }
  decimalPlace = format.length() - dseparator;

  // check the % character
  int percentIndex = format.indexOf("%");
  if (percentIndex != -1) {
   // if the format contained "%", the value will be multiplied by 100
   // before display it
   // then if % character found, add two digits for rounding
   if (dseparator <= percentIndex) {
    // if "%" found after the decimal separator, just add one
    // character
    decimalPlace += 1;
   } else {
    decimalPlace += 2;
   }
  }
  return decimalPlace;
}

public static String formatNumeric(String value1, String format,
int multiplier) {

BigDecimal value = new BigDecimal(value1.toString());
int decimalPlace = getDecimalPlace(format);

decFormatter.applyPattern(format);

  if (multiplier != 0) {
   decFormatter.setMultiplier(multiplier);
  }

return format(value, decimalPlace, decFormatter);
}

protected static String format(BigDecimal value, int decimalPlace,
DecimalFormat decFormat) {

  BigDecimal diff = new BigDecimal("0");
  BigDecimal tempValue = new BigDecimal(String.valueOf(value));
  tempValue = tempValue.setScale(decimalPlace, BigDecimal.ROUND_HALF_UP);
  return decFormat.format(tempValue.add(diff));
}

}