字符串 千分位分割 和 保留制定小数位

import org.junit.Test;

import java.math.BigDecimal;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.text.ParseException;

public class Demo1 {
    public static void main(String[] args) {
        BigDecimal bd = new BigDecimal(123456789.345678+"%");
        System.out.println(parseNumber(",###.###", bd)); // out: 123,456,789.30
    }

    @Test
    public void test1(){
//        System.out.println(chuliStr("123234565.1235", 3, ",###"));
//        System.out.println(chuliStr("123234565.12", 3, ",###"));
//        System.out.println(chuliStr("123234565.99999", 4, ",###"));
        System.out.println(chuliStr("125.12336%", 4, ",###"));
//        System.out.println(chuliStr("", 4, ",###"));
//        System.out.println(chuliStr("汉字", 4, ",###"));
//        System.out.println(chuliStr(".", 4, ",###"));

    }

    /**
     * 处理字符串保留指定小数位
     * @param str
     * @param number
     * @return
     */
    public static String chuliStr(String str,Integer number,String pattern){
        try {
            if (checkBigDecimal(str)){
                //如果是浮点型，需要保留指定的格式通常是千分位
                BigDecimal bd = new BigDecimal(str);
                if (number!=null&&number!=0){
                    String tag = ".";
                    for (Integer i = 0; i < number; i++) {
                        tag = tag+"#";
                    }
                    pattern = pattern + tag;
                }
                DecimalFormat df = new DecimalFormat(pattern);
                return df.format(bd);
            }else if (str.contains("%")){
                //如果是百分比，需要保留小数位
                return chuliParcent(str,number);
            }else {
                return str;
            }
        }catch (Exception e){
            return str;
        }
    }

    public static boolean checkBigDecimal(String targetString) {
        BigDecimal tmp = null;
        try {
            tmp = new BigDecimal(targetString);
        } catch (NumberFormatException e) {
        }
        if (tmp!=null) {
            return true;
        }
        return false;
    }


    /**
     *
     * @param val
     * @param number 多少个小数位
     * @return
     */
    public static String chuliParcent(String val,Integer number){
        try {
            if (!"".equals(val)&&null!=val&&val.endsWith("%")){
                //移除最后一个字符
                String substring = val.substring(0, val.length() - 1);
                //判断是否是一个数字
                if (checkBigDecimal(substring)){
                    //如果是转化为小数
                    val = NumberFormat.getPercentInstance().parse(val).toString();
                    //保留指定位数
                    NumberFormat percentInstance = NumberFormat.getPercentInstance();
                    percentInstance.setMaximumFractionDigits(number); // 保留小数两位
                    return percentInstance.format(Double.parseDouble(val));
                }
            }
        }catch (Exception e){
            e.printStackTrace();
        }
        return val;
    }

    @Test
    public void test22(){
        try {
//            Number val = NumberFormat.getPercentInstance().parse("67.89%");
//            System.out.println(val.toString());
            NumberFormat percentInstance = NumberFormat.getPercentInstance();
            percentInstance.setMaximumFractionDigits(2); // 保留小数两位
            String format = percentInstance.format(Double.parseDouble("112233.234576543456")); // 结果是81.25% ，最后一们四舍五入了
            System.out.println(format);
        } catch (Exception e) {
            e.printStackTrace();
        }


    }

    /**
     * 保留指定的位数
     * @param pattern
     * @param bd
     * @return
     */
    public static String parseNumber(String pattern, BigDecimal bd) {
        DecimalFormat df = new DecimalFormat(pattern);
        return df.format(bd);
    }
}