Parses a string to produce a Double with a number of fraction digits. - Java java.lang

Java examples for java.lang:double

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Description

Parses a string to produce a Double with a number of fraction digits.

Demo Code

/**//from   w  w  w  .jav a 2  s  .  com
 * Copyright (C) 2012 Red Hat, Inc. and/or its affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
//package com.java2s;
import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;

import java.util.Locale;

public class Main {
    /**
     * Parses a string to produce a Double with a number of fraction
     * digits.
     *
     * @param text     string to parse
     * @param decimals number of fraction digits
     * @return Double parsed from string. In case of error, returns null.
     */
    public static Double strToDouble(String text, int decimals) {
        try {
            return new Double(getFormat(decimals).parse(text).doubleValue());
        } catch (Exception except) {
            except.printStackTrace();
            return null;
        }
    }

    /**
     * Returns the decimal formatter, which has a number of decimals.
     *
     * @param decimals number of decimals
     * @return desired DecimalFormat
     */
    private static DecimalFormat getFormat(int decimals) {
        DecimalFormat df;
        df = (DecimalFormat) DecimalFormat.getInstance(Locale.getDefault());
        DecimalFormatSymbols dsym = df.getDecimalFormatSymbols();
        char decimalSeparator = dsym.getDecimalSeparator();

        StringBuffer pattern = new StringBuffer("0");
        pattern.append(decimalSeparator);
        for (int i = 0; i < decimals; i++)
            pattern.append("0");

        DecimalFormat numberFormat = new DecimalFormat(pattern.toString());
        DecimalFormatSymbols decimalSymb;
        decimalSymb = numberFormat.getDecimalFormatSymbols();

        numberFormat.setGroupingSize(50);
        decimalSymb.setDecimalSeparator(decimalSeparator);
        numberFormat.setDecimalFormatSymbols(decimalSymb);

        return numberFormat;
    }
}

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