如果按位索引的位为1，则为true。

/*******************************************************************************

 *   Copyright 2014 Analog Devices, Inc.

 *

 *   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.nowjava;


public class Main {/* 来自 时 代 J a v a 公 众 号*/

    public static void main(String[] argv) throws Exception {

        int bits = 2;

        int index = 2;

        System.out.println(isBitSet(bits, index));

    }


    /**

     * True if bit at {@code index} in {@code bits} is one.

     * 

     * @param bits

     * @param index must be in the range [0,31] identifies which bit to clear.

     */

    public static boolean isBitSet(int bits, int index) {

        return (bits & (1 << index)) != 0;

    }