背景

  • Java基础-Java位运算 在JAVA基础篇中我们梳理了基础知识，学了理论后我们要用于实际项目中，我们知道二进制位是各种00010110101，组成，不是0就是1

  • 上面这种情况在项目中是不是可以存放各种状态位，1就是代表开启，0就是代表未开启，上面有多少位就可以代表多少个状态，而且在数据库里面只要存放一个int字段就行，后续获取和设置都可以使用位运算来处理

代码实现

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package com.songsy.springboot.test.service.util;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * 二进制复合状态工具类
 * @author songshuiyang
 * @date 2023/5/2 12:57
 */
public class BinaryStateUtils {

    private static final Logger LOGGER = LoggerFactory.getLogger(BinaryStateUtils.class);

    /**
     * 复合状态位
     */
    public enum StateEnum{
        ORDER(0,"已下单"),
        PUSH(1,"已推送"),
        REFUND(2,"已退款");

        private Integer code;

        private String desc;

        public Integer getCode() {
            return code;
        }

        public void setCode(Integer code) {
            this.code = code;
        }

        public String getDesc() {
            return desc;
        }

        public void setDesc(String desc) {
            this.desc = desc;
        }

        private StateEnum(Integer code,String desc) {
            this.code = code;
            this.desc = desc;
        }
    }


    /**
     * 查询指定下标 位状态
     * @param complexState 位状态
     * @param index 指定下标
     * @return
     */
    public static int queryBinaryState(final int complexState, final int index) {
        return (complexState >> index) & 1;
    }

    /**
     * 设置指定下标 位状态
     * @param complexState 位状态
     * @param index 指定下标
     * @return
     */
    public static int setBinaryOpen(final int complexState, final int index) {
        return (complexState | 1 << index);
    }


    /**
     * 清除指定下标位状态
     * @param complexState 位状态
     * @param index 指定下标
     * @return
     */
    public static int clearBinaryOpen(int complexState,final int index){
        complexState &= ~(1 << index);
        return complexState;
    }

    /**
     * 验证复合状态是否Ok
     * @param complexState
     * @param stateEnum
     * @return
     */
    public static boolean isOk(int complexState, StateEnum stateEnum) {
        return queryBinaryState(complexState, stateEnum.code) > 0;
    }

    /**
     * 设置复合状态
     * @param complexState
     * @param stateEnum
     * @return
     */
    public static int setOk(int complexState, StateEnum stateEnum) {
        return setBinaryOpen(complexState, stateEnum.code);
    }
}

测试类：

单元测试

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package com.songsy.springboot.test.service.util;

import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * 二进制复合状态工具类
 * @author songshuiyang
 * @date 2023/5/2 12:57
 */
public class BinaryStateUtilsTest {

    private static final Logger LOGGER = LoggerFactory.getLogger(BinaryStateUtilsTest.class);


    @Test
    public void test1() {
        LOGGER.info("0001 {}", BinaryStateUtils.isOk(1, BinaryStateUtils.StateEnum.ORDER));
        LOGGER.info("0010 {}", BinaryStateUtils.isOk(2, BinaryStateUtils.StateEnum.PUSH));
        LOGGER.info("0100 {}", BinaryStateUtils.isOk(4, BinaryStateUtils.StateEnum.REFUND));
    }


    @Test
    public void test2() {
        LOGGER.info("最开始状态 -----------------------");
        int complexState = 0;
        LOGGER.info("下单状态:{} 推送状态:{} 退款状态:{}",
                BinaryStateUtils.isOk(complexState, BinaryStateUtils.StateEnum.ORDER),
                BinaryStateUtils.isOk(complexState, BinaryStateUtils.StateEnum.PUSH),
                BinaryStateUtils.isOk(complexState, BinaryStateUtils.StateEnum.REFUND));

        LOGGER.info("然后用户下单了 -----------------------");
        complexState = BinaryStateUtils.setOk(complexState, BinaryStateUtils.StateEnum.ORDER);
        LOGGER.info("下单状态:{} 推送状态:{} 退款状态:{}",
                BinaryStateUtils.isOk(complexState, BinaryStateUtils.StateEnum.ORDER),
                BinaryStateUtils.isOk(complexState, BinaryStateUtils.StateEnum.PUSH),
                BinaryStateUtils.isOk(complexState, BinaryStateUtils.StateEnum.REFUND));


        LOGGER.info("然后用户退款了 -----------------------");
        complexState = BinaryStateUtils.setOk(complexState, BinaryStateUtils.StateEnum.REFUND);
        LOGGER.info("下单状态:{} 推送状态:{} 退款状态:{}",
                BinaryStateUtils.isOk(complexState, BinaryStateUtils.StateEnum.ORDER),
                BinaryStateUtils.isOk(complexState, BinaryStateUtils.StateEnum.PUSH),
                BinaryStateUtils.isOk(complexState, BinaryStateUtils.StateEnum.REFUND));

    }
}

输出结果

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13:19:44.676 [main] INFO com.songsy.springboot.test.service.util.BinaryStateUtilsTest - 最开始状态 -----------------------
13:19:44.680 [main] INFO com.songsy.springboot.test.service.util.BinaryStateUtilsTest - 下单状态:false 推送状态:false 退款状态:false
13:19:44.681 [main] INFO com.songsy.springboot.test.service.util.BinaryStateUtilsTest - 然后用户下单了 -----------------------
13:19:44.681 [main] INFO com.songsy.springboot.test.service.util.BinaryStateUtilsTest - 下单状态:true 推送状态:false 退款状态:false
13:19:44.682 [main] INFO com.songsy.springboot.test.service.util.BinaryStateUtilsTest - 然后用户退款了 -----------------------
13:19:44.682 [main] INFO com.songsy.springboot.test.service.util.BinaryStateUtilsTest - 下单状态:true 推送状态:false 退款状态:true

总结

  • 利用位运算可以很方便的存放状态，数据库只需存放一个字段，可有效减少过多的变量定义或过多的表字段