Guava动态调用方法

前言

大家在Coding的时候，经常会遇到这样一个情况，根据不同的条件去执行对应的代码。我们通常的处理方式是利用if-else判断，或者直接switch-case,特别是jdk1.6之后，swith开始支持判断String类型了。

但是如果有几十种情况上百种情况，用if-else来处理这段逻辑，代码看着特别不舒服。

解决这个麻烦有好几种办法，比如自定义注解、Spring结合策略模式、反射或者枚举。

下面分享一下使用Guava工具类通过反射动态调用方法。

业务描述

插座统计：数据库每添加一个插座实例，都统计一下这个插座属于中国哪个省份（细节不重要）

pom.xml

添加工具依赖

<dependency>
    <groupId>com.google.guava</groupId>
    <artifactId>guava</artifactId>
    <version>20.0</version>
</dependency>

ProvinceEnum.java

前端传过来的是中文，需要获取对应的英文名，然后通过拼接的方式生成方法名。

 public enum ProvinceEnum {

     SHANDONG("山东", "Shandong"),

     SHANGHAI("上海", "Shanghai"),

     ZHEJIANG("浙江", "Zhejiang"),

     ANHUI("安徽", "Anhui"),

     FUJIAN("福建", "Fujian"),

     JIANGXI("江西", "Jiangxi"),

     GUANGDONG("广东", "Guangdong"),

     GUANGXI("广西", "Guangxi"),

     HAINAN("海南", "Hainan"),

     HENAN("河南", "Henan"),

     HUNAN("湖南", "Hunan"),

     HUBEI("湖北", "Hubei"),

     BEIJING("北京", "Beijing"),

     TIANJIN("天津", "Tianjin"),

     HEBEI("河北", "Hebei"),

     SHANXI("山西", "Shanxi"),

     INNERMONGOLIA("内蒙古", "Innermongolia"),

     NINGXIA("宁夏", "Ningxia"),

     QINGHAI("青海", "Qinghai"),

     SHAANXI("陕西", "Shaanxi"),

     GANSU("甘肃", "Gansu"),

     SINKIANG("新疆", "Sinkiang"),

     SICHUAN("四川", "Sichuan"),

     GUIZHOU("贵州", "Guizhou"),

     YUNNAN("云南", "Yunnan"),

     CHONGQING("重庆", "Chongqing"),

     TIBET("西藏", "Tibet"),

     LIAONING("辽宁", "Liaoning"),

     JILIN("吉林", "Jilin"),

     HEILONGJIANG("黑龙江", "Heilongjiang"),

     HONGKONG("香港", "Hongkong"),

     MACAO("澳门", "Macao"),

     TAIWAN("台湾", "Taiwan"),

     JIANGSU("江苏", "Jiangsu");

     private String code;

     private String msg;

     private ProvinceEnum(String code, String msg) {
         this.code = code;
         this.msg = msg;
     }

     public String getCode() {
         return code;
     }

     public String getMsg() {
         return msg;
     }

     public static String getMsgByCode(String code) {
         String msg = null;
         for (ProvinceEnum e : ProvinceEnum.values()) {
             if (e.getCode().equals(code)) {
                 msg = e.getMsg();
                 break;
             }
         }
         return msg;
     }

 }

点击展开

SocketStatistics.java

实体类，统计的对象

 public class SocketStatistics {
     /**
      * 主键自增长
      */
     private Long pid;

     private Integer shandong;

     private Integer jiangsu;

     private Integer shanghai;

     private Integer zhejiang;

     private Integer anhui;

     private Integer fujian;

     private Integer jiangxi;

     private Integer guangdong;

     private Integer guangxi;

     private Integer hainan;

     private Integer henan;

     private Integer hunan;

     private Integer hubei;

     private Integer beijing;

     private Integer tianjin;

     private Integer hebei;

     private Integer shanxi;

     /**
      * 内蒙古
      */
     private Integer innermongolia;

     private Integer ningxia;

     private Integer qinghai;

     /**
      * 陕西
      */
     private Integer shaanxi;

     private Integer gansu;

     private Integer sinkiang;

     private Integer sichuan;

     private Integer guizhou;

     private Integer yunnan;

     private Integer chongqing;

     /**
      * 西藏
      */
     private Integer tibet;

     private Integer liaoning;

     private Integer jilin;

     private Integer heilongjiang;

     private Integer hongkong;

     /**
      * 澳门
      */
     private Integer macao;

     private Integer taiwan;

     /**
      * 在线数量
      */
     private Integer online;

     /**
      * 离线数量
      */
     private Integer outline;

     public Long getPid() {
         return pid;
     }

     public void setPid(Long pid) {
         this.pid = pid;
     }

     public Integer getShandong() {
         return shandong;
     }

     public void setShandong(Integer shandong) {
         this.shandong = shandong;
     }

     public Integer getJiangsu() {
         return jiangsu;
     }

     public void setJiangsu(Integer jiangsu) {
         this.jiangsu = jiangsu;
     }

     public Integer getShanghai() {
         return shanghai;
     }

     public void setShanghai(Integer shanghai) {
         this.shanghai = shanghai;
     }

     public Integer getZhejiang() {
         return zhejiang;
     }

     public void setZhejiang(Integer zhejiang) {
         this.zhejiang = zhejiang;
     }

     public Integer getAnhui() {
         return anhui;
     }

     public void setAnhui(Integer anhui) {
         this.anhui = anhui;
     }

     public Integer getFujian() {
         return fujian;
     }

     public void setFujian(Integer fujian) {
         this.fujian = fujian;
     }

     public Integer getJiangxi() {
         return jiangxi;
     }

     public void setJiangxi(Integer jiangxi) {
         this.jiangxi = jiangxi;
     }

     public Integer getGuangdong() {
         return guangdong;
     }

     public void setGuangdong(Integer guangdong) {
         this.guangdong = guangdong;
     }

     public Integer getGuangxi() {
         return guangxi;
     }

     public void setGuangxi(Integer guangxi) {
         this.guangxi = guangxi;
     }

     public Integer getHainan() {
         return hainan;
     }

     public void setHainan(Integer hainan) {
         this.hainan = hainan;
     }

     public Integer getHenan() {
         return henan;
     }

     public void setHenan(Integer henan) {
         this.henan = henan;
     }

     public Integer getHunan() {
         return hunan;
     }

     public void setHunan(Integer hunan) {
         this.hunan = hunan;
     }

     public Integer getHubei() {
         return hubei;
     }

     public void setHubei(Integer hubei) {
         this.hubei = hubei;
     }

     public Integer getBeijing() {
         return beijing;
     }

     public void setBeijing(Integer beijing) {
         this.beijing = beijing;
     }

     public Integer getTianjin() {
         return tianjin;
     }

     public void setTianjin(Integer tianjin) {
         this.tianjin = tianjin;
     }

     public Integer getHebei() {
         return hebei;
     }

     public void setHebei(Integer hebei) {
         this.hebei = hebei;
     }

     public Integer getShanxi() {
         return shanxi;
     }

     public void setShanxi(Integer shanxi) {
         this.shanxi = shanxi;
     }

     public Integer getInnermongolia() {
         return innermongolia;
     }

     public void setInnermongolia(Integer innermongolia) {
         this.innermongolia = innermongolia;
     }

     public Integer getNingxia() {
         return ningxia;
     }

     public void setNingxia(Integer ningxia) {
         this.ningxia = ningxia;
     }

     public Integer getQinghai() {
         return qinghai;
     }

     public void setQinghai(Integer qinghai) {
         this.qinghai = qinghai;
     }

     public Integer getShaanxi() {
         return shaanxi;
     }

     public void setShaanxi(Integer shaanxi) {
         this.shaanxi = shaanxi;
     }

     public Integer getGansu() {
         return gansu;
     }

     public void setGansu(Integer gansu) {
         this.gansu = gansu;
     }

     public Integer getSinkiang() {
         return sinkiang;
     }

     public void setSinkiang(Integer sinkiang) {
         this.sinkiang = sinkiang;
     }

     public Integer getSichuan() {
         return sichuan;
     }

     public void setSichuan(Integer sichuan) {
         this.sichuan = sichuan;
     }

     public Integer getGuizhou() {
         return guizhou;
     }

     public void setGuizhou(Integer guizhou) {
         this.guizhou = guizhou;
     }

     public Integer getYunnan() {
         return yunnan;
     }

     public void setYunnan(Integer yunnan) {
         this.yunnan = yunnan;
     }

     public Integer getChongqing() {
         return chongqing;
     }

     public void setChongqing(Integer chongqing) {
         this.chongqing = chongqing;
     }

     public Integer getTibet() {
         return tibet;
     }

     public void setTibet(Integer tibet) {
         this.tibet = tibet;
     }

     public Integer getLiaoning() {
         return liaoning;
     }

     public void setLiaoning(Integer liaoning) {
         this.liaoning = liaoning;
     }

     public Integer getJilin() {
         return jilin;
     }

     public void setJilin(Integer jilin) {
         this.jilin = jilin;
     }

     public Integer getHeilongjiang() {
         return heilongjiang;
     }

     public void setHeilongjiang(Integer heilongjiang) {
         this.heilongjiang = heilongjiang;
     }

     public Integer getHongkong() {
         return hongkong;
     }

     public void setHongkong(Integer hongkong) {
         this.hongkong = hongkong;
     }

     public Integer getMacao() {
         return macao;
     }

     public void setMacao(Integer macao) {
         this.macao = macao;
     }

     public Integer getTaiwan() {
         return taiwan;
     }

     public void setTaiwan(Integer taiwan) {
         this.taiwan = taiwan;
     }

     public Integer getOnline() {
         return online;
     }

     public void setOnline(Integer online) {
         this.online = online;
     }

     public Integer getOutline() {
         return outline;
     }

     public void setOutline(Integer outline) {
         this.outline = outline;
     }

     public void addTibet() {
         this.tibet = this.tibet + 1;
     }

     /**
      * 山东+1
      *
      */
     public void addShandong() {
         this.shandong = this.shandong + 1;
     }

     /**
      * 江苏+1
      *
      */
     public void addJiangsu() {
         this.jiangsu = this.jiangsu + 1;
     }

     /**
      * 上海+1
      *
      */
     public void addShanghai() {
         this.shanghai = this.shanghai + 1;
     }

     /**
      * 浙江+1
      *
      */
     public void addZhejiang() {
         this.zhejiang = this.zhejiang + 1;
     }

     /**
      * 安徽+1
      *
      */
     public void addAnhui() {
         this.anhui = this.anhui + 1;
     }

     /**
      * 福建+1
      *
      */
     public void addFujian() {
         this.fujian = this.fujian + 1;
     }

     /**
      * 江西+1
      *
      */
     public void addJiangxi() {
         this.jiangxi = this.jiangxi + 1;
     }

     /**
      * 广东+1
      *
      */
     public void addGuangdong() {
         this.guangdong = this.guangdong + 1;
     }

     /**
      * 广西+1
      *
      */
     public void addGuangxi() {
         this.guangxi = this.guangxi + 1;
     }

     /**
      * 海南+1
      *
      */
     public void addHainan() {
         this.hainan = this.hainan + 1;
     }

     /**
      * 河南+1
      *
      */
     public void addHenan() {
         this.henan = this.henan + 1;
     }

     /**
      * 湖南+1
      *
      */
     public void addHunan() {
         this.hunan = this.hunan + 1;
     }

     /**
      * 湖北+1
      *
      */
     public void addHubei() {
         this.hubei = this.hubei + 1;
     }

     /**
      * 北京+1
      *
      */
     public void addBeijing() {
         this.beijing = this.beijing + 1;
     }

     /**
      * 天津+1
      *
      */
     public void addTianjin() {
         this.tianjin = this.tianjin + 1;
     }

     /**
      * 河北+1
      *
      */
     public void addHebei() {
         this.hebei = this.hebei + 1;
     }

     /**
      * 山西+1
      *
      */
     public void addShanxi() {
         this.shanxi = this.shanxi + 1;
     }

     /**
      * 陕西+1
      *
      */
     public void addShaanxi() {
         this.shaanxi = this.shaanxi + 1;
     }

     /**
      * 内蒙古+1
      *
      */
     public void addInnermongolia() {
         this.innermongolia = this.innermongolia + 1;
     }

     /**
      * 宁夏+1
      *
      */
     public void addNingxia() {
         this.ningxia = this.ningxia + 1;
     }

     /**
      * 青海+1
      *
      */
     public void addQinghai() {
         this.qinghai = this.qinghai + 1;
     }

     /**
      * 甘肃+1
      *
      */
     public void addGansu() {
         this.gansu = this.gansu + 1;
     }

     /**
      * 新疆+1
      *
      */
     public void addSinkiang() {
         this.sinkiang = this.sinkiang + 1;
     }

     /**
      * 四川+1
      *
      */
     public void addSichuan() {
         this.sichuan = this.sichuan + 1;
     }

     /**
      * 贵州+1
      *
      */
     public void addGuizhou() {
         this.guizhou = this.guizhou + 1;
     }

     /**
      * 云南+1
      *
      */
     public void addYunnan() {
         this.yunnan = this.yunnan + 1;
     }

     /**
      * 重庆+1
      *
      */
     public void addChongqing() {
         this.chongqing = this.chongqing + 1;
     }

     /**
      * 辽宁+1
      *
      */
     public void addLiaoning() {
         this.liaoning = this.liaoning + 1;
     }

     /**
      * 吉林+1
      *
      */
     public void addJilin() {
         this.jilin = this.jilin + 1;
     }

     /**
      * 黑龙江+1
      *
      */
     public void addHeilongjiang() {
         this.heilongjiang = this.heilongjiang + 1;
     }

     /**
      * 香港+1
      *
      */
     public void addHongkong() {
         this.hongkong = this.hongkong + 1;
     }

     /**
      * 澳门+1
      *
      */
     public void addMacao() {
         this.macao = this.macao + 1;
     }

     /**
      * 台湾+1
      *
      */
     public void addTaiwan() {
         this.taiwan = this.taiwan + 1;
     }
 }

点击展开

service层逻辑

// 从数据库中取出插座统计记录，该表中只有一条记录，如有变化直接更新就是
        SocketStatistics socketStatistics = socketStatisticsMapper.selectOne();

        // 根据前端传过来的插座所属省份中文名，到省份枚举类中得到对应的英文名
        // 再通过拼接的方式得到对应的方法名
        String methodName = "add"
                + ProvinceEnum.getMsgByCode(socket.getProvince());

        // 到SocketStatistics类中找到这个方法
        Method method = SocketStatistics.class.getDeclaredMethod(methodName);

        // Guava的工具类通过反射，动态调用该方法
        Invokable<SocketStatistics, Object> invokable = (Invokable<SocketStatistics, Object>) Invokable
                .from(method);
        invokable.invoke(socketStatistics);

        // 数据处理完后，更新数据库
        socketStatisticsMapper.updateByPrimaryKeySelective(socketStatistics);