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"),
INNER*("内蒙古", "Inner*"),
NINGXIA("宁夏", "Ningxia"),
QINGHAI("青海", "Qinghai"),
SHAANXI("陕西", "Shaanxi"),
GANSU("甘肃", "Gansu"),
SINKIANG("*", "Sinkiang"),
SICHUAN("四川", "Sichuan"),
GUIZHOU("贵州", "Guizhou"),
YUNNAN("云南", "Yunnan"),
CHONGQING("重庆", "Chongqing"),
TIBET("*", "Tibet"),
LIAONING("辽宁", "Liaoning"),
JILIN("吉林", "Jilin"),
HEILONGJIANG("黑龙江", "Heilongjiang"),
HONGKONG("香港", "Hongkong"),
MACAO("澳门", "Macao"),
*("*", "*"),
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 inner*;
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;
/**
* *
*/
private Integer tibet;
private Integer liaoning;
private Integer jilin;
private Integer heilongjiang;
private Integer hongkong;
/**
* 澳门
*/
private Integer macao;
private Integer *;
/**
* 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 getInner*() {
return inner*;
}
public void setInner*(Integer inner*) {
this.inner* = inner*;
}
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 get*() {
return *;
}
public void set*(Integer *) {
this.* = *;
}
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 addInner*() {
this.inner* = this.inner* + 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;
}
/**
* *+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;
}
/**
* *+1
*
*/
public void add*() {
this.* = this.* + 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);