@Service
@Transactional
public class DemoSerivce {
   //SUPPORTED 若無(wú)事務(wù)傳播則默認(rèn)不會(huì)有事務(wù),若有事務(wù)傳播則會(huì)開啟事務(wù)
   @Transactional(propagation = Propagation.SUPPORTED)
   public int getValue(){
      return 0;
   }
   //默認(rèn)開啟事務(wù)（由類上的@Transactional決定的）
   public int getValueWithTx(){
      return 0;
   }
    @Transactional(propagation = Propagation.NOT_SUPPORTED)
   public int getValueWithoutTx(){
      return 0;
   }
}

public class DemoService{
    public int getValue(){
        return 666;
    }
    public DemoService getReal(){
        //這里的this指向的就是當(dāng)前的自己，并非代理對(duì)象
        return this;
    }
}
public class DemoServiceProxy{
    private DemoService target;
    public DemoServiceProxy(DemoService target){
        this.target=target;
    }
    public int getValue(){
        //增強(qiáng)：開啟事務(wù)
        return  target.getValue()+222;
        //增強(qiáng)：提交事務(wù)
    }
    public DemoService getReal(){
        //這里就會(huì)間接的把原生的對(duì)象傳遞返回
        return target.getReal();
    }
}
    public static void main(String[] args) {
        DemoServiceProxy proxy=new DemoServiceProxy(new DemoService());
        System.out.println("proxy class:" +proxy.getClass().getName());
        System.out.println("real class:" +proxy.getReal().getClass().getName());
        System.out.println("proxy getValue result:" + proxy.getValue() );
        System.out.println("real getValue result:" + proxy.getReal().getValue() );
    }

/**
 * @author zuowenjun
 * @date 2022/12/5 22:03
 * @description 可代理BEAN訪問者接口（支持獲取代理的真實(shí)對(duì)象、獲取代理對(duì)象）
 */
public interface ProxyableBeanAccessor<T extends ProxyableBeanAccessor> extends RawTargetAccess {
    String CONTEXT_KEY_REAL_GET = "proxyable_bean_accessor_real_get";
    /**
     * 獲取代理的真實(shí)對(duì)象（即：未被代理的對(duì)象）
     * 注：若調(diào)用未被代理的bean的公開方法，則均不會(huì)再走AOP切面
     *
     * @return 未被代理的對(duì)象Bean
     */
    @SuppressWarnings("unchecked")
    @Transactional(propagation = Propagation.NOT_SUPPORTED)
    default T getReal() {
        return (T) this;
    }
    /**
     * 獲取當(dāng)前類的代理對(duì)象（即：已被代理的對(duì)象）
     * 注：若調(diào)用已被代理的對(duì)象Bean的公開方法，則相關(guān)AOP切面均可正常攔截與執(zhí)行
     *
     * @return 已被代理的對(duì)象Bean
     */
    @SuppressWarnings("unchecked")
    @Transactional(propagation = Propagation.NOT_SUPPORTED)
    default T getProxy() {
        return (T) SpringUtils.getBean(this.getClass());
    }
    /**
     * 將當(dāng)前BEAN轉(zhuǎn)換為代理對(duì)象或真實(shí)對(duì)象
     *
     * @param realGet 是否轉(zhuǎn)換獲取真實(shí)對(duì)象
     * @return 未被代理的對(duì)象Bean OR 已被代理的對(duì)象Bean
     */
    @Transactional(propagation = Propagation.NOT_SUPPORTED)
    default T selfAs(Supplier<Boolean> realGet) {
        Boolean needGetReal = false;
        if (realGet == null) {
            if (ContextUtils.get() != null) {
                needGetReal = (Boolean) ContextUtils.get().getGlobalVariableMap().getOrDefault(CONTEXT_KEY_REAL_GET, false);
            }
        } else {
            needGetReal = realGet.get();
        }
        return Boolean.TRUE.equals(needGetReal) ? getReal() : getProxy();
    }
}

public SpringUtils implements ApplicationContextAware{
private static ApplicationContext context;
    @Override
    public void setApplicationContext(ApplicationContext applicationContext)
            throws BeansException {
        context=applicationContext;
    }
  public static <T> getBean(Class<T> clazz){
     return context.getBean(clazz);
   }
}

//serive BEAN定義
@Service
@Transactional
public class DemoService implements ProxyableBeanAccessor<DemoService> {
   ... ...
    public Demo selectByMergerParam(Demo demo){
       return getMapper().selectByMergerParam(demo);
    }
    @Transactional(propagation = Propagation.NOT_SUPPORTED)
    public Demo selectByMergerParam2(Demo demo){
        //通過getProxy獲取當(dāng)前類的代理BEAN，以便可以執(zhí)行事務(wù)切面
        return getProxy().doSelectByMergerParam(demo);
    }
    public Demo doSelectByMergerParam(Demo demo){
        return getMapper().selectByMergerParam(demo);
    }
}
//具體使用:
    @Autowired
    private DemoService demoService;
            Demo query = new Demo ();
            query.setWaybillNumber("123455667");
            //示例一：獲取原生對(duì)象查詢，由于沒有代理，則無(wú)事務(wù)
            demoService.getReal().selectByMergerParam(query);
            //示例二：根據(jù)LAMBDA表達(dá)式的布爾值來(lái)決定是否獲取原生或代理（這里演示：如果是TIDB，則獲取原生對(duì)象，即：不開事務(wù)）
            demoService.selfAs(()-> TidbDataSourceSwitcher.isUsingTidbDataSource()).selectByMergerParam(query);
            //示例三：根據(jù)線程上下文設(shè)置的布爾值來(lái)決定是否獲取原生或代理（這里演示：如果是TIDB，則獲取原生對(duì)象，即：不開事務(wù)），這種方式主要是為了簡(jiǎn)化大批量的動(dòng)態(tài)邏輯判斷的場(chǎng)景，
            // 一次設(shè)置同線程的所有ProxyableBeanAccessor的子類的selfAs(null)均可自動(dòng)判斷
            ContextUtils.get().addGlobalVariable(ProxyableBeanAccessor.CONTEXT_KEY_REAL_GET,TidbDataSourceSwitcher.isUsingTidbDataSource());
            demoService.selfAs(null).selectByMergerParam(query);
            //示例四：獲取代理對(duì)象，一般用于BEAN內(nèi)部方法之間調(diào)用，外部調(diào)用其實(shí)本身就是代理無(wú)意義
            demoService.getProxy().selectByMergerParam(query);