package com.company.controller; 
import com.company.service.CalculateService;
import com.company.service.TestService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController; 
@RestController
public class TestController {
 
 @Autowired
 private TestService testService;
 
 @Autowired
 private CalculateService calculateService;
 
 @RequestMapping("/test")
 public String getHello() {
 String testList = testService.getList("code123","name456");
 String calculateResult = calculateService.getResult("測(cè)試");
 return (testList + "," +calculateResult);
 }
}

package com.company.handler; 
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor;
import org.springframework.beans.factory.support.GenericBeanDefinition;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ResourceLoaderAware;
import org.springframework.core.env.Environment;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternUtils;
import org.springframework.core.type.classreading.CachingMetadataReaderFactory;
import org.springframework.core.type.classreading.MetadataReader;
import org.springframework.core.type.classreading.MetadataReaderFactory;
import org.springframework.stereotype.Component;
import org.springframework.util.ClassUtils; 
import java.io.IOException;
import java.util.LinkedHashSet;
import java.util.Set;
 
/**
 * 用于Spring動(dòng)態(tài)注入自定義接口
 * @author lichuang
 */
@Component
public class ServiceBeanDefinitionRegistry implements BeanDefinitionRegistryPostProcessor,ResourceLoaderAware,ApplicationContextAware { 
 @Override
 public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {
 //這里一般我們是通過反射獲取需要代理的接口的clazz列表
 //比如判斷包下面的類，或者通過某注解標(biāo)注的類等等
 Set<Class<?>> beanClazzs = scannerPackages("com.company.service");
 for (Class beanClazz : beanClazzs) {
  BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(beanClazz);
  GenericBeanDefinition definition = (GenericBeanDefinition) builder.getRawBeanDefinition();
 
  //在這里，我們可以給該對(duì)象的屬性注入對(duì)應(yīng)的實(shí)例。
  //比如mybatis，就在這里注入了dataSource和sqlSessionFactory，
  // 注意，如果采用definition.getPropertyValues()方式的話，
  // 類似definition.getPropertyValues().add("interfaceType", beanClazz);
  // 則要求在FactoryBean（本應(yīng)用中即ServiceFactory）提供setter方法，否則會(huì)注入失敗
  // 如果采用definition.getConstructorArgumentValues()，
  // 則FactoryBean中需要提供包含該屬性的構(gòu)造方法，否則會(huì)注入失敗
  definition.getConstructorArgumentValues().addGenericArgumentValue(beanClazz);
 
  //注意，這里的BeanClass是生成Bean實(shí)例的工廠，不是Bean本身。
  // FactoryBean是一種特殊的Bean，其返回的對(duì)象不是指定類的一個(gè)實(shí)例，
  // 其返回的是該工廠Bean的getObject方法所返回的對(duì)象。
  definition.setBeanClass(ServiceFactory.class);
 
  //這里采用的是byType方式注入，類似的還有byName等
  definition.setAutowireMode(GenericBeanDefinition.AUTOWIRE_BY_TYPE);
  registry.registerBeanDefinition(beanClazz.getSimpleName(), definition);
 }
 }
 
 private static final String DEFAULT_RESOURCE_PATTERN = "**/*.class"; 
 private MetadataReaderFactory metadataReaderFactory;
 
 /**
 * 根據(jù)包路徑獲取包及子包下的所有類
 * @param basePackage basePackage
 * @return Set<Class<?>> Set<Class<?>>
 */
 private Set<Class<?>> scannerPackages(String basePackage) {
 Set<Class<?>> set = new LinkedHashSet<>();
 String packageSearchPath = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX +
  resolveBasePackage(basePackage) + '/' + DEFAULT_RESOURCE_PATTERN;
 try {
  Resource[] resources = this.resourcePatternResolver.getResources(packageSearchPath);
  for (Resource resource : resources) {
  if (resource.isReadable()) {
   MetadataReader metadataReader = this.metadataReaderFactory.getMetadataReader(resource);
   String className = metadataReader.getClassMetadata().getClassName();
   Class<?> clazz;
   try {
   clazz = Class.forName(className);
   set.add(clazz);
   } catch (ClassNotFoundException e) {
   e.printStackTrace();
   }
  }
  }
 } catch (IOException e) {
  e.printStackTrace();
 }
 return set;
 }
 
 protected String resolveBasePackage(String basePackage) {
 return ClassUtils.convertClassNameToResourcePath(this.getEnvironment().resolveRequiredPlaceholders(basePackage));
 }
 
 @Override
 public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
 
 }
 
 private ResourcePatternResolver resourcePatternResolver; 
 private ApplicationContext applicationContext;
 
 @Override
 public void setResourceLoader(ResourceLoader resourceLoader) {
 this.resourcePatternResolver = ResourcePatternUtils.getResourcePatternResolver(resourceLoader);
 this.metadataReaderFactory = new CachingMetadataReaderFactory(resourceLoader);
 }
 
 @Override
 public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
 this.applicationContext = applicationContext;
 }
 
 private Environment getEnvironment() {
 return applicationContext.getEnvironment();
 }
}

package com.company.handler; 
import org.springframework.beans.factory.FactoryBean; 
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Proxy;
 
/**
 * 接口實(shí)例工廠，這里主要是用于提供接口的實(shí)例對(duì)象
 * @author lichuang
 * @param <T>
 */
public class ServiceFactory<T> implements FactoryBean<T> { 
 private Class<T> interfaceType; 
 public ServiceFactory(Class<T> interfaceType) {
 this.interfaceType = interfaceType;
 }
 
 @Override
 public T getObject() throws Exception {
 //這里主要是創(chuàng)建接口對(duì)應(yīng)的實(shí)例，便于注入到spring容器中
 InvocationHandler handler = new ServiceProxy<>(interfaceType);
 return (T) Proxy.newProxyInstance(interfaceType.getClassLoader(),
  new Class[] {interfaceType},handler);
 }
 
 @Override
 public Class<T> getObjectType() {
 return interfaceType;
 }
 
 @Override
 public boolean isSingleton() {
 return true;
 }
}

package com.company.handler; 
import com.alibaba.fastjson.JSON; 
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.util.Arrays;
 
/**
 * 動(dòng)態(tài)代理，需要注意的是，這里用到的是JDK自帶的動(dòng)態(tài)代理，代理對(duì)象只能是接口，不能是類
 * @author lichuang
 */
 
public class ServiceProxy<T> implements InvocationHandler { 
 private Class<T> interfaceType; 
 public ServiceProxy(Class<T> intefaceType) {
 this.interfaceType = interfaceType;
 }
 
 @Override
 public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
 if (Object.class.equals(method.getDeclaringClass())) {
  return method.invoke(this,args);
 }
 System.out.println("調(diào)用前，參數(shù)：{}" + args);
 //這里可以得到參數(shù)數(shù)組和方法等，可以通過反射，注解等，進(jìn)行結(jié)果集的處理
 //mybatis就是在這里獲取參數(shù)和相關(guān)注解，然后根據(jù)返回值類型，進(jìn)行結(jié)果集的轉(zhuǎn)換
 Object result = JSON.toJSONString(args);
 System.out.println("調(diào)用后，結(jié)果：{}" + result);
 return result;
 }
}

package com.company.service; 
public interface CalculateService { 
 String getResult(String name);
}

package com.company.service; 
public interface TestService { 
 String getList(String code, String name);
}

package com.kfit.demo.service;
public class TestService {
 private String name;
 public String getName() {
 return name;
 }
 public void setName(String name) {
 this.name = name;
 }
 public void print(){
 System.out.println("動(dòng)態(tài)載入bean,name="+name);
 }
}

//獲取context. 
ApplicationContext ctx = (ApplicationContext) SpringApplication.run(App.class, args);
 
//獲取BeanFactory
DefaultListableBeanFactory defaultListableBeanFactory = (DefaultListableBeanFactory)ctx.getAutowireCapableBeanFactory();
 
//創(chuàng)建bean信息
BeanDefinitionBuilderbeanDefinitionBuilder =BeanDefinitionBuilder.genericBeanDefinition(TestService.class);
beanDefinitionBuilder.addPropertyValue("name","張三");
 
//動(dòng)態(tài)注冊(cè)bean
defaultListableBeanFactory.registerBeanDefinition("testService",beanDefinitionBuilder.getBeanDefinition());
 
//獲取動(dòng)態(tài)注冊(cè)的bean
TestService testService =ctx.getBean(TestService.class);
testService.print();

動(dòng)態(tài)載入bean,name=張三

beanDefinitionBuilder = BeanDefinitionBuilder.genericBeanDefinition(TestService.class);
beanDefinitionBuilder.addPropertyValue("name","李四");
defaultListableBeanFactory.registerBeanDefinition("testService", beanDefinitionBuilder.getBeanDefinition());

動(dòng)態(tài)載入bean,name=李四

beanDefinitionBuilder = BeanDefinitionBuilder.genericBeanDefinition(TestService.class);
beanDefinitionBuilder.addPropertyValue("name","李四");
defaultListableBeanFactory.registerBeanDefinition("testService1",beanDefinitionBuilder.getBeanDefinition());
TestService testService =ctx.getBean(TestService.class);
testService.print();

TestService testService =ctx.getBean("testService");

applicationContext.getAutowireCapableBeanFactory().applyBeanPostProcessorsAfterInitialization(obj, obj.getClass().getName());
beanFactory.registerSingleton(obj.getClass().getName(), obj);

 //刪除bean.
defaultListableBeanFactory.removeBeanDefinition("testService");