\u4e0d\u8fc7\u4ece Spring5 \u5f00\u59cb\uff0c\u5728 AbstractBeandefinition \u7c7b\u4e2d\u591a\u4e86\u4e00\u4e2a\u5c5e\u6027\uff0c\u5bf9\u4e8e\u7279\u6b8a\u7684 Bean \u6211\u4eec\u6709\u4e86\u66f4\u591a\u7684\u9009\u62e9\uff1a<\/p>\n
\/**\n * Specify a callback for creating an instance of the bean,\n * as an alternative to a declaratively specified factory method.\n * <p>If such a callback is set, it will override any other constructor\n * or factory method metadata. However, bean property population and\n * potential annotation-driven injection will still apply as usual.\n * @since 5.0\n * @see #setConstructorArgumentValues(ConstructorArgumentValues)\n * @see #setPropertyValues(MutablePropertyValues)\n *\/\npublic void setInstanceSupplier(@Nullable Supplier<?> instanceSupplier) {\n this.instanceSupplier = instanceSupplier;\n}\n\n\/**\n * Return a callback for creating an instance of the bean, if any.\n * @since 5.0\n *\/\n@Nullable\npublic Supplier<?> getInstanceSupplier() {\n return this.instanceSupplier;\n}<\/code><\/pre>\n\u63a5\u4e0b\u6765\u677e\u54e5\u5c31\u6765\u548c\u5927\u5bb6\u7b80\u5355\u804a\u4e00\u804a\u8fd9\u4e2a\u8bdd\u9898\u3002<\/p>\n
1. \u4f20\u7edf\u89e3\u51b3\u65b9\u6848<\/h2>\n1.1 \u95ee\u9898<\/h3>\n
\u4e0d\u77e5\u9053\u5404\u4f4d\u5c0f\u4f19\u4f34\u4eec\u6709\u6ca1\u6709\u7528\u8fc7 OkHttp\uff0c\u8fd9\u662f\u4e00\u4e2a\u4e13\u95e8\u505a\u7f51\u7edc\u8bf7\u6c42\u7684\u5de5\u5177\uff0c\u5728\u5fae\u670d\u52a1\u7684 HTTP \u8c03\u7528\u7ec4\u4ef6\u4e2d\uff0c\u6211\u4eec\u53ef\u4ee5\u914d\u7f6e\u5e95\u5c42\u4f7f\u7528 OkHttp \u8fd9\u4e2a\u5de5\u5177\u3002<\/p>\n
\u4e00\u822c\u6765\u8bf4\uff0c\u5982\u679c\u6211\u4eec\u60f3\u76f4\u63a5\u4f7f\u7528 OkHttp\uff0c\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
OkHttpClient client = new OkHttpClient.Builder()\n .connectTimeout(5, TimeUnit.SECONDS)\n .readTimeout(5, TimeUnit.SECONDS)\n .build();\nRequest getReq = new Request.Builder().get().url("http:\/\/www.javaboy.org").build();\nCall call = client.newCall(getReq);\ncall.enqueue(new Callback() {\n @Override\n public void onFailure(@NotNull Call call, @NotNull IOException e) {\n System.out.println("e.getMessage() = " + e.getMessage());\n }\n @Override\n public void onResponse(@NotNull Call call, @NotNull Response response) throws IOException {\n System.out.println("response.body().string() = " + response.body().string());\n }\n});<\/code><\/pre>\n\u5148\u901a\u8fc7\u5efa\u9020\u8005\u6a21\u5f0f\u521b\u5efa\u51fa\u6765\u4e00\u4e2a OkHttpClient \u5bf9\u8c61\uff0c\u7136\u540e\u8fd8\u662f\u5efa\u9020\u8005\u6a21\u5f0f\u521b\u5efa\u51fa\u6765 Request \u5bf9\u8c61\uff0c\u63a5\u4e0b\u6765\u53bb\u53d1\u9001\u8bf7\u6c42\u5c31\u53ef\u4ee5\u4e86\u3002\u90a3\u4e48\u5bf9\u4e8e\u8fd9\u6837\u7684\u4ee3\u7801\uff0c\u6211\u4eec\u53ef\u4ee5\u5c06 OkHttpClient \u5bf9\u8c61\u4ea4\u7531 Spring \u5bb9\u5668\u7edf\u4e00\u7ba1\u7406\uff0c\u90a3\u4e48\u8be5\u5982\u4f55\u5c06 OkHttpClient \u6ce8\u518c\u5230 Spring \u5bb9\u5668\u4e2d\u5462\uff1f<\/p>\n
1.2 \u9759\u6001\u5de5\u5382\u65b9\u6cd5<\/h3>\n
\u9996\u5148\u53ef\u4ee5\u91c7\u7528\u9759\u6001\u5de5\u5382\u65b9\u6cd5\uff0c\u4e5f\u5c31\u662f\u5de5\u5382\u65b9\u6cd5\u662f\u4e00\u4e2a\u9759\u6001\u65b9\u6cd5\uff0c\u5982\u4e0b\uff1a<\/p>\n
public class OkHttpStaticFactory {\n private static OkHttpClient okHttpClient;\n static {\n okHttpClient = new OkHttpClient.Builder()\n .connectTimeout(5, TimeUnit.SECONDS)\n .readTimeout(5, TimeUnit.SECONDS)\n .build();\n }\n \n public static OkHttpClient getOkHttpClient() {\n return okHttpClient;\n }\n}<\/code><\/pre>\n\u7136\u540e\u5728 Spring \u914d\u7f6e\u6587\u4ef6\u4e2d\u8fdb\u884c\u6ce8\u5165\uff1a<\/p>\n
<bean class="org.javaboy.bean.OkHttpStaticFactory" factory-method="getOkHttpClient" id="httpClient"\/><\/code><\/pre>\n\u9759\u6001\u5de5\u5382\u7684\u7279\u70b9\u662f\u9759\u6001\u65b9\u6cd5\u53ef\u4ee5\u76f4\u63a5\u8c03\u7528\uff0c\u5e76\u5fc5\u987b\u8981\u83b7\u53d6\u5230\u5de5\u5382\u7c7b\u7684\u5b9e\u4f8b\uff0c\u6240\u4ee5\u4e0a\u9762\u914d\u7f6e\u7684\u65f6\u5019\u53ea\u9700\u8981\u6307\u5b9a factory-method<\/code> \u5c31\u53ef\u4ee5\u4e86\u3002<\/p>\n\u8fd9\u5c31\u53ef\u4ee5\u4e86\uff0c\u5c06\u6765\u6211\u4eec\u53bb Spring \u5bb9\u5668\u4e2d\u67e5\u627e\u4e00\u4e2a\u540d\u4e3a httpClient \u7684\u5bf9\u8c61\uff0c\u62ff\u5230\u624b\u7684\u5c31\u662f OkHttpClient \u4e86\u3002<\/p>\n
1.3 \u5b9e\u4f8b\u5de5\u5382\u65b9\u6cd5<\/h3>\n
\u5b9e\u4f8b\u5de5\u5382\u65b9\u6cd5\u610f\u601d\u5c31\u662f\u8bf4\u5de5\u5382\u65b9\u6cd5\u662f\u4e00\u4e2a\u5b9e\u4f8b\u65b9\u6cd5\u3002\u5982\u4e0b\uff1a<\/p>\n
public class OkHttpInstanceFactory {\n private volatile static OkHttpClient okHttpClient;\n\n public OkHttpClient getInstance() {\n if (okHttpClient == null) {\n synchronized (OkHttpInstanceFactory.class) {\n if (okHttpClient == null) {\n okHttpClient = new OkHttpClient.Builder()\n .connectTimeout(5, TimeUnit.SECONDS)\n .readTimeout(5, TimeUnit.SECONDS)\n .build();\n }\n }\n }\n return okHttpClient;\n }\n}<\/code><\/pre>\n\u8fd9\u662f\u4e00\u4e2a\u7b80\u5355\u7684\u5355\u4f8b\u6a21\u5f0f\u3002\u4f46\u662f\u8fd9\u91cc\u7684\u5de5\u5382\u65b9\u6cd5\u662f\u4e00\u4e2a\u5b9e\u4f8b\u65b9\u6cd5\uff0c\u5b9e\u4f8b\u65b9\u6cd5\u7684\u8c03\u7528\u5fc5\u987b\u5f97\u5148\u83b7\u53d6\u5230\u5bf9\u8c61\u7136\u540e\u624d\u80fd\u8c03\u7528\u5b9e\u4f8b\u65b9\u6cd5\uff0c\u56e0\u6b64\u914d\u7f6e\u65b9\u5f0f\u5982\u4e0b\uff1a<\/p>\n
<bean class="org.javaboy.bean.OkHttpInstanceFactory" id="httpInstanceFactory"\/>\n<bean factory-bean="httpInstanceFactory" factory-method="getInstance" id="httpClient"\/><\/code><\/pre>\n\u597d\u5566\uff0c\u63a5\u4e0b\u6765\u6211\u4eec\u5c31\u53ef\u4ee5\u53bb Spring \u5bb9\u5668\u4e2d\u83b7\u53d6\u4e00\u4e2a\u540d\u4e3a httpClient \u7684\u5bf9\u8c61\u4e86\uff0c\u62ff\u5230\u624b\u7684\u5c31\u662f OkHttpClient \u5b9e\u4f8b\u3002<\/p>\n
1.4 FactoryBean<\/h3>\n
\u5f53\u7136\uff0c\u4e5f\u53ef\u4ee5\u901a\u8fc7 FactoryBean \u6765\u89e3\u51b3\u4e0a\u8ff0\u95ee\u9898\uff0cFactoryBean \u677e\u54e5\u5728\u4e4b\u524d\u7684\u6587\u7ae0\u4e2d\u521a\u521a\u548c\u5927\u5bb6\u4ecb\u7ecd\u8fc7\uff0c\u6211\u4eec\u6765\u770b\u4e0b\uff1a<\/p>\n
public class OkHttpClientFactoryBean implements FactoryBean<OkHttpClient> {\n @Override\n public OkHttpClient getObject() throws Exception {\n return new OkHttpClient.Builder()\n .connectTimeout(5, TimeUnit.SECONDS)\n .readTimeout(5, TimeUnit.SECONDS)\n .build();\n }\n\n @Override\n public Class<?> getObjectType() {\n return OkHttpClient.class;\n }\n\n @Override\n public boolean isSingleton() {\n return true;\n }\n}<\/code><\/pre>\n\u6700\u540e\u5728 Spring \u4e2d\u914d\u7f6e\u5373\u53ef\uff1a<\/p>\n
<bean class="org.javaboy.bean.OkHttpClientFactoryBean" id="httpClient"\/><\/code><\/pre>\n\u8fd9\u4e2a\u5c31\u4e0d\u505a\u8fc7\u591a\u89e3\u91ca\u4e86\uff0c\u4e0d\u719f\u6089\u7684\u5c0f\u4f19\u4f34\u53ef\u4ee5\u7ffb\u770b\u524d\u9762\u7684\u6587\u7ae0\u3002<\/p>\n
\u4e0a\u9762\u8fd9\u4e09\u79cd\u65b9\u6848\u90fd\u662f\u4f20\u7edf\u65b9\u6848\u3002<\/p>\n
\u7279\u522b\u662f\u524d\u4e24\u79cd\uff0c\u5176\u5b9e\u6211\u4eec\u7528\u7684\u6bd4\u8f83\u5c11\uff0c\u524d\u4e24\u79cd\u6709\u4e00\u4e2a\u7f3a\u9677\uff0c\u5c31\u662f\u6211\u4eec\u914d\u7f6e\u7684\u7684 factory-method \u90fd\u662f\u901a\u8fc7\u53cd\u5c04\u6765\u8c03\u7528\u7684\uff0c\u901a\u8fc7\u53cd\u5c04\u8c03\u7528\u7684\u8bdd\uff0c\u591a\u591a\u5c11\u5c11\u6027\u80fd\u53d7\u70b9\u5f71\u54cd\u3002<\/p>\n
\u8fd9\u79cd factory-method \u5728 Spring \u4e2d\u5904\u7406\u7684\u6e90\u7801\u6267\u884c\u65f6\u5e8f\u56fe\u5982\u4e0b\uff1a<\/p>\n
![\"\"](\"https:\/\/segmentfault.com\/img\/remote\/1460000043994705\" "\\"\\"")
<\/p>\n
\u6240\u4ee5\u6700\u7ec8\u53cd\u5c04\u662f\u5728 SimpleInstantiationStrategy#instantiate<\/code> \u65b9\u6cd5\u4e2d\u6267\u884c\u7684\uff0c\u5c31\u662f\u5927\u5bb6\u975e\u5e38\u719f\u6089\u7684\u53cd\u5c04\u4ee3\u7801\u4e86\uff1a<\/p>\n@Override\npublic Object instantiate(RootBeanDefinition bd, @Nullable String beanName, BeanFactory owner,\n @Nullable Object factoryBean, final Method factoryMethod, Object... args) {\n ReflectionUtils.makeAccessible(factoryMethod);\n Method priorInvokedFactoryMethod = currentlyInvokedFactoryMethod.get();\n try {\n currentlyInvokedFactoryMethod.set(factoryMethod);\n Object result = factoryMethod.invoke(factoryBean, args);\n if (result == null) {\n result = new NullBean();\n }\n return result;\n }\n finally {\n if (priorInvokedFactoryMethod != null) {\n currentlyInvokedFactoryMethod.set(priorInvokedFactoryMethod);\n }\n else {\n currentlyInvokedFactoryMethod.remove();\n }\n }\n}<\/code><\/pre>\n\u597d\u4e86\uff0c\u8fd9\u662f\u4f20\u7edf\u7684\u89e3\u51b3\u65b9\u6848\u3002<\/p>\n
2. Spring5 \u89e3\u51b3\u65b9\u6848<\/h2>\n
Spring5 \u4e2d\u5f00\u59cb\u63d0\u4f9b\u4e86 Supplier\uff0c\u53ef\u4ee5\u901a\u8fc7\u63a5\u53e3\u56de\u8c03\u83b7\u53d6\u5230\u4e00\u4e2a Bean \u7684\u5b9e\u4f8b\uff0c\u8fd9\u79cd\u65b9\u5f0f\u663e\u7136\u6027\u80fd\u66f4\u597d\u4e00\u4e9b\u3002<\/p>\n
\u5982\u4e0b\uff1a<\/p>\n
AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();\nGenericBeanDefinition definition = new GenericBeanDefinition();\ndefinition.setBeanClass(Book.class);\ndefinition.setInstanceSupplier((Supplier<Book>) () -> {\n Book book = new Book();\n book.setName("\u6df1\u5165\u6d45\u51fa Spring Security");\n book.setAuthor("\u6c5f\u5357\u4e00\u70b9\u96e8");\n return book;\n});\nctx.registerBeanDefinition("b1", definition);\nctx.refresh();\nBook b = ctx.getBean("b1", Book.class);\nSystem.out.println("b = " + b);<\/code><\/pre>\n\u5173\u952e\u5c31\u662f\u901a\u8fc7\u8c03\u7528 BeanDefinition \u7684 setInstanceSupplier \u65b9\u6cd5\u53bb\u8bbe\u7f6e\u56de\u8c03\u3002\u5f53\u7136\uff0c\u4e0a\u9762\u8fd9\u6bb5\u4ee3\u7801\u8fd8\u53ef\u4ee5\u901a\u8fc7 Lambda \u8fdb\u4e00\u6b65\u7b80\u5316\uff1a<\/p>\n
public class BookSupplier {\n public Book getBook() {\n Book book = new Book();\n book.setName("\u6df1\u5165\u6d45\u51fa Spring Security");\n book.setAuthor("\u6c5f\u5357\u4e00\u70b9\u96e8");\n return book;\n }\n}<\/code><\/pre>\n\u7136\u540e\u8c03\u7528\u8fd9\u4e2a\u65b9\u6cd5\u5373\u53ef\uff1a<\/p>\n
AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();\nGenericBeanDefinition definition = new GenericBeanDefinition();\ndefinition.setBeanClass(Book.class);\nBookSupplier bookSupplier = new BookSupplier();\ndefinition.setInstanceSupplier(bookSupplier::getBook);\nctx.registerBeanDefinition("b1", definition);\nctx.refresh();\nBook b = ctx.getBean("b1", Book.class);\nSystem.out.println("b = " + b);<\/code><\/pre>\n\u8fd9\u662f\u4e0d\u662f\u66f4\u6709\u4e00\u70b9 Lambda \u7684\u611f\u89c9\u4e86\uff5e<\/p>\n
\u5728 Spring \u6e90\u7801\u4e2d\uff0c\u5904\u7406\u83b7\u53d6 Bean \u5b9e\u4f8b\u7684\u65f6\u5019\uff0c\u6709\u5982\u4e0b\u4e00\u4e2a\u5206\u652f\uff0c\u5c31\u662f\u5904\u7406 Supplier \u8fd9\u79cd\u60c5\u51b5\u7684\uff1a<\/p>\n
AbstractAutowireCapableBeanFactory#createBeanInstance<\/p>\n
protected BeanWrapper createBeanInstance(String beanName, RootBeanDefinition mbd, @Nullable Object[] args) {\n \/\/ Make sure bean class is actually resolved at this point.\n Class<?> beanClass = resolveBeanClass(mbd, beanName);\n if (beanClass != null && !Modifier.isPublic(beanClass.getModifiers()) && !mbd.isNonPublicAccessAllowed()) {\n throw new BeanCreationException(mbd.getResourceDescription(), beanName,\n "Bean class isn't public, and non-public access not allowed: " + beanClass.getName());\n }\n Supplier<?> instanceSupplier = mbd.getInstanceSupplier();\n if (instanceSupplier != null) {\n return obtainFromSupplier(instanceSupplier, beanName);\n }\n if (mbd.getFactoryMethodName() != null) {\n return instantiateUsingFactoryMethod(beanName, mbd, args);\n }\n \/\/...\n return instantiateBean(beanName, mbd);\n}\n\n@Nullable\nprivate Object obtainInstanceFromSupplier(Supplier<?> supplier, String beanName) {\n String outerBean = this.currentlyCreatedBean.get();\n this.currentlyCreatedBean.set(beanName);\n try {\n if (supplier instanceof InstanceSupplier<?> instanceSupplier) {\n return instanceSupplier.get(RegisteredBean.of((ConfigurableListableBeanFactory) this, beanName));\n }\n if (supplier instanceof ThrowingSupplier<?> throwableSupplier) {\n return throwableSupplier.getWithException();\n }\n return supplier.get();\n }\n}<\/code><\/pre>\n\u4e0a\u9762 obtainFromSupplier \u8fd9\u4e2a\u65b9\u6cd5\uff0c\u6700\u7ec8\u4f1a\u8c03\u7528\u5230\u7b2c\u4e8c\u4e2a\u65b9\u6cd5\u3002\u7b2c\u4e8c\u4e2a\u65b9\u6cd5\u4e2d\u7684 supplier.get();<\/code> \u5176\u5b9e\u6700\u7ec8\u5c31\u8c03\u7528\u5230\u6211\u4eec\u81ea\u5df1\u5199\u7684 getBook \u65b9\u6cd5\u4e86\u3002<\/p>\n\u597d\u5566\uff0c\u8fd9\u662f\u4ece Spring5 \u5f00\u59cb\u7ed3\u5408 Lamdba \u7684\u4e00\u79cd Bean \u6ce8\u5165\u65b9\u5f0f\uff0c\u611f\u5174\u8da3\u7684\u5c0f\u4f19\u4f34\u53ef\u4ee5\u8bd5\u8bd5\u54e6\uff5e<\/p>\n