这篇文章主要给大家介绍了Spring IOC基于注解启动的相关资料，文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值，需要的朋友们下面来一起学习学习吧spring 基于注解启动 annotationconfigapplicationcontext annotationconfigwebapplicationcontext
annotationconfigapplicationcontext.png
<dependency>
<groupid>org.springframework</groupid>
<artifactid>spring-context</artifactid>
<version>${spring.version}</version>
</dependency>public static void main(string[] args) {
annotationconfigapplicationcontext applicationcontext = new annotationconfigapplicationcontext();
applicationcontext.register(beanconfig.class);
applicationcontext.refresh();
date date = applicationcontext.getbean("date",date.class);
system.out.println(date);
}annotationconfigapplicationcontext 构造函数 public annotationconfigapplicationcontext() {
//负责注册class ，读取器
this.reader = new annotatedbeandefinitionreader(this);
//负责扫描指定类路径下的class，注册bean
this.scanner = new classpathbeandefinitionscanner(this);
}annotatedbeandefinitionreader 构造方法 public annotatedbeandefinitionreader(beandefinitionregistry registry) {
this(registry, getorcreateenvironment(registry));
}
public annotatedbeandefinitionreader(beandefinitionregistry registry, environment environment) {
assert.notnull(registry, "beandefinitionregistry must not be null");
assert.notnull(environment, "environment must not be null");
this.registry = registry;
//初始化conditionevaluator
this.conditionevaluator = new conditionevaluator(registry, environment, null);
/** 在給定的注册表中註冊所有相关的post processors
* 判断容器是否已经存在给定注册表的bean，如果没有注册bean，并将bean放入容器中
* 把所有的处理处理器列出来
* configurationclasspostprocessor 內部管理的配置注解处理器
* autowiredannotationbeanpostprocessor 内部管理@autowired 的处理器
* requiredannotationbeanpostprocessor @required的处理器
* commonannotationbeanpostprocessor jsr-250注解处理器 ，先判断是否支持jsr，如果支持注册
* persistenceannotationbeanpostprocessor jpa管理 先使用类加载器查找是否存在，如果有这个包则注册
* eventlistenermethodprocessor @eventlistener的处理器
* defaulteventlistenerfactory 管理eventlistenerfactory处理器
*/
annotationconfigutils.registerannotationconfigprocessors(this.registry);
}public conditionevaluator(@nullable beandefinitionregistry registry,
@nullable environment environment, @nullable resourceloader resourceloader) {
this.context = new conditioncontextimpl(registry, environment, resourceloader);
}
//conditioncontextimpl 实现了conditioncontext接口，conditionevaluator静态内部类
public conditioncontextimpl(@nullable beandefinitionregistry registry,
@nullable environment environment, @nullable resourceloader resourceloader) {
this.registry = registry;
this.beanfactory = deducebeanfactory(registry);
this.environment = (environment != null ? environment : deduceenvironment(registry));
this.resourceloader = (resourceloader != null ? resourceloader : deduceresourceloader(registry));
this.classloader = deduceclassloader(resourceloader, this.beanfactory);
}classpathbeandefinitionscanner构造函数 public classpathbeandefinitionscanner(beandefinitionregistry registry) {
this(registry, true);
}
public classpathbeandefinitionscanner(beandefinitionregistry registry, boolean usedefaultfilters) {
this(registry, usedefaultfilters, getorcreateenvironment(registry));
}
public classpathbeandefinitionscanner(beandefinitionregistry registry, boolean usedefaultfilters,
environment environment) {
this(registry, usedefaultfilters, environment,
(registry instanceof resourceloader ? (resourceloader) registry : null));
}
public classpathbeandefinitionscanner(beandefinitionregistry registry, boolean usedefaultfilters,
environment environment, @nullable resourceloader resourceloader) {
assert.notnull(registry, "beandefinitionregistry must not be null");
this.registry = registry;
if (usedefaultfilters) {
registerdefaultfilters();
}
setenvironment(environment);
setresourceloader(resourceloader);
}
protected void registerdefaultfilters() {
this.includefilters.add(new annotationtypefilter(component.class));
classloader cl = classpathscanningcandidatecomponentprovider.class.getclassloader();
try {
this.includefilters.add(new annotationtypefilter(
((class<? extends annotation>) classutils.forname("javax.annotation.managedbean", cl)), false));
logger.debug("jsr-250 'javax.annotation.managedbean' found and supported for component scanning");
}
catch (classnotfoundexception ex) {
}
try {
this.includefilters.add(new annotationtypefilter(
((class<? extends annotation>) classutils.forname("javax.inject.named", cl)), false));
logger.debug("jsr-330 'javax.inject.named' annotation found and supported for component scanning");
}
catch (classnotfoundexception ex) {
// jsr-330 api not available - simply skip.
}
}applicationcontext.register(beanconfig.class) public void register(class<?>... annotatedclasses) {
assert.notempty(annotatedclasses, "at least one annotated class must be specified");
this.reader.register(annotatedclasses); //调用 刚刚初始化读取器
}
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============================annotatedbeandefinitionreader 读取器代码======================================================================================================
public void register(class<?>... annotatedclasses) {
for (class<?> annotatedclass : annotatedclasses) {
registerbean(annotatedclass);
}
}
public void registerbean(class<?> annotatedclass) {
doregisterbean(annotatedclass, null, null, null);
}
/**
*从给定的bean解析class给定的注解，执行相应的初始化，保存到spring容器中
*/
<t> void doregisterbean(class<t> annotatedclass, @nullable supplier<t> instancesupplier, @nullable string name,
@nullable class<? extends annotation>[] qualifiers, beandefinitioncustomizer... definitioncustomizers) {
//根据class的annotated 得出元数据 annotationmetadata
annotatedgenericbeandefinition abd = new annotatedgenericbeandefinition(annotatedclass);
/**
* 判断注册的class 是否包含@conditional注解，如果有获取全部value，放入list中
* 排序后，遍历所有的conditiion的实现，使用反射获取对象，执行matches方法，
* 如果发现有返回false，中断循环直接返回true，
*/
if (this.conditionevaluator.shouldskip(abd.getmetadata())) { //如果 @conditional条件不满足，不进行注册
return;
}
abd.setinstancesupplier(instancesupplier);
//解析class是否有@scope,解析@scope注解返回scopemetadata对象，没有直接返回空
scopemetadata scopemetadata = this.scopemetadataresolver.resolvescopemetadata(abd);
abd.setscope(scopemetadata.getscopename());
//判断注解上value是否有值，有就使用这个作为beanname，没有则取类名
string beanname = (name != null ? name : this.beannamegenerator.generatebeanname(abd, this.registry));
//继续解析annotationmetadata的@lazy,@primary，@dependson，@role，@description的注解，放入结果放入对象的属性中
annotationconfigutils.processcommondefinitionannotations(abd);
//这个类只是beandefinition 包装类
beandefinitionholder definitionholder = new beandefinitionholder(abd, beanname);
//是否需要代理类，如果是则修改内部属性，重新生成beandefinition 对象
definitionholder = annotationconfigutils.applyscopedproxymode(scopemetadata, definitionholder, this.registry);
//调用defaultlistablebeanfactory.registerbeandefinition的方法，做一些安全性校验再，将definitionholder 放入register容器中
beandefinitionreaderutils.registerbeandefinition(definitionholder, this.registry);
}public void registerbeandefinition(string beanname, beandefinition beandefinition)
throws beandefinitionstoreexception {
assert.hastext(beanname, "bean name must not be empty");
assert.notnull(beandefinition, "beandefinition must not be null");
if (beandefinition instanceof abstractbeandefinition) {
try {
//对beandefinition 进行校验判断methodoverrides不能为空，必须拥有工厂方法
((abstractbeandefinition) beandefinition).validate();
}
catch (beandefinitionvalidationexception ex) {
throw new beandefinitionstoreexception(beandefinition.getresourcedescription(), beanname,
"validation of bean definition failed", ex);
}
}
beandefinition oldbeandefinition;
oldbeandefinition = this.beandefinitionmap.get(beanname);
if (oldbeandefinition != null) {
//这个方法是判断是否允许出现重名bean，并且是不同的定义bean，是否可以覆盖前者
if (!isallowbeandefinitionoverriding()) {
throw new beandefinitionstoreexception(beandefinition.getresourcedescription(), beanname,
"cannot register bean definition [" + beandefinition + "] for bean '" + beanname +
"': there is already [" + oldbeandefinition + "] bound.");
}
else if (oldbeandefinition.getrole() < beandefinition.getrole()) {
// e.g. was role_application, now overriding with role_support or role_infrastructure
if (this.logger.iswarnenabled()) {
this.logger.warn("overriding user-defined bean definition for bean '" + beanname +
"' with a framework-generated bean definition: replacing [" +
oldbeandefinition + "] with [" + beandefinition + "]");
}
}
else if (!beandefinition.equals(oldbeandefinition)) {
if (this.logger.isinfoenabled()) {
this.logger.info("overriding bean definition for bean '" + beanname +
"' with a different definition: replacing [" + oldbeandefinition +
"] with [" + beandefinition + "]");
}
}
else {
if (this.logger.isdebugenabled()) {
this.logger.debug("overriding bean definition for bean '" + beanname +
"' with an equivalent definition: replacing [" + oldbeandefinition +
"] with [" + beandefinition + "]");
}
}
this.beandefinitionmap.put(beanname, beandefinition);
}
else {
//调用alreadycreated.isempty()，alreadycreated set对象，保存已经创建beanname
//文档中表示created，跟这里注册应该不是同一个行为，这个要看到后面才知道什么意思
if (hasbeancreationstarted()) {
synchronized (this.beandefinitionmap) {//更新数据
this.beandefinitionmap.put(beanname, beandefinition);
list<string> updateddefinitions = new arraylist<>(this.beandefinitionnames.size() + 1);
updateddefinitions.addall(this.beandefinitionnames);
updateddefinitions.add(beanname);
this.beandefinitionnames = updateddefinitions;
if (this.manualsingletonnames.contains(beanname)) {
set<string> updatedsingletons = new linkedhashset<>(this.manualsingletonnames);
updatedsingletons.remove(beanname);
this.manualsingletonnames = updatedsingletons;
}
}
}
else {
//spring beandefinition 容器，一个map转载
this.beandefinitionmap.put(beanname, beandefinition);
//保存beanname，主要用于记录每个bean注册顺序
this.beandefinitionnames.add(beanname);
//删除单例，注册成一个普通bean
this.manualsingletonnames.remove(beanname);
}
this.frozenbeandefinitionnames = null;
}
if (oldbeandefinition != null || containssingleton(beanname)) {
//更新spring容器里beanname
resetbeandefinition(beanname);
}
}beandefinition rootbeandefinition spring factory中的特定bean annotatedgenericbeandefinition 用户自定义bean 总结 CodeAE代码之家 的支持。 
编程语言
发布于：2021-09-18 15:46
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