# MappingRegistry
- Author: [HuiFer](https://github.com/huifer)
- 源码阅读仓库: [SourceHot-spring](https://github.com/SourceHot/spring-framework-read)
- 源码路径: `org.springframework.jms.annotation.EnableJms`
- 类全路径
- `org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.MappingRegistry`
- 基本属性
```java
class MappingRegistry {
/**
* key:mapping
* value: mapping registration
*/
private final Map<T, MappingRegistration<T>> registry = new HashMap<>();
/**
* key: mapping
* value: handlerMethod
*/
private final Map<T, HandlerMethod> mappingLookup = new LinkedHashMap<>();
/**
* key: url
* value: list mapping
*/
private final MultiValueMap<String, T> urlLookup = new LinkedMultiValueMap<>();
/**
* key: name
* value: handler method
*/
private final Map<String, List<HandlerMethod>> nameLookup = new ConcurrentHashMap<>();
/**
* key:handler method
* value: 跨域配置
*/
private final Map<HandlerMethod, CorsConfiguration> corsLookup = new ConcurrentHashMap<>();
/**
* 读写锁
*/
private final ReentrantReadWriteLock readWriteLock = new ReentrantReadWriteLock();
}
```
- 写一个简单的 controller 来进行解析
```java
@RestController
@RequestMapping("/demo")
public class DemoController {
@GetMapping("/do")
public Object go() {
return "fff";
}
}
```
- 前置链路追踪
- `org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping#registerHandlerMethod`
```java
protected void registerHandlerMethod(Object handler, Method method, RequestMappingInfo mapping) {
super.registerHandlerMethod(handler, method, mapping);
this.updateConsumesCondition(mapping, method);
}
```
- `org.springframework.web.servlet.handler.AbstractHandlerMethodMapping#registerHandlerMethod`
```JAVA
protected void registerHandlerMethod(Object handler, Method method, T mapping) {
this.mappingRegistry.register(mapping, handler, method);
}
```
- `org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.MappingRegistry#register`
本文重点的方法
先将对象截图出来方便后续理解
## createHandlerMethod
- `org.springframework.web.servlet.handler.AbstractHandlerMethodMapping#createHandlerMethod`
```java
protected HandlerMethod createHandlerMethod(Object handler, Method method) {
// 是否是字符串
if (handler instanceof String) {
// 创建对象
return new HandlerMethod((String) handler,
obtainApplicationContext().getAutowireCapableBeanFactory(), method);
}
return new HandlerMethod(handler, method);
}
```
- HandlerMethod 构造函数
```java
public HandlerMethod(String beanName, BeanFactory beanFactory, Method method){}
public HandlerMethod(Object bean, Method method) {}
```
## HandlerMethod
- 成员变量
```java
public class HandlerMethod {
/** Logger that is available to subclasses. */
protected final Log logger = LogFactory.getLog(getClass());
/**
* beanName 或者 bean 实例
*/
private final Object bean;
/**
* 上下文
*/
@Nullable
private final BeanFactory beanFactory;
/**
* bean 类型
*/
private final Class<?> beanType;
/**
* 处理方法
*/
private final Method method;
private final Method bridgedMethod;
/**
* 方法参数
*/
private final MethodParameter[] parameters;
}
```
## validateMethodMapping
- `org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.MappingRegistry#validateMethodMapping`
HandlerMethod 进行验证
```java
private void validateMethodMapping(HandlerMethod handlerMethod, T mapping) {
// Assert that the supplied mapping is unique.
// 从缓存中获取
HandlerMethod existingHandlerMethod = this.mappingLookup.get(mapping);
// 是否为空 , 是否相同
if (existingHandlerMethod != null && !existingHandlerMethod.equals(handlerMethod)) {
throw new IllegalStateException(
"Ambiguous mapping. Cannot map '" + handlerMethod.getBean() + "' method \n" +
handlerMethod + "\nto " + mapping + ": There is already '" +
existingHandlerMethod.getBean() + "' bean method\n" + existingHandlerMethod + " mapped.");
}
}
```
## getDirectUrls
- 找到 mapping 匹配的 url
- `org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.MappingRegistry#getDirectUrls`
```java
private List<String> getDirectUrls(T mapping) {
List<String> urls = new ArrayList<>(1);
// mapping.getPatternsCondition().getPatterns()
for (String path : getMappingPathPatterns(mapping)) {
// 是否匹配
if (!getPathMatcher().isPattern(path)) {
urls.add(path);
}
}
return urls;
}
```
## handlerMethod 和 name 绑定
```java
String name = null;
if (getNamingStrategy() != null) {
// 获取名字
// 类名#方法名
name = getNamingStrategy().getName(handlerMethod, mapping);
// 设置 handlerMethod + name 的关系
addMappingName(name, handlerMethod);
}
```
- `org.springframework.web.servlet.mvc.method.RequestMappingInfoHandlerMethodMappingNamingStrategy#getName`
```java
@Override
public String getName(HandlerMethod handlerMethod, RequestMappingInfo mapping) {
if (mapping.getName() != null) {
return mapping.getName();
}
StringBuilder sb = new StringBuilder();
// 短类名
String simpleTypeName = handlerMethod.getBeanType().getSimpleName();
for (int i = 0; i < simpleTypeName.length(); i++) {
if (Character.isUpperCase(simpleTypeName.charAt(i))) {
sb.append(simpleTypeName.charAt(i));
}
}
// 组装名称
// 类名+#+方法名称
sb.append(SEPARATOR).append(handlerMethod.getMethod().getName());
return sb.toString();
}
```
## initCorsConfiguration
- `org.springframework.web.servlet.handler.AbstractHandlerMethodMapping#initCorsConfiguration`
```java
@Override
protected CorsConfiguration initCorsConfiguration(Object handler, Method method, RequestMappingInfo mappingInfo) {
// 创建 handlerMethod
HandlerMethod handlerMethod = createHandlerMethod(handler, method);
// 获取 beanType
Class<?> beanType = handlerMethod.getBeanType();
// 获取跨域注解 CrossOrigin
CrossOrigin typeAnnotation = AnnotatedElementUtils.findMergedAnnotation(beanType, CrossOrigin.class);
CrossOrigin methodAnnotation = AnnotatedElementUtils.findMergedAnnotation(method, CrossOrigin.class);
if (typeAnnotation == null && methodAnnotation == null) {
return null;
}
// 跨域信息配置
CorsConfiguration config = new CorsConfiguration();
// 更新跨域配置
updateCorsConfig(config, typeAnnotation);
updateCorsConfig(config, methodAnnotation);
if (CollectionUtils.isEmpty(config.getAllowedMethods())) {
// 跨域配置赋给方法
for (RequestMethod allowedMethod : mappingInfo.getMethodsCondition().getMethods()) {
config.addAllowedMethod(allowedMethod.name());
}
}
// 应用跨域
return config.applyPermitDefaultValues();
}
```
## unregister
- `org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.MappingRegistry#unregister`
移除 mapping 信息
- 执行 map ， list 相关的移除方法.
```java
public void unregister(T mapping) {
this.readWriteLock.writeLock().lock();
try {
MappingRegistration<T> definition = this.registry.remove(mapping);
if (definition == null) {
return;
}
this.mappingLookup.remove(definition.getMapping());
for (String url : definition.getDirectUrls()) {
List<T> list = this.urlLookup.get(url);
if (list != null) {
list.remove(definition.getMapping());
if (list.isEmpty()) {
this.urlLookup.remove(url);
}
}
}
removeMappingName(definition);
this.corsLookup.remove(definition.getHandlerMethod());
}
finally {
this.readWriteLock.writeLock().unlock();
}
}
```