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ControllerBeanNameHandlerMapping类详解 - HandlerMapping系列五

ControllerBeanNameHandlerMapping是AbstractControllerUrlHandlerMapping的实现类，通过声明在Web应用程序环境中的控制器类型来注册处理器映射的。它从控制器的Bean名字转换出控制器所服务的URL Pattern。这个转换规则是，把Bean名字加上前缀和后缀构成URL Pattern，然后，使用得到的Pattern匹配请求的URL，如果匹配成功，则使用匹配的Bean作为处理器返回。

buildUrlsForHandler() beanName及其别名作为url

@Override  
protected String[] buildUrlsForHandler(String beanName, Class beanClass) {  
	Listurls = new ArrayList();  
	urls.add(generatePathMapping(beanName));  
	String[] aliases = getApplicationContext().getAliases(beanName);  
	for (String alias : aliases) {  
		urls.add(generatePathMapping(alias));  
	}  
	return StringUtils.toStringArray(urls);  
}

generatePathMapping() beanName加上以下前缀等

protected String generatePathMapping(String beanName) {  
	String name = (beanName.startsWith("/") ? beanName : "/" + beanName);  
	StringBuilder path = new StringBuilder();  
	if (!name.startsWith(this.urlPrefix)) {  
		path.append(this.urlPrefix);  
	}  
	path.append(name);  
	if (!name.endsWith(this.urlSuffix)) {  
		path.append(this.urlSuffix);  
	}  
	return path.toString();  
}

ControllerBeanNameHandlerMapping源码

public class ControllerBeanNameHandlerMapping extends AbstractControllerUrlHandlerMapping {  
    private String urlPrefix = "";  
    private String urlSuffix = "";  
  
    @Override  
    protected String[] buildUrlsForHandler(String beanName, Class beanClass) {  
        Listurls = new ArrayList();  
          
        // 根据Bean名产生URL Pattern  
        urls.add(generatePathMaping(beanName));  
          
        // 对于Bean名的别名，以同样的规则产生URL Pattern  
        String[] aliases = getApplicationContext().getAliases(beanName);  
        for (String alias : aliases) {  
            urls.add(generatePathMapping(alias));  
        }  
          
        // 返回URL Pattern数组  
        return StringUtils.toStringArray(urls);  
    }  
    /** 
     * Prepends a '/' if required and appends the URL suffix to the name. 
     */  
    protected String generatePathMapping(String beanName) {  
        // 如果bean名不是以斜线(/)开头，则增加斜线(/)  
        String name = (beanName.startsWith("/") ? beanName : "/" + beanName);  
        StringBuilder path = new StringBuilder();  
          
        // 添加前缀  
        if (!name.startsWith(this.urlPrefix)) {  
            path.append(this.urlPrefix);  
        }  
          
        path.append(name);  
          
        // 添加后缀  
        if (!name.endsWith(this.urlSuffix)) {  
            path.append(this.urlSuffix);  
        }  
        return path.toString();  
    }  
}

ControllerBeanNameHandlerMapping实现的功能很简单，就是将beanName及其别名作为url返回。