spring ServletContextAttributeFactoryBean 源码
spring ServletContextAttributeFactoryBean 代码
文件路径：/spring-web/src/main/java/org/springframework/web/context/support/ServletContextAttributeFactoryBean.java
/*
* Copyright 2002-2017 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.web.context.support;
import jakarta.servlet.ServletContext;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.lang.Nullable;
import org.springframework.web.context.ServletContextAware;
/**
* {@link FactoryBean} that fetches a specific, existing ServletContext attribute.
* Exposes that ServletContext attribute when used as bean reference,
* effectively making it available as named Spring bean instance.
*
* <p>Intended to link in ServletContext attributes that exist before
* the startup of the Spring application context. Typically, such
* attributes will have been put there by third-party web frameworks.
* In a purely Spring-based web application, no such linking in of
* ServletContext attributes will be necessary.
*
* <p><b>NOTE:</b> As of Spring 3.0, you may also use the "contextAttributes" default
* bean which is of type Map, and dereference it using an "#{contextAttributes.myKey}"
* expression to access a specific attribute by name.
*
* @author Juergen Hoeller
* @since 1.1.4
* @see org.springframework.web.context.WebApplicationContext#CONTEXT_ATTRIBUTES_BEAN_NAME
* @see ServletContextParameterFactoryBean
*/
public class ServletContextAttributeFactoryBean implements FactoryBean<Object>, ServletContextAware {
@Nullable
private String attributeName;
@Nullable
private Object attribute;
/**
* Set the name of the ServletContext attribute to expose.
*/
public void setAttributeName(String attributeName) {
this.attributeName = attributeName;
}
@Override
public void setServletContext(ServletContext servletContext) {
if (this.attributeName == null) {
throw new IllegalArgumentException("Property 'attributeName' is required");
}
this.attribute = servletContext.getAttribute(this.attributeName);
if (this.attribute == null) {
throw new IllegalStateException("No ServletContext attribute '" + this.attributeName + "' found");
}
}
@Override
@Nullable
public Object getObject() throws Exception {
return this.attribute;
}
@Override
public Class<?> getObjectType() {
return (this.attribute != null ? this.attribute.getClass() : null);
}
@Override
public boolean isSingleton() {
return true;
}
}
相关信息
相关文章
spring AbstractRefreshableWebApplicationContext 源码
spring AnnotationConfigWebApplicationContext 源码
spring ContextExposingHttpServletRequest 源码
spring GenericWebApplicationContext 源码
spring GroovyWebApplicationContext 源码
spring HttpRequestHandlerServlet 源码
spring ServletConfigPropertySource 源码
0
赞
热门推荐
-
2、 - 优质文章
-
3、 gate.io
-
8、 golang
-
9、 openharmony
-
10、 Vue中input框自动聚焦