【发布时间】：2011-07-11 01:30:58
【问题描述】：
我想测试部署在 tomcat 上的 REST 服务。为了使用 JUnit 做到这一点，我嵌入了运行良好的 Tomcat 6。
现在，我需要访问 Spring 上下文，因为我需要访问 DAO 和其他 bean。
有没有人知道如何实现这一点？我尝试使用 RootContext，但找不到任何东西。
真诚地， 埃里克
编辑：我知道已经找到了解决方案，但这是一个糟糕的 hack：
import java.io.IOException;
import java.util.Enumeration;
import java.util.Map;
import java.util.Properties;
import java.util.concurrent.ConcurrentHashMap;
import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.access.BeanFactoryLocator;
import org.springframework.beans.factory.access.BeanFactoryReference;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextException;
import org.springframework.context.access.ContextSingletonBeanFactoryLocator;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.support.PropertiesLoaderUtils;
import org.springframework.util.ClassUtils;
import org.springframework.util.ObjectUtils;
import org.springframework.web.context.ConfigurableWebApplicationContext;
import org.springframework.web.context.ContextLoader;
import org.springframework.web.context.WebApplicationContext;
public class ContextLoaderListener extends ContextLoader implements ServletContextListener {
private ContextLoader contextLoader;
/**
* Config param for the root WebApplicationContext implementation class to
* use: "<code>contextClass</code>"
*/
public static final String CONTEXT_CLASS_PARAM = "contextClass";
/**
* Name of servlet context parameter (i.e., "<code>contextConfigLocation</code>")
* that can specify the config location for the root context, falling back
* to the implementation's default otherwise.
* @see org.springframework.web.context.support.XmlWebApplicationContext#DEFAULT_CONFIG_LOCATION
*/
public static final String CONFIG_LOCATION_PARAM = "contextConfigLocation";
/**
* Optional servlet context parameter (i.e., "<code>locatorFactorySelector</code>")
* used only when obtaining a parent context using the default implementation
* of {@link #loadParentContext(ServletContext servletContext)}.
* Specifies the 'selector' used in the
* {@link ContextSingletonBeanFactoryLocator#getInstance(String selector)}
* method call, which is used to obtain the BeanFactoryLocator instance from
* which the parent context is obtained.
* <p>The default is <code>classpath*:beanRefContext.xml</code>,
* matching the default applied for the
* {@link ContextSingletonBeanFactoryLocator#getInstance()} method.
* Supplying the "parentContextKey" parameter is sufficient in this case.
*/
public static final String LOCATOR_FACTORY_SELECTOR_PARAM = "locatorFactorySelector";
/**
* Optional servlet context parameter (i.e., "<code>parentContextKey</code>")
* used only when obtaining a parent context using the default implementation
* of {@link #loadParentContext(ServletContext servletContext)}.
* Specifies the 'factoryKey' used in the
* {@link BeanFactoryLocator#useBeanFactory(String factoryKey)} method call,
* obtaining the parent application context from the BeanFactoryLocator instance.
* <p>Supplying this "parentContextKey" parameter is sufficient when relying
* on the default <code>classpath*:beanRefContext.xml</code> selector for
* candidate factory references.
*/
public static final String LOCATOR_FACTORY_KEY_PARAM = "parentContextKey";
/**
* Name of the class path resource (relative to the ContextLoader class)
* that defines ContextLoader's default strategy names.
*/
private static final String DEFAULT_STRATEGIES_PATH = "ContextLoader.properties";
private static final Properties defaultStrategies;
static {
// Load default strategy implementations from properties file.
// This is currently strictly internal and not meant to be customized
// by application developers.
try {
ClassPathResource resource = new ClassPathResource(DEFAULT_STRATEGIES_PATH, ContextLoader.class);
defaultStrategies = PropertiesLoaderUtils.loadProperties(resource);
}
catch (IOException ex) {
throw new IllegalStateException("Could not load 'ContextLoader.properties': " + ex.getMessage());
}
}
/**
* Map from (thread context) ClassLoader to corresponding 'current' WebApplicationContext.
*/
private static final Map<ClassLoader, WebApplicationContext> currentContextPerThread =
new ConcurrentHashMap<ClassLoader, WebApplicationContext>(1);
/**
* The 'current' WebApplicationContext, if the ContextLoader class is
* deployed in the web app ClassLoader itself.
*/
private static volatile WebApplicationContext currentContext;
/**
* The root WebApplicationContext instance that this loader manages.
*/
private WebApplicationContext context;
/**
* Holds BeanFactoryReference when loading parent factory via
* ContextSingletonBeanFactoryLocator.
*/
private BeanFactoryReference parentContextRef;
/**
* Initialize Spring's web application context for the given servlet context,
* according to the "{@link #CONTEXT_CLASS_PARAM contextClass}" and
* "{@link #CONFIG_LOCATION_PARAM contextConfigLocation}" context-params.
* @param servletContext current servlet context
* @return the new WebApplicationContext
* @see #CONTEXT_CLASS_PARAM
* @see #CONFIG_LOCATION_PARAM
*/
public WebApplicationContext initWebApplicationContext(ServletContext servletContext) {
if (servletContext.getAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE) != null) {
throw new IllegalStateException(
"Cannot initialize context because there is already a root application context present - " +
"check whether you have multiple ContextLoader* definitions in your web.xml!");
}
Log logger = LogFactory.getLog(ContextLoader.class);
servletContext.log("Initializing Spring root WebApplicationContext");
if (logger.isInfoEnabled()) {
logger.info("Root WebApplicationContext: initialization started");
}
long startTime = System.currentTimeMillis();
try {
// Determine parent for root web application context, if any.
ApplicationContext parent = loadParentContext(servletContext);
// Store context in local instance variable, to guarantee that
// it is available on ServletContext shutdown.
this.context = createWebApplicationContext(servletContext, parent);
servletContext.setAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE, this.context);
ClassLoader ccl = Thread.currentThread().getContextClassLoader();
if (ccl == ContextLoader.class.getClassLoader()) {
currentContext = this.context;
}
else if (ccl != null) {
currentContextPerThread.put(ccl, this.context);
}
if (logger.isDebugEnabled()) {
logger.debug("Published root WebApplicationContext as ServletContext attribute with name [" +
WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE + "]");
}
if (logger.isInfoEnabled()) {
long elapsedTime = System.currentTimeMillis() - startTime;
logger.info("Root WebApplicationContext: initialization completed in " + elapsedTime + " ms");
}
return this.context;
}
catch (RuntimeException ex) {
logger.error("Context initialization failed", ex);
servletContext.setAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE, ex);
throw ex;
}
catch (Error err) {
logger.error("Context initialization failed", err);
servletContext.setAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE, err);
throw err;
}
}
/**
* Instantiate the root WebApplicationContext for this loader, either the
* default context class or a custom context class if specified.
* <p>This implementation expects custom contexts to implement the
* {@link ConfigurableWebApplicationContext} interface.
* Can be overridden in subclasses.
* <p>In addition, {@link #customizeContext} gets called prior to refreshing the
* context, allowing subclasses to perform custom modifications to the context.
* @param sc current servlet context
* @param parent the parent ApplicationContext to use, or <code>null</code> if none
* @return the root WebApplicationContext
* @see ConfigurableWebApplicationContext
*/
protected WebApplicationContext createWebApplicationContext(ServletContext sc, ApplicationContext parent) {
Class<?> contextClass = determineContextClass(sc);
if (!ConfigurableWebApplicationContext.class.isAssignableFrom(contextClass)) {
throw new ApplicationContextException("Custom context class [" + contextClass.getName() +
"] is not of type [" + ConfigurableWebApplicationContext.class.getName() + "]");
}
ConfigurableWebApplicationContext wac =
(ConfigurableWebApplicationContext) BeanUtils.instantiateClass(contextClass);
// Assign the best possible id value.
if (sc.getMajorVersion() == 2 && sc.getMinorVersion() < 5) {
// Servlet <= 2.4: resort to name specified in web.xml, if any.
String servletContextName = sc.getServletContextName();
wac.setId(ConfigurableWebApplicationContext.APPLICATION_CONTEXT_ID_PREFIX +
ObjectUtils.getDisplayString(servletContextName));
}
else {
// Servlet 2.5's getContextPath available!
try {
String contextPath = (String) ServletContext.class.getMethod("getContextPath").invoke(sc);
wac.setId(ConfigurableWebApplicationContext.APPLICATION_CONTEXT_ID_PREFIX +
ObjectUtils.getDisplayString(contextPath));
}
catch (Exception ex) {
throw new IllegalStateException("Failed to invoke Servlet 2.5 getContextPath method", ex);
}
}
wac.setParent(parent);
wac.setServletContext(sc);
wac.setConfigLocation(sc.getInitParameter(CONFIG_LOCATION_PARAM));
customizeContext(sc, wac);
wac.refresh();
return wac;
}
/**
* Return the WebApplicationContext implementation class to use, either the
* default XmlWebApplicationContext or a custom context class if specified.
* @param servletContext current servlet context
* @return the WebApplicationContext implementation class to use
* @see #CONTEXT_CLASS_PARAM
* @see org.springframework.web.context.support.XmlWebApplicationContext
*/
protected Class<?> determineContextClass(ServletContext servletContext) {
String contextClassName = servletContext.getInitParameter(CONTEXT_CLASS_PARAM);
if (contextClassName != null) {
try {
return ClassUtils.forName(contextClassName, ClassUtils.getDefaultClassLoader());
}
catch (ClassNotFoundException ex) {
throw new ApplicationContextException(
"Failed to load custom context class [" + contextClassName + "]", ex);
}
}
else {
contextClassName = defaultStrategies.getProperty(WebApplicationContext.class.getName());
try {
return ClassUtils.forName(contextClassName, ContextLoader.class.getClassLoader());
}
catch (ClassNotFoundException ex) {
throw new ApplicationContextException(
"Failed to load default context class [" + contextClassName + "]", ex);
}
}
}
/**
* Customize the {@link ConfigurableWebApplicationContext} created by this
* ContextLoader after config locations have been supplied to the context
* but before the context is <em>refreshed</em>.
* <p>The default implementation is empty but can be overridden in subclasses
* to customize the application context.
* @param servletContext the current servlet context
* @param applicationContext the newly created application context
* @see #createWebApplicationContext(ServletContext, ApplicationContext)
*/
protected void customizeContext(
ServletContext servletContext, ConfigurableWebApplicationContext applicationContext) {
}
/**
* Template method with default implementation (which may be overridden by a
* subclass), to load or obtain an ApplicationContext instance which will be
* used as the parent context of the root WebApplicationContext. If the
* return value from the method is null, no parent context is set.
* <p>The main reason to load a parent context here is to allow multiple root
* web application contexts to all be children of a shared EAR context, or
* alternately to also share the same parent context that is visible to
* EJBs. For pure web applications, there is usually no need to worry about
* having a parent context to the root web application context.
* <p>The default implementation uses
* {@link org.springframework.context.access.ContextSingletonBeanFactoryLocator},
* configured via {@link #LOCATOR_FACTORY_SELECTOR_PARAM} and
* {@link #LOCATOR_FACTORY_KEY_PARAM}, to load a parent context
* which will be shared by all other users of ContextsingletonBeanFactoryLocator
* which also use the same configuration parameters.
* @param servletContext current servlet context
* @return the parent application context, or <code>null</code> if none
* @see org.springframework.context.access.ContextSingletonBeanFactoryLocator
*/
protected ApplicationContext loadParentContext(ServletContext servletContext) {
ApplicationContext parentContext = null;
String locatorFactorySelector = servletContext.getInitParameter(LOCATOR_FACTORY_SELECTOR_PARAM);
String parentContextKey = servletContext.getInitParameter(LOCATOR_FACTORY_KEY_PARAM);
if (parentContextKey != null) {
// locatorFactorySelector may be null, indicating the default "classpath*:beanRefContext.xml"
BeanFactoryLocator locator = ContextSingletonBeanFactoryLocator.getInstance(locatorFactorySelector);
Log logger = LogFactory.getLog(ContextLoader.class);
if (logger.isDebugEnabled()) {
logger.debug("Getting parent context definition: using parent context key of '" +
parentContextKey + "' with BeanFactoryLocator");
}
this.parentContextRef = locator.useBeanFactory(parentContextKey);
parentContext = (ApplicationContext) this.parentContextRef.getFactory();
}
return parentContext;
}
/**
* Close Spring's web application context for the given servlet context. If
* the default {@link #loadParentContext(ServletContext)} implementation,
* which uses ContextSingletonBeanFactoryLocator, has loaded any shared
* parent context, release one reference to that shared parent context.
* <p>If overriding {@link #loadParentContext(ServletContext)}, you may have
* to override this method as well.
* @param servletContext the ServletContext that the WebApplicationContext runs in
*/
public void closeWebApplicationContext(ServletContext servletContext) {
servletContext.log("Closing Spring root WebApplicationContext");
try {
if (this.context instanceof ConfigurableWebApplicationContext) {
((ConfigurableWebApplicationContext) this.context).close();
}
}
finally {
ClassLoader ccl = Thread.currentThread().getContextClassLoader();
if (ccl == ContextLoader.class.getClassLoader()) {
currentContext = null;
}
else if (ccl != null) {
currentContextPerThread.remove(ccl);
}
servletContext.removeAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE);
if (this.parentContextRef != null) {
this.parentContextRef.release();
}
}
}
/**
* Obtain the Spring root web application context for the current thread
* (i.e. for the current thread's context ClassLoader, which needs to be
* the web application's ClassLoader).
* @return the current root web application context, or <code>null</code>
* if none found
* @see org.springframework.web.context.support.SpringBeanAutowiringSupport
*/
public static WebApplicationContext getCurrentWebApplicationContext() {
ClassLoader ccl = Thread.currentThread().getContextClassLoader();
if (ccl != null) {
WebApplicationContext ccpt = currentContextPerThread.get(ccl);
if (ccpt != null) {
return ccpt;
}
}
return currentContext;
}
/**
* Initialize the root web application context.
*/
public void contextInitialized(ServletContextEvent event) {
this.contextLoader = createContextLoader();
if (this.contextLoader == null) {
this.contextLoader = this;
}
this.contextLoader.initWebApplicationContext(event.getServletContext());
}
/**
* Create the ContextLoader to use. Can be overridden in subclasses.
* @return the new ContextLoader
* @deprecated in favor of simply subclassing ContextLoaderListener itself
* (which extends ContextLoader, as of Spring 3.0)
*/
@Deprecated
protected ContextLoader createContextLoader() {
return null;
}
/**
* Return the ContextLoader used by this listener.
* @return the current ContextLoader
* @deprecated in favor of simply subclassing ContextLoaderListener itself
* (which extends ContextLoader, as of Spring 3.0)
*/
@Deprecated
public ContextLoader getContextLoader() {
return this.contextLoader;
}
/**
* Close the root web application context.
*/
public void contextDestroyed(ServletContextEvent event) {
if (this.contextLoader != null) {
this.contextLoader.closeWebApplicationContext(event.getServletContext());
}
cleanupAttributes(event.getServletContext());
}
/**
* Find all ServletContext attributes which implement {@link DisposableBean}
* and destroy them, removing all affected ServletContext attributes eventually.
* @param sc the ServletContext to check
*/
static void cleanupAttributes(ServletContext sc) {
Enumeration attrNames = sc.getAttributeNames();
while (attrNames.hasMoreElements()) {
String attrName = (String) attrNames.nextElement();
if (attrName.startsWith("org.springframework.")) {
Object attrValue = sc.getAttribute(attrName);
if (attrValue instanceof DisposableBean) {
try {
((DisposableBean) attrValue).destroy();
}
catch (Throwable ex) {
System.out.println("Couldn't invoke destroy method of attribute with name '" + attrName + "'");
}
}
}
}
}
public WebApplicationContext getContext() {
return context;
}
}
现在，将 ContextLoaderListener 添加到 web.xml 而不是 spring ContextLoaderListener。自定义的 ContextLoaderListener 和 spring ContextLoaderListener 的行为完全一样，但是有另外一个方法 getContext()。
因此，如果您正在运行 Web 服务器，则可以通过以下方式访问 Spring 上下文：
上下文 rootContext = this.tomcat.getRootContext(); System.out.println("上下文");
ContextLoaderListener ctxListener = (ContextLoaderListener) rootContext.getApplicationLifecycleListeners()[0];
XmlWebApplicationContext ctx = (XmlWebApplicationContext)ctxListener .getContext();
【问题讨论】：