com.github.datalking.web.context.ContextLoader Maven / Gradle / Ivy
package com.github.datalking.web.context;
import com.github.datalking.context.ApplicationContext;
import com.github.datalking.context.ApplicationContextInitializer;
import com.github.datalking.context.ConfigurableApplicationContext;
import com.github.datalking.util.Assert;
import com.github.datalking.util.ClassUtils;
import com.github.datalking.util.ObjectUtils;
import com.github.datalking.util.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.servlet.ServletContext;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.concurrent.ConcurrentHashMap;
/**
* 实际执行root application context的初始化
*/
public class ContextLoader {
private static Logger logger = LoggerFactory.getLogger(ContextLoader.class);
public static final String CONTEXT_ID_PARAM = "contextId";
public static final String CONFIG_LOCATION_PARAM = "contextConfigLocation";
public static final String CONTEXT_CLASS_PARAM = "contextClass";
public static final String CONTEXT_INITIALIZER_CLASSES_PARAM = "contextInitializerClasses";
public static final String GLOBAL_INITIALIZER_CLASSES_PARAM = "globalInitializerClasses";
public static final String LOCATOR_FACTORY_SELECTOR_PARAM = "locatorFactorySelector";
public static final String LOCATOR_FACTORY_KEY_PARAM = "parentContextKey";
private static final String INIT_PARAM_DELIMITERS = ",; \t\n";
// 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());
// }
// }
private static final Map currentContextPerThread = new ConcurrentHashMap<>(1);
private static volatile WebApplicationContext currentContext;
// root
private WebApplicationContext context;
// private BeanFactoryReference parentContextRef;
public ContextLoader() {
}
public ContextLoader(WebApplicationContext context) {
this.context = context;
}
public WebApplicationContext initWebApplicationContext(ServletContext servletContext) {
if (servletContext.getAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE) != null) {
throw new IllegalStateException("Cannot initialize context because a root application context already exists.");
}
servletContext.log("Initializing Spring root WebApplicationContext");
if (logger.isInfoEnabled()) {
logger.info("Root WebApplicationContext: initialization started");
}
long startTime = System.currentTimeMillis();
try {
// Store context in local instance variable, to guarantee that it is available on ServletContext shutdown.
if (this.context == null) {
this.context = createWebApplicationContext(servletContext);
}
if (this.context instanceof ConfigurableWebApplicationContext) {
ConfigurableWebApplicationContext cwac = (ConfigurableWebApplicationContext) this.context;
if (!cwac.isActive()) {
// The context has not yet been refreshed -> provide services such as setting the parent context, setting the application context id, etc
if (cwac.getParent() == null) {
// The context instance was injected without an explicit parent -> determine parent for root web application context, if any.
// ApplicationContext parent = loadParentContext(servletContext);
// cwac.setParent(parent);
}
configureAndRefreshWebApplicationContext(cwac, servletContext);
}
}
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;
}
}
protected WebApplicationContext createWebApplicationContext(ServletContext sc) {
Class contextClass = determineContextClass(sc);
if (!ConfigurableWebApplicationContext.class.isAssignableFrom(contextClass)) {
try {
throw new Exception("Custom context class [" + contextClass.getName() + "] is not of type [" + ConfigurableWebApplicationContext.class.getName() + "]");
} catch (Exception e) {
e.printStackTrace();
}
}
//return (ConfigurableWebApplicationContext) BeanUtils.instantiateClass(contextClass);
Object obj = null;
try {
obj = contextClass.newInstance();
} catch (InstantiationException | IllegalAccessException e) {
e.printStackTrace();
}
return (ConfigurableWebApplicationContext) obj;
}
@Deprecated
protected WebApplicationContext createWebApplicationContext(ServletContext sc, ApplicationContext parent) {
return createWebApplicationContext(sc);
}
protected Class determineContextClass(ServletContext servletContext) {
String contextClassName = servletContext.getInitParameter(CONTEXT_CLASS_PARAM);
if (contextClassName != null) {
try {
return ClassUtils.forName(contextClassName, this.getClass().getClassLoader());
} catch (ClassNotFoundException ex) {
try {
throw new Exception("Failed to load custom context class [" + contextClassName + "]", ex);
} catch (Exception e) {
e.printStackTrace();
}
}
}
// 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);
// }
// }
return null;
}
protected void configureAndRefreshWebApplicationContext(ConfigurableWebApplicationContext wac, ServletContext sc) {
// if (ObjectUtils.identityToString(wac).equals(wac.getId())) {
// // The application context id is still set to its original default value -> assign a more useful id based on available information
// String idParam = sc.getInitParameter(CONTEXT_ID_PARAM);
//
// if (idParam != null) {
// wac.setId(idParam);
// } else {
// // Generate default id...
// if (sc.getMajorVersion() == 2 && sc.getMinorVersion() < 5) {
// // Servlet <= 2.4: resort to name specified in web.xml, if any.
// wac.setId(ConfigurableWebApplicationContext.APPLICATION_CONTEXT_ID_PREFIX +
// ObjectUtils.getDisplayString(sc.getServletContextName()));
// } else {
// wac.setId(ConfigurableWebApplicationContext.APPLICATION_CONTEXT_ID_PREFIX +
// ObjectUtils.getDisplayString(sc.getContextPath()));
// }
// }
// }
wac.setServletContext(sc);
// String configLocationParam = sc.getInitParameter(CONFIG_LOCATION_PARAM);
// if (configLocationParam != null) {
// wac.setConfigLocation(configLocationParam);
// }
// The wac environment's #initPropertySources will be called in any case when the context
// is refreshed; do it eagerly here to ensure servlet property sources are in place for
// use in any post-processing or initialization that occurs below prior to #refresh
// ConfigurableEnvironment env = wac.getEnvironment();
// if (env instanceof ConfigurableWebEnvironment) {
// ((ConfigurableWebEnvironment) env).initPropertySources(sc, null);
// }
//customizeContext(sc, wac);
wac.refresh();
}
// protected void customizeContext(ServletContext sc, ConfigurableWebApplicationContext wac) {
// List>> initializerClasses = determineContextInitializerClasses(sc);
// if (initializerClasses.isEmpty()) {
// return;
// }
//
// ArrayList> initializerInstances = new ArrayList>();
//
// for (Class> initializerClass : initializerClasses) {
// Class initializerContextClass = GenericTypeResolver.resolveTypeArgument(initializerClass, ApplicationContextInitializer.class);
// if (initializerContextClass != null) {
// Assert.isAssignable(initializerContextClass, wac.getClass(), String.format(
// "Could not add context initializer [%s] since its generic parameter [%s] " +
// "is not assignable from the type of application context used by this " +
// "context loader [%s]: ", initializerClass.getName(), initializerContextClass.getName(),
// wac.getClass().getName()));
// }
//
// Object obj=initializerClass.newInstance();
// initializerInstances.add(obj);
// }
//
// // AnnotationAwareOrderComparator.sort(initializerInstances);
// for (ApplicationContextInitializer initializer : initializerInstances) {
// initializer.initialize(wac);
// }
// }
/**
* Return the WebApplicationContext implementation class to use, either the
* default XmlWebApplicationContext or a custom context class if specified.
*/
// 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);
// }
// }
// }
protected List>> determineContextInitializerClasses
(ServletContext servletContext) {
List>> classes = new ArrayList<>();
String globalClassNames = servletContext.getInitParameter(GLOBAL_INITIALIZER_CLASSES_PARAM);
if (globalClassNames != null) {
for (String className : StringUtils.tokenizeToStringArray(globalClassNames, INIT_PARAM_DELIMITERS)) {
classes.add(loadInitializerClass(className));
}
}
String localClassNames = servletContext.getInitParameter(CONTEXT_INITIALIZER_CLASSES_PARAM);
if (localClassNames != null) {
for (String className : StringUtils.tokenizeToStringArray(localClassNames, INIT_PARAM_DELIMITERS)) {
classes.add(loadInitializerClass(className));
}
}
return classes;
}
@SuppressWarnings("unchecked")
private Class> loadInitializerClass(String
className) {
try {
Class clazz = ClassUtils.forName(className, this.getClass().getClassLoader());
Assert.isAssignable(ApplicationContextInitializer.class, clazz);
return (Class>) clazz;
} catch (ClassNotFoundException ex) {
try {
throw new Exception("Failed to load context initializer class [" + className + "]", ex);
} catch (Exception e) {
e.printStackTrace();
}
}
return null;
}
// 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;
// }
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();
// }
}
}
public static WebApplicationContext getCurrentWebApplicationContext() {
ClassLoader ccl = Thread.currentThread().getContextClassLoader();
if (ccl != null) {
WebApplicationContext ccpt = currentContextPerThread.get(ccl);
if (ccpt != null) {
return ccpt;
}
}
return currentContext;
}
}
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