spring 几种获得bean的方法
2015-05-16 10:37
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获得spring里注册Bean的四种方法,特别是第三种方法,简单: 一:方法一(多在struts框架中)继承BaseDispatchAction
public class BaseDispatchAction extends DispatchAction { /** * web应用上下文环境变量 */ protected WebApplicationContext ctx; protected UserManager userMgr; /** * 获得注册Bean * @param beanName String 注册Bean的名称 * @return */ protected final Object getBean(String beanName) { return ctx.getBean(beanName); } protected ActionForward unspecified(ActionMapping mapping, ActionForm form, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) { return mapping.findForward("index"); } public void setServlet(ActionServlet servlet) { this.servlet = servlet; this.ctx = WebApplicationContextUtils.getWebApplicationContext(servlet.getServletContext()); this.userMgr = (UserManager) getBean("userManager"); } }
二:方法二实现BeanFactoryAware 一定要在spring.xml中加上:<bean id="serviceLocator" class="com.am.oa.commons.service.ServiceLocator" singleton="true" /> 当对serviceLocator实例时就自动设置BeanFactory,以便后来可直接用beanFactory
public class ServiceLocator implements BeanFactoryAware { private static BeanFactory beanFactory = null; private static ServiceLocator servlocator = null; public void setBeanFactory(BeanFactory factory) throws BeansException { this.beanFactory = factory; } public BeanFactory getBeanFactory() { return beanFactory; } public static ServiceLocator getInstance() { if (servlocator == null) servlocator = (ServiceLocator) beanFactory.getBean("serviceLocator"); return servlocator; } /** * 根据提供的bean名称得到相应的服务类 * @param servName bean名称 */ public static Object getService(String servName) { return beanFactory.getBean(servName); } /** * 根据提供的bean名称得到对应于指定类型的服务类 * @param servName bean名称 * @param clazz 返回的bean类型,若类型不匹配,将抛出异常 */ public static Object getService(String servName, Class clazz) { return beanFactory.getBean(servName, clazz); } }
action调用:
public class UserAction extends BaseAction implements Action,ModelDriven{ private Users user = new Users(); protected ServiceLocator service = ServiceLocator.getInstance(); UserService userService = (UserService)service.getService("userService"); public String execute() throws Exception { return SUCCESS; } public Object getModel() { return user; } public String getAllUser(){ HttpServletRequest request = ServletActionContext.getRequest(); List ls=userService.LoadAllObject( Users.class ); request.setAttribute("user",ls); this.setUrl("/yonghu.jsp"); return SUCCESS; } }
三:方法三实现ApplicationContextAware 一定要在spring.xml中加上:<bean id="SpringContextUtil " class="com.am.oa.commons.service.SpringContextUtil " singleton="true" /> 当对SpringContextUtil 实例时就自动设置applicationContext,以便后来可直接用applicationContext
public class SpringContextUtil implements ApplicationContextAware { private static ApplicationContext applicationContext; //Spring应用上下文环境 /** * 实现ApplicationContextAware接口的回调方法,设置上下文环境 * @param applicationContext * @throws BeansException */ public void setApplicationContext(ApplicationContext applicationContext) throws BeansException { SpringContextUtil.applicationContext = applicationContext; } /** * @return ApplicationContext */ public static ApplicationContext getApplicationContext() { return applicationContext; } /** * 获取对象 * @param name * @return Object 一个以所给名字注册的bean的实例 * @throws BeansException */ public static Object getBean(String name) throws BeansException { return applicationContext.getBean(name); } /** * 获取类型为requiredType的对象 * 如果bean不能被类型转换,相应的异常将会被抛出(BeanNotOfRequiredTypeException) * @param name bean注册名 * @param requiredType 返回对象类型 * @return Object 返回requiredType类型对象 * @throws BeansException */ public static Object getBean(String name, Class requiredType) throws BeansException { return applicationContext.getBean(name, requiredType); } /** * 如果BeanFactory包含一个与所给名称匹配的bean定义,则返回true * @param name * @return boolean */ public static boolean containsBean(String name) { return applicationContext.containsBean(name); } /** * 判断以给定名字注册的bean定义是一个singleton还是一个prototype。 * 如果与给定名字相应的bean定义没有被找到,将会抛出一个异常(NoSuchBeanDefinitionException) * @param name * @return boolean * @throws NoSuchBeanDefinitionException */ public static boolean isSingleton(String name) throws NoSuchBeanDefinitionException { return applicationContext.isSingleton(name); } /** * @param name * @return Class 注册对象的类型 * @throws NoSuchBeanDefinitionException */ public static Class getType(String name) throws NoSuchBeanDefinitionException { return applicationContext.getType(name); } /** * 如果给定的bean名字在bean定义中有别名,则返回这些别名 * @param name * @return * @throws NoSuchBeanDefinitionException */ public static String[] getAliases(String name) throws NoSuchBeanDefinitionException { return applicationContext.getAliases(name); } }
action调用:
import java.util.List; import java.util.Map; import javax.servlet.http.HttpServletRequest; import com.anymusic.oa.commons.service.ServiceLocator; import com.anymusic.oa.hibernate.pojo.Role; import com.anymusic.oa.hibernate.pojo.Users; import com.anymusic.oa.spring.IUserService; import com.opensymphony.webwork.ServletActionContext; import com.opensymphony.xwork.Action; import com.opensymphony.xwork.ActionContext; import com.opensymphony.xwork.ModelDriven; public class UserAction extends BaseAction implements Action,ModelDriven{ private Users user = new Users(); //不用再加载springContext.xml文件,因为在web.xml中配置了,在程序中启动是就有了. UserService userService = (UserService) SpringContextUtil.getBean("userService"); public String execute() throws Exception { return SUCCESS; } public Object getModel() { return user; } public String getAllUser(){ HttpServletRequest request = ServletActionContext.getRequest(); List ls=userService.LoadAllObject( Users.class ); request.setAttribute("user",ls); this.setUrl("/yonghu.jsp"); return SUCCESS; } }
四.通过servlet 或listener设置spring的ApplicationContext,以便后来引用. 注意分别extends ContextLoaderListener和ContextLoaderServlet .然后就可用SpringContext来getBean. 覆盖原来在web.xml中配置的listener或servlet.
public class SpringContext { private static ApplicationContext applicationContext; //Spring应用上下文环境 */ public void setApplicationContext(ApplicationContext applicationContext) throws BeansException { SpringContextUtil.applicationContext = applicationContext; } /** * @return ApplicationContext */ public static ApplicationContext getApplicationContext() { return applicationContext; } */ public static Object getBean(String name) throws BeansException { return applicationContext.getBean(name); } } public class SpringContextLoaderListener extends ContextLoaderListener{ // public void contextInitialized(ServletContextEvent event) { super.contextInitialized(event); SpringContext.setApplicationContext( WebApplicationContextUtils.getWebApplicationContext(event.getServletContext()) ); } } public class SpringContextLoaderServlet extends ContextLoaderServlet { private ContextLoader contextLoader; public void init() throws ServletException { this.contextLoader = createContextLoader(); SpringContext.setApplicationContext(this.contextLoader.initWebApplicationContext(getServletContext())); } }
转自:http://jitaguizhao.iteye.com/blog/223832
参考:http://jsjxqjy.iteye.com/blog/550754
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