幾種spring 獲取bean的方法

得到spring裏註冊Bean的四種方法，特別是第三種方法，簡單： 

一：方法一（多在struts框架中）繼承BaseDispatchAction 

 

import com.mas.wawacommunity.wap.service.UserManager;

 

public class BaseDispatchAction extends DispatchAction {

    /**

    * web應用上下文環境變量

    */

    protected WebApplicationContext ctx;

 

    protected UserManager userMgr;

 

    /**

    * 得到註冊Bean     

    * @param beanName String 註冊Bean的名稱

    * @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：方法二實現BeanFactoryAware 

必定要在spring.xml中加上:

<bean id="serviceLocator" class="com.am.oa.commons.service.ServiceLocator" singleton="true" />

當對serviceLocator實例時就自動設置BeanFactory,以便後來可直接用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;

    }

 

    /**

    * 根據提供的bean名稱獲得相應的服務類     

    * @param servName bean名稱     

    */

    public static Object getService(String servName) {

        return beanFactory.getBean(servName);

    }

 

    /**

    * 根據提供的bean名稱獲得對應於指定類型的服務類

    * @param servName bean名稱

    * @param clazz 返回的bean類型,若類型不匹配,將拋出異常

    */

    public static Object getService(String servName, Class clazz) {

        return beanFactory.getBean(servName, clazz);

    }

}

 

action調用: 

 

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：方法三實現ApplicationContextAware 

必定要在spring.xml中加上:

<bean id="SpringContextUtil " class="com.am.oa.commons.service.SpringContextUtil " singleton="true" />

當對SpringContextUtil 實例時就自動設置applicationContext,以便後來可直接用applicationContext

 

public class SpringContextUtil implements ApplicationContextAware {

  private static ApplicationContext applicationContext;     //Spring應用上下文環境

 

  /**

  * 實現ApplicationContextAware接口的回調方法，設置上下文環境   

  * @param applicationContext

  * @throws BeansException

  */

  public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {

    SpringContextUtil.applicationContext = applicationContext;

  }

 

  /**

  * @return ApplicationContext

  */

  public static ApplicationContext getApplicationContext() {

    return applicationContext;

  }

 

  /**

  * 獲取對象   

  * @param name

  * @return Object 一個以所給名字註冊的bean的實例

  * @throws BeansException

  */

  public static Object getBean(String name) throws BeansException {

    return applicationContext.getBean(name);

  }

  /**

  * 獲取類型爲requiredType的對象

  * 若是bean不能被類型轉換，相應的異常將會被拋出（BeanNotOfRequiredTypeException）

  * @param name       bean註冊名

  * @param requiredType 返回對象類型

  * @return Object 返回requiredType類型對象

  * @throws BeansException

  */

  public static Object getBean(String name, Class requiredType) throws BeansException {

    return applicationContext.getBean(name, requiredType);

  }

 

  /**

  * 若是BeanFactory包含一個與所給名稱匹配的bean定義，則返回true 

  * @param name

  * @return boolean

  */

  public static boolean containsBean(String name) {

    return applicationContext.containsBean(name);

  }

 

  /**

  * 判斷以給定名字註冊的bean定義是一個singleton仍是一個prototype。

  * 若是與給定名字相應的bean定義沒有被找到，將會拋出一個異常（NoSuchBeanDefinitionException）   

  * @param name

  * @return boolean

  * @throws NoSuchBeanDefinitionException

  */

  public static boolean isSingleton(String name) throws NoSuchBeanDefinitionException {

    return applicationContext.isSingleton(name);

  }

 

  /**

  * @param name

  * @return Class 註冊對象的類型

  * @throws NoSuchBeanDefinitionException

  */

 public static Class getType(String name) throws NoSuchBeanDefinitionException {

    return applicationContext.getType(name);

  }

 

  /**

  * 若是給定的bean名字在bean定義中有別名，則返回這些別名   

  * @param name

  * @return

  * @throws NoSuchBeanDefinitionException

  */

  public static String[] getAliases(String name) throws NoSuchBeanDefinitionException {

    return applicationContext.getAliases(name);

  }

}

 

 

action調用： 

package com.anymusic.oa.webwork;

 

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(); 

//不用再加載springContext.xml文件,由於在web.xml中配置了,在程序中啓動是就有了.    

    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.經過servlet 或listener設置spring的ApplicationContext,以便後來引用.

注意分別extends  ContextLoaderListener和ContextLoaderServlet .而後就可用SpringContext來getBean.

覆蓋原來在web.xml中配置的listener或servlet.

public class SpringContext  {

  private static ApplicationContext applicationContext;     //Spring應用上下文環境

 

  */

  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()));

    }

}