Java_web开发_SSH spring中取得Bean实例的方法

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

 

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

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="项目中ServiceLocator的类路径比如：com.am.oa.commons.service.SpringContextUtil " 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="项目中applicationContext的类路径比如：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： 

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()));
}
}

  

 

自己使用：

 

1.如果applicationContext文件是在src的根目录下：

  ApplicationContext apt= new FileSystemXmlApplicationContext("src/applicationContext.xml");

apt.getBean("ID");

可以取得

 

2.如果文件是在WebRoot/WEB-INF下可以用

ApplicationContext applicationContext= new FileSystemXmlApplicationContext("../applicationContext.xml");

取得

 

3.如果是在servlet中取可用

  ServletContext application = this.getServletContext();
  
  //获取spring上下文信息 为servlet使用
  WebApplicationContext wac = WebApplicationContextUtils.getWebApplicationContext(application);
  IDicService dicService = (IDicService)wac.getBean("dicService");