Spring注入Servlet [英] Spring injection Into Servlet

问题描述

所以我看到这个问题：

Spring依赖注入到其他实例

，并且想知道我的方法是否可行。

and was wondering if my method will work out.

1）在我的Spring应用程序上下文中声明bean

1) Declare beans in my Spring application context

    <bean id="dataSource" destroy-method="close" class="org.apache.commons.dbcp.BasicDataSource">
        <property name="driverClassName" value="${jdbc.driverClassName}"/>
        <property name="url" value="${jdbc.url}" />
        <property name="username" value="${jdbc.username}" />
        <property name="password" value="${jdbc.password}" />
        <property name="initialSize" value="${jdbc.initialSize}" />
        <property name="validationQuery" value="${jdbc.validationQuery}" /> 
        <property name="testOnBorrow" value="${jdbc.testOnBorrow}" />
    </bean>

    <bean id="apiData" class="com.mydomain.api.data.ApiData">
        <property name="dataSource" ref="dataSource" />
        <property name="apiLogger" ref="apiLogger" />
    </bean>

    <bean id="apiLogging" class="com.mydomain.api.data.ApiLogger">
        <property name="dataSource" ref="dataSource" />
    </bean>

2）覆盖我的servlet的init方法，如图所示：

2) Override my servlet's init method as shown:

    @Override
    public void init(ServletConfig config) throws ServletException {
       super.init(config);

       ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");

       this.apiData = (ApiData)ac.getBean("apiData");
       this.apiLogger = (ApiLogger)ac.getBean("apiLogger");
    }

这个工作还是Spring还没准备好将bean发送到我的servlet这一点在Web应用程序中部署？我必须做一些更传统的东西，比如将豆放在 web.xml 中。

Will this work or is Spring not yet ready to deliver beans to my servlet at this point in the web applications deployment? Do I have to do something more traditional like putting the beans in web.xml?

推荐答案

你要做的是使每个 Servlet 有自己的 ApplicationContext 实例。也许这是你想要的，但我怀疑。一个 ApplicationContext 应该是应用程序唯一的。

What you are trying to do will make every Servlet have its own ApplicationContext instance. Maybe this is what you want, but I doubt it. An ApplicationContext should be unique to an application.

正确的方法是设置你的 ApplicationContext 在 ServletContextListener 。

The appropriate way to do this is to setup your ApplicationContext in a ServletContextListener.

public class SpringApplicationContextListener implements ServletContextListener {
        @Override
    public void contextInitialized(ServletContextEvent sce) {
        ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");

        sce.getServletContext().setAttribute("applicationContext", ac);            
    }
    ... // contextDestroyed
}

现在所有servlet都可以通过 ServletContext 属性访问相同的 ApplicationContext 。

Now all your servlets have access to the same ApplicationContext through the ServletContext attributes.

@Override
public void init(ServletConfig config) throws ServletException {
   super.init(config);

   ApplicationContext ac = (ApplicationContext) config.getServletContext().getAttribute("applicationContext");

   this.apiData = (ApiData)ac.getBean("apiData");
   this.apiLogger = (ApiLogger)ac.getBean("apiLogger");
}

这篇关于Spring注入Servlet的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！