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spring实战

本文就是用，不讲任何源码，简易版手册

读取配置文件

1.<bean class="org.springframework.context.support.PropertySourcesPlaceholderConfigurer">
    <property name="locations">
        <list>
            <value>classpath*:*.properties</value>
            <value>classpath*:*/*.properties</value>
        </list>
    </property>
</bean>
----------
2.<context:property-placeholder location="classpath*:*.properties" file-encoding="UTF-8"/>

使用aspectj aop来初始化上下文

<!-- 使用aop来初始化上下文 -->
<aop:aspectj-autoproxy proxy-target-class="true"/>
    <bean id="AopForContext" class="com.xxx.util.AopForContext">
</bean>

开启spring mvc controller

  1. 如果没有@ResponseBody的话，spring mvc的返回走的是spring的视图渲染器，可以设置model，可以forword://xxxUrl?orderNo

  2. 如果有ResponseBody的话，返回return的结果，可以设置message-Converter处理返回值例如spring自带的MappingJackson2HttpMessageConverter

    <!-- Enables the Spring MVC @Controller programming model -->
<mvc:annotation-driven>
    <mvc:message-converters>	<!--支持的media类型s-->
        <bean class="org.springframework.http.converter.StringHttpMessageConverter">
            <property name="supportedMediaTypes">
                <list>
                    <value>text/plain;charset=UTF-8</value>
                    <value>text/xml;charset=UTF-8</value>
                    <value>text/html;charset=UTF-8</value>
                </list>
            </property>
        </bean>	<!--json格式的序列化与反序列化-->
        <bean id="mappingJacksonHttpMessageConverter"
              class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter">
            <property name="supportedMediaTypes">
                <list>
                    <value>application/json;charset=UTF-8</value>
                </list>
            </property>
            <property name="objectMapper">
                <bean class="org.codehaus.jackson.map.ObjectMapper">
                    <property name="serializationInclusion" value="NON_NULL"/>
                </bean>
            </property>
        </bean>
    </mvc:message-converters>
</mvc:annotation-driven>

项目根目录下的index.jsp不生效，index.jsp是纯文本输出

解决方案与说明：在controller的配置文件中添加如下，告诉spring mvc将静态资源的处理交回Web应用服务器tomcat处理。(spring mvc主要是使用restful风格的)

pathVariable

@RequestMapping(value="/comment/{blogId}", method=RequestMethod.POST)
public void comment(@PathVariable int blogId, HttpSession session) {
}

在该例子中，blogId是被@PathVariable标记为请求路径变量的，如果请求的是/blog/comment/1.do的时候就表示blogId的值为1

同样@RequestParam也是用来给参数传值的，但是它是从头request的参数里面取值，相当于request.getParameter(“参数名”)方法。 它的取值规则跟@PathVariable是一样的，当没有指定的时候，默认是从request中取名称跟后面接的变量名同名的参数值， 当要明确从request中取一个参数的时候使用@RequestParam(“参数名”)

@Scope(“prototype”)

@Component("QueryMessageTask")
@Scope("prototype")
public class QueryMessageTask  implements Callable<List<TaskInfo>>
Scope默认是singleton(单例).

map属性

<!--邮件模板-->
<bean id="velocityEngine"
      class="org.springframework.ui.velocity.VelocityEngineFactoryBean">
    <property name="resourceLoaderPath">
        <value>classpath:</value>
    </property>
    <property name="velocityProperties">
        <props>
            <prop key="input.encoding">UTF-8</prop>
            <prop key="output.encoding">UTF-8</prop>
            <prop key="contentType">text/html;charset=UTF-8</prop>
            <prop key="resource.loader">class</prop>
            <prop key="class.resource.loader.class">
                org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader
            </prop>
            <prop key="file.resource.loader.cache">false</prop>
            <prop key="file.resource.loader.modificationCheckInterval">1</prop>
            <prop key="velocimacro.library.autoreload">true</prop>
            <prop key="velocity.engine.resource.manager.cache.enabled">false</prop>
            <prop key="springMacro.resource.loader.cache">false</prop>
            <prop key="eventhandler.referenceinsertion.class">
                org.apache.velocity.app.event.implement.EscapeXmlReference
            </prop>
        </props>
    </property>
</bean>

bean的生命周期

bean的生命周期

aware接口 -> 将单向关联转化为双向关联（Change Unidirectional Association to Bidirectional），详见重构

component-scan vs annotation-config

1.<context:component-scan base-package="com.xxx">
    <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
</context:component-scan>
----------
2.<context:annotation-config/>

关于spring-bean的扫描有两个配置需要说下：

<context:annotation-config> is used to activate annotations in beans already registered in the application context (no matter if they were defined with XML or by package scanning).

<context:component-scan> can also do what <context:annotation-config> does but <context:component-scan> also scans packages to find and register beans within the application context.

both tags register the same processing tools (<context:annotation-config /> can be omitted if <context:component-scan> is specified) but Spring takes care of running them only once.

I found this nice summary of which annotations are picked up by which declarations. By studying it you will find that <context:component-scan/> recognizes a superset of annotations recognized by <context:annotation-config/>, namely: @Component, @Service, @Repository, @Controller, @Endpoint @Configuration, @Bean, @Lazy, @Scope, @Order, @Primary, @Profile, @DependsOn, @Import, @ImportResource. As you can see

logically extends with CLASSPATH component scanning and Java @Configuration features.

ApplicationListener

Constructor > @PostConstruct > InitializingBean > init-method，构造函数最优先

参考

component-scan-vs-annotation-config scope