zoukankan      html  css  js  c++  java
  • Spring框架里解析配置文件的准确位置

    We can define bean configuration in xml and then can get instantiated bean instance with help of all kinds of containers for example ClassPathXmlApplicationContext as displayed below:

    The content of Beans.xml:

    <?xml version="1.0" encoding="UTF-8"?>
    <!--  http://stackoverflow.com/questions/18802982/no-declaration-can-be-found-for-element-contextannotation-config
     -->
    <beans xmlns="http://www.springframework.org/schema/beans"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns:context="http://www.springframework.org/schema/context"
        xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context.xsd">   
       <bean id="helloWorld" class="main.java.com.sap.HelloWorld">
           <property name="message" value="sss"/>
           <property name="testMin" value="2"/>
           <property name="phone" value="1"/>
       </bean>
    </beans>
    

    Where can we set breakpoint to start? No hint. Here is a tip: we can make the Beans.xml invalid by deliberately changing te tag bean to beana, and relaunch application. Now exception is raised as expected: Click the hyperlink XmlBeanDefinitionReader.java:399,

    The line 399 where exception is raised will be automatically located. The core logic to load xml file is just near the exception raise position: line 391. So we can set breakpoint in line 391 now:

    Change the tag from beana back to bean, and start application via debug mode. The code below is the core logic of Bean configuration file parse in Spring framework. The logic consists of two main steps:

    (1) parse XML as a dom structure in memory ( line 391 )
    (2) extract bean information contained in dom structure and generate BeanDefinition structure ( line 392 )

    from screenshot below we can find out the xml is parsed via SAX parser:

    My “helloWorld” bean is parsed here:


    要获取更多Jerry的原创文章,请关注公众号"汪子熙":

  • 相关阅读:
    类加载器
    java类的主动使用方式
    Java类装载器和命名空间
    cas改造
    所有jar文件列出工具
    源码阅读工具_解析所有类的使用情况
    web(s,哈哈,w,没有,d,用处,f)web框架引用类的次数
    struts2类型转换器StrutsTypeConverter的使用
    struts2的验证框架的使用和扩展
    Python3连接MySQL
  • 原文地址:https://www.cnblogs.com/sap-jerry/p/13549156.html
Copyright © 2011-2022 走看看