ClassPathXmlApplicationContext源码解读

入口函数

通过ClassPathXmlApplicationContext类构造方法启动父类AbstractApplicationContext的函数refresh方法

ClassPathXmlApplicationContext源码：

package org.springframework.context.support;
​
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
​
public class ClassPathXmlApplicationContext extends AbstractXmlApplicationContext {
   @Nullable
   private Resource[] configResources;
​
   public ClassPathXmlApplicationContext() {
   }
​
   public ClassPathXmlApplicationContext(ApplicationContext parent) {
       super(parent);
   }
​
   public ClassPathXmlApplicationContext(String configLocation) throws BeansException {
       this(new String[]{configLocation}, true, (ApplicationContext)null);
   }
​
   public ClassPathXmlApplicationContext(String... configLocations) throws BeansException {
       this(configLocations, true, (ApplicationContext)null);
   }
​
   public ClassPathXmlApplicationContext(String[] configLocations, @Nullable ApplicationContext parent) throws BeansException {
       this(configLocations, true, parent);
   }
​
   public ClassPathXmlApplicationContext(String[] configLocations, boolean refresh) throws BeansException {
       this(configLocations, refresh, (ApplicationContext)null);
   }
​
   public ClassPathXmlApplicationContext(String[] configLocations, boolean refresh, @Nullable ApplicationContext parent) throws BeansException {
       super(parent);
       this.setConfigLocations(configLocations);
       if (refresh) {
           this.refresh();
       }
​
   }
​
   public ClassPathXmlApplicationContext(String path, Class<?> clazz) throws BeansException {
       this(new String[]{path}, clazz);
   }
​
   public ClassPathXmlApplicationContext(String[] paths, Class<?> clazz) throws BeansException {
       this(paths, clazz, (ApplicationContext)null);
   }
​
   public ClassPathXmlApplicationContext(String[] paths, Class<?> clazz, @Nullable ApplicationContext parent) throws BeansException {
       super(parent);
       Assert.notNull(paths, "Path array must not be null");
       Assert.notNull(clazz, "Class argument must not be null");
       this.configResources = new Resource[paths.length];
​
       for(int i = 0; i < paths.length; ++i) {
           this.configResources[i] = new ClassPathResource(paths[i], clazz);
       }
​
       this.refresh();
   }
​
   @Nullable
   protected Resource[] getConfigResources() {
       return this.configResources;
   }
}
​

ClassPathXmlApplicationContext(String configLocation) 一般使用这个方法，传入一个string类型的xml文件名，通过xml配置文件指定特定的组件，实例化到bean工厂里，即DefaultSingletonBeanRegistry 下的Map集合里

ClassPathXmlApplicationContext(String... configLocations)：可传入多个xml，装配到spring，bean工厂

public ClassPathXmlApplicationContext(String[] configLocations, boolean refresh) :传入String数组

@Test
    public void TestXmlBean(){
        ClassPathXmlApplicationContext context =new ClassPathXmlApplicationContext("classpath:xmlRegBean.xml");
        Animal cat =context.getBean("cat", Cat.class);
        cat.getName();
   }
​
   @Test
   public void TestMultiXml(){
           ClassPathXmlApplicationContext context =new ClassPathXmlApplicationContext("classpath:xmlRegBean.xml","classpath:xmlRegBean2.xml");
           Animal cat =context.getBean("cat", Cat.class);
           cat.getName();
           System.out.println(cat);
           Animal cat2 =context.getBean("cat2", Cat.class);
           cat2.getName();
           System.out.println(cat2);
   }
    
 @Test
   public void TestArrayXml(){
       String[] arrXml = {"classpath:xmlRegBean.xml","classpath:xmlRegBean2.xml"};
       ClassPathXmlApplicationContext context =new ClassPathXmlApplicationContext(arrXml,true);
       Animal cat =context.getBean("cat", Cat.class);
       cat.getName();
       System.out.println(cat);
       Animal cat2 =context.getBean("cat2", Cat.class);
       cat2.getName();
       System.out.println(cat2);
   }