spring加载配置文件的几种方法

spring 加载配置文件的几种方法

在学习spring的过程中，加载文件报错，告诉我文件不存在：

代码：
package helloworld;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class HelloTest {
@Test
public void testHelloWorld() {
// 1、读取配置文件实例化一个IoC容器
ApplicationContext context = new ClassPathXmlApplicationContext(
"HelloWorld.xml");
// 2、从容器中获取Bean，注意此处完全“面向接口编程，而不是面向实现”
HelloApi helloApi =  context.getBean("hello",HelloApi.class);
// 3、执行业务逻辑
helloApi.sayHello();
}
}

报错：

org.springframework.beans.factory.BeanDefinitionStoreException: IOException parsing XML document from class path resource [HelloWorld.xml]; nested exception is java.io.FileNotFoundException: class path resource [HelloWorld.xml] cannot be opened because it does not exist
at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:341)
at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:302)
at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:174)
at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:209)
at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:180)
at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:243)
at org.springframework.context.support.AbstractXmlApplicationContext.loadBeanDefinitions(AbstractXmlApplicationContext.java:127)
at org.springframework.context.support.AbstractXmlApplicationContext.loadBeanDefinitions(AbstractXmlApplicationContext.java:93)
at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:131)
at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:527)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:441)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83)
at helloworld.HelloTest.testHelloWorld(HelloTest.java:11)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:49)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: java.io.FileNotFoundException: class path resource [HelloWorld.xml] cannot be opened because it does not exist
at org.springframework.core.io.ClassPathResource.getInputStream(ClassPathResource.java:157)
at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:328)
... 35 more

我是按照教程上的做的，不知道为什么我的代码不行，于是我查了一下spring加载配置文件的方法：
一：Spring中的几种容器都支持使用xml装配bean，包括：
XmlBeanFactory ，
ClassPathXmlApplicationContext ，
FileSystemXmlApplicationContext ，
XmlWebApplicationContext
加载这些容器的配置文件的xml有一下几种常见的方法：
1：引用资源用XmlBeanFactory（不能实现多个文件相互引用）
Resource resource = new ClassPathResource("HelloWorld.xml");
BeanFactory factory = new XmlBeanFactory(resource);
从factory中获取相应资源文件中的bean，但是这种bean读不到引用了其他文件中的bean！
2：引用应用上下文用ClassPathXmlApplicationContext
ApplicationContext factory=new ClassPathXmlApplicationContext("classpath:applicationContext.xml");
ApplicationContext factory=new ClassPathXmlApplicationContext("conf/userConfig.xml"); // src/conf 目录下的
ApplicationContext factory=new ClassPathXmlApplicationContext("file:G:/Test/src/appcontext.xml");
3：用文件系统的路径引用应用上下文用FileSystemXmlApplicationContext
ApplicationContext factory=new FileSystemXmlApplicationContext("src/applicationContext.xml");
ApplicationContext factory=new FileSystemXmlApplicationContext("classpath:appcontext.xml");
ApplicationContext factory=new FileSystemXmlApplicationContext("file:G:/Test/src/appcontext.xml");
ApplicationContext factory=new FileSystemXmlApplicationContext("G:/Test/src/appcontext.xml");
注意：在2、3的加载方式中可以加载多个配置文件，获取到ApplicationContext 对象中
String[] configs = {"applicationContext.xml","user_spring.xml"};
ApplicationContext ctx = new ClassPathXmlApplicationContext(configs);
//ApplicationContext ctx=new FileSystemXmlApplicationContext(configs);
AbstractDao myUserDAO = (AbstractDao) ctx.getBean("userDao");
4：Web工程定制的加载方法 XmlWebApplicationContext
ServletContext servletContext = request.getSession().getServletContext();
ApplicationContext ctx = WebApplicationContextUtils.getWebApplicationContext(servletContext );




一、简单的用ApplicationContext做测试的话,获得Spring中定义的Bean实例(对象).可以用:

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

如果是两个以上:
ApplicationContext ac = new ClassPathXmlApplicationContext(new String[]{"applicationContext.xml","dao.xml"});

或者用通配符:
ApplicationContext ac = new ClassPathXmlApplicationContext("classpath:/*.xml");


二、ClassPathXmlApplicationContext[只能读放在web-info/classes目录下的配置文件]和FileSystemXmlApplicationContext的区别

classpath:前缀是不需要的,默认就是指项目的classpath路径下面;
如果要使用绝对路径,需要加上file:前缀表示这是绝对路径;

对于FileSystemXmlApplicationContext:
默认表示的是两种:

1.没有盘符的是项目工作路径,即项目的根目录;
2.有盘符表示的是文件绝对路径.

如果要使用classpath路径,需要前缀classpath:

public class HelloClient {

  protected static final Log log = LogFactory.getLog(HelloClient.class);

  public static void main(String[] args) {
    // Resource resource = new ClassPathResource("appcontext.xml");
    // BeanFactory factory = new XmlBeanFactory(resource);

    // 用classpath路径
    // ApplicationContext factory = new ClassPathXmlApplicationContext("classpath:appcontext.xml");
    // ApplicationContext factory = new ClassPathXmlApplicationContext("appcontext.xml");

    // ClassPathXmlApplicationContext使用了file前缀是可以使用绝对路径的
    // ApplicationContext factory = new ClassPathXmlApplicationContext("file:F:/workspace/example/src/appcontext.xml");

    // 用文件系统的路径,默认指项目的根路径
    // ApplicationContext factory = new FileSystemXmlApplicationContext("src/appcontext.xml");
    // ApplicationContext factory = new FileSystemXmlApplicationContext("webRoot/WEB-INF/appcontext.xml");


    // 使用了classpath:前缀,这样,FileSystemXmlApplicationContext也能够读取classpath下的相对路径
    // ApplicationContext factory = new FileSystemXmlApplicationContext("classpath:appcontext.xml");
    // ApplicationContext factory = new FileSystemXmlApplicationContext("file:F:/workspace/example/src/appcontext.xml");

    // 不加file前缀
    ApplicationContext factory = new FileSystemXmlApplicationContext("F:/workspace/example/src/appcontext.xml");
    IHelloWorld hw = (IHelloWorld)factory.getBean("helloworldbean");
    log.info(hw.getContent("luoshifei"));
  }
}