Java读取properties配置文件

这里介绍两种技术：利用spring读取properties 文件和利用java.util.Properties读取

(一)利用spring读取properties 文件

利用org.springframework.beans.factory.support.PropertiesBeanDefinitionReader来读取属性文件

构造如下config.properties文件properties代码
userDao.class=com.spring.dao.UserDao 

属性文件中的"userDao"名称即是Bean的别名设定，.class用于指定类来源。
然后利用org.springframework.beans.factory.support.PropertiesBeanDefinitionReader来读取属性文件

   BeanDefinitionRegistry reg = new DefaultListableBeanFactory();

   PropertiesBeanDefinitionReader reader = new PropertiesBeanDefinitionReader(reg);

   reader.loadBeanDefinitions(new ClassPathResource("config.properties"));

   BeanFactory factory = (BeanFactory)reg;

   UserDao userDao = (UserDao)factory.getBean("userDao");
(二)利用java.util.Properties读取属性文件

1.    String str=File.separator;

        InputStream path=this.getServletContext().getResourceAsStream(str+"WEB-INF"+str+"classes"+str+"password.properties");
        //InputStream inputStream = this.getClass().getClassLoader().getResourceAsStream("password.properties");

    /*File filepath=new File(this.getServletContext().getRealPath(str+"WEB-INF"+str+"classes")+str+"password.properties");

        InputStream path=new FileInputStream(filepath);*/

        Properties pros = new Properties();

        try {

            pros.load(path);

        } catch (IOException ex) {

            //System.out.println("file is not exist");

            errorMessage="资源文件不存在";
        }

        System.out.println("username:"+p.getProperty("username")+",password:"+p.getProperty("password"));

2.    import org.springframework.core.io.ClassPathResource;

        ClassPathResource cr = new ClassPathResource("password.properties");//会重新加载spring框架

        Properties pros = new Properties();

        try {

            pros.load(cr.getInputStream());

        } catch (IOException ex) {

            //System.out.println("file is not exist");

            errorMessage="资源文件不存在";

        }