关于Java项目读取resources资源文件路径的那点事

File file = new File("src/main/resources/properties/test.properties");
InputStream in = new FileInputStream(file);

InputStream in = this.getClass().getResourceAsStream("/properties/test.properties");
Properties properties = new Properties();
properties.load(in);
properties.getProperty("name");

1) InputStream inStream = PropertiesTest.class.getResourceAsStream("test.properties");
2) inStream = PropertiesTest.class.getResourceAsStream("/com/test/demo/test.properties")
3) inStream = PropertiesTest.class.getClassLoader().getResourceAsStream("com/test/demo/test.properties");

public InputStream getResourceAsStream(String name) {
        name = resolveName(name);
        ClassLoader cl = getClassLoader0();
        if (cl==null) {
            // A system class.
            return ClassLoader.getSystemResourceAsStream(name);
        }
        return cl.getResourceAsStream(name);
 }

inStream = PropertiesTest.class.getClassLoader().getResourceAsStream("com/test/demo/test.properties");

inStream = PropertiesTest.class.getResourceAsStream("/com/test/demo/test.properties")

 <context:component-scan base-package="com.xxxx.service"/>
 <context:property-placeholder location="classpath:properties/xxx.properties" ignore-unresolvable="true"/>

 @Value("${xxxt.server}")
 private static String serverUrl;

<?xml version="1.0" encoding="UTF-8"?>
  <beans xmlns="http://www.springframework.org/schema/beans"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://www.springframework.org/schema/beans 
      http://www.springframework.org/schema/beans/spring-beans-4.0.xsd">
      <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
          <property name="location" value="classpath:properties/xxx.properties"/>
      </bean>
     <bean id="service" class="com.xxxx.service.ServiceImpl">         <property name="serverUrl" value="${xxxt.server}" />
     </bean>
 </beans>

InputStream inputStream = EncryptUtil.class.getResourceAsStream("/HelloServiceEncryptFile.txt");
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
String line = reader.readLine();
// 获取类路径下的文件路径
File path = new File(ResourceUtils.getURL("classpath:").getPath());
if (!path.exists()) {
   path = new File("");
}
log.info("path = {}", path.getAbsolutePath());
File upload = new File(path.getAbsolutePath(), "com/study/service");
if (!upload.exists()) {
    upload.mkdirs();
}
FileOutputStream fos = new FileOutputStream(upload.getAbsolutePath() + File.separator + "hello.txt");
IoUtil.copy(inputStream, fos);
fos.close();
inputStream.close();