SpringBoot程序中加载资源文件的几种方式

Posted by zhida on May 22, 2016

加载资源文件

@Value("mq_service.properties")
private ClassPathResource resource;

Properties properties = null;
try {
	InputStream in = resource.getInputStream();
	properties = new Properties();
	properties.load(in);
} catch (IOException e) {
	e.printStackTrace();
}

如果报Null Exception ,并且实现 BeanFactoryPostProcessor

不要实现BeanFactoryPostProcessor接口,使用注释

@postConstruct

原生代码形式

InputStream in = MqCoreService.class.getClassLoader().getResourceAsStream("mq_service.properties");

war 读取

Resource resource = ResourceLoader.getResource("classpath:GeoLite2-Country.mmdb");
File dbAsFile = resource.getFile();

Load file from JAR

Use ClassLoader#getResource() instead if its URI represents a valid local disk file system path.

URL resource = classLoader.getResource("resource.ext");
File file = new File(resource.toURI());
FileInputStream input = new FileInputStream(file);

If it doesn’t (e.g. JAR), then your best bet is to copy it into a temporary file.

Path temp = Files.createTempFile("resource-", ".ext");
Files.copy(classLoader.getResourceAsStream("resource.ext"), temp, StandardCopyOption.REPLACE_EXISTING);
FileInputStream input = new FileInputStream(temp.toFile());
// ...

RSA.class.getClassLoader() = classLoader

Load file from Spring Boot JAR (亲测无效)

Resource resource = resourceLoader.getResource("classpath:GeoLite2-Country.mmdb");
InputStream dbAsStream = resource.getInputStream(); // <-- this is the difference

参考网站

Java: Load file from classpath in Spring Boot How to convert InputStream to FileInputStream