Spring如何从资源文件夹中读取文件呢?

Spring从资源文件夹中读取文件的实现思路

Spring中
    使用ClassPathResource或ResourceLoader
	  可从classpath中获取文件

ClassPathResource

   import org.springframework.core.io.Resource;
   import org.springframework.core.io.ClassPathResource;
   import java.io.File;  
   import java.io.InputStream;

	Resource resource = new ClassPathResource("img.png");
	InputStream input = resource.getInputStream();
	File file = resource.getFile();

ResourceLoader

	import org.springframework.core.io.Resource;
	import org.springframework.core.io.ResourceLoader;
 
	import java.io.File;
	import java.io.InputStream;
 
	@Autowired
    ResourceLoader resourceLoader;
	
	Resource resource = resourceLoader.getResource("classpath:img.png");
	InputStream input = resource.getInputStream();
	File file = resource.getFile();

ResourceUtils
import org.springframework.util.ResourceUtils;
 
 File file = ResourceUtils.getFile("classpath:img.png");