getResourceAsStream返回NullpointException(spring4)

Question

@RequestMapping(value = "/all", method = RequestMethod.GET)
public ResponseEntity<List<ItemVO>> listAll() {
    ResponseEntity<List<ItemVO>> entity = null;
    try {


        List<ItemVO> list=service.listAll();
        for(ItemVO i : list){
            InputStream in = getClass().getClassLoader().getResourceAsStream(i.getFilepath_img()); 

            i.setByte_img(IOUtils.toByteArray(in));

        }
          final HttpHeaders headers = new HttpHeaders();
            headers.setContentType(MediaType.IMAGE_PNG);
        entity = new ResponseEntity<List<ItemVO>>(list, HttpStatus.OK);

    } catch (Exception e) {
        // TODO: handle exception
        e.printStackTrace();
        entity = new ResponseEntity<>(HttpStatus.BAD_REQUEST);
    }

    return entity;
}

 public class ItemVO{
    private int item_id;
    private String filepath_img;
    private byte[] byte_img;
}

我不知道如何进行堆栈跟踪：

NullPointerException

at org.apache.commons.io.IOUtils.copyLarge(IOUtils.java:2146)

at org.apache.commons.io.IOUtils.copy(IOUtils.java:2102)

at org.apache.commons.io.IOUtils.copyLarge(IOUtils.java:2123)

at org.apache.commons.io.IOUtils.copy(IOUtils.java:2078)

at org.apache.commons.io.IOUtils.toByteArray(IOUtils.java:721)

Answer 1

webapp/resources/..不在类路径中。您可以通过使用ServletContext来解决这个问题

注射：

@Autowired
private ServletContext servletContext;

然后获取inputstream:

InputStream in = servletContext.getResourceAsStream(i.getFilepath_img()); 

null