关于ResponseEntity类和HttpEntity及跨平台路径问题

ResponseEntity<String> entity = template.getForEntity("https://hello.com", String.class);
String body = entity.getBody();
MediaType contentType = entity.getHeaders().getContentType();
HttpStatus statusCode = entity.getStatusCode();

@RestController
@RequestMapping("/demo")
public class DemoController {

    @GetMapping("/get")
    public ResponseEntity<String> get() {
        return ResponseEntity.ok("hello");
    }
}

@GetMapping("/get")
public ResponseEntity<String> get() {
    return ResponseEntity.status(HttpStatus.LOCKED).body("服务不可用");
}

@GetMapping("/get")
public ResponseEntity<String> get() {
    ResponseEntity responseEntity = new ResponseEntity("服务不可用", HttpStatus.LOCKED);
    return responseEntity;
}

@GetMapping("/get")
public ResponseEntity<String> get() {
    return ResponseEntity.ok()
        .header("Custom-Header", "lisa")
        .body("Custom header set");
}

 @GetMapping("/download")
    public ResponseEntity<byte[]> get() throws IOException {
        // 你放的文件路径
        String filePath = "C:" + File.separator + "Users" + File.separator + "admin002" + File.separator + "Desktop" + File.separator + "work" + File.separator + "img";
        File file = new File(filePath + File.separator + "java.png");
        // 设置一个head
        HttpHeaders headers = new HttpHeaders();
        // 文件的属性，也就是文件叫什么
        headers.setContentDispositionFormData("attachment", "1.png");
        // 内容是字节流
        headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
        // 开始下载
        return new ResponseEntity<byte[]>(FileUtils.readFileToByteArray(file), headers, HttpStatus.OK);
    }

@GetMapping("/get")
public void get(HttpServletResponse response) throws IOException {
    response.setHeader("Custom-Header", "lisa");
    response.setStatus(200);
    response.getWriter().println("Hello World!");
}