$.ajax({
type: "get",
url: baseUrl + "/jsonp/get",
dataType: "jsonp",
success: function(response) {
$("#response").val(JSON.stringify(response));
}
});

@ControllerAdvice
public class JsonpAdvice extends AbstractJsonpResponseBodyAdvice {
  public JsonpAdvice(){
    // 这样如果请求中带 callback 参数，Spring 就知道这个是 jsonp 的请求了
    super("callback");
  }
}

@ControllerAdvice
public class JsonpAdvice extends AbstractJsonpResponseBodyAdvice {
  public JsonpAdvice(){
    // 这样如果请求中带 callback 参数，Spring 就知道这个是 jsonp 的请求了
    super("callback");
  }
}

$.ajax({
  type: "POST",
  url: baseUrl + "/jsonp/post",
  dataType: 'json',
  crossDomain: true,
  xhrFields: {
    withCredentials: true
  },
  data: {
    name: "name_from_frontend"
  },
  success: function (response) {
    console.log(response)// 返回的 json 数据
    $("#response").val(JSON.stringify(response));
  }
});

@Configuration
public class WebConfig extends WebMvcConfigurerAdapter {
 
  @Override
  public void addCorsMappings(CorsRegistry registry) {
    registry.addMapping("/**/*").allowedOrigins("*");
  }
}

public class CrossDomainFilter extends OncePerRequestFilter {
  @Override
  protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
    response.addHeader("Access-Control-Allow-Origin", "*");// 如果提示 * 不行，请往下看
    response.addHeader("Access-Control-Allow-Credentials", "true");
    response.addHeader("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE");
    response.addHeader("Access-Control-Allow-Headers", "Content-Type");
    filterChain.doFilter(request, response);
  }
}

<filter>
  <filter-name>CrossDomainFilter</filter-name>
  <filter-class>com.javadoop.filters.CrossDomainFilter</filter-class>
</filter>
<filter-mapping>
  <filter-name>CrossDomainFilter</filter-name>
  <url-pattern>/*</url-pattern>
</filter-mapping>

String referer = request.getHeader("referer");
if (StringUtils.isNotBlank(referer)) {
  URL url = new URL(referer);
  String origin = url.getProtocol() + "://" + url.getHost();
  response.addHeader("Access-Control-Allow-Origin", origin);
} else {
  response.addHeader("Access-Control-Allow-Origin", "*");
}

function createCORSRequest(method, url) {
  var xhr = new XMLHttpRequest();
  if ("withCredentials" in xhr) {
    // 如果有 withCredentials 这个属性，那么可以肯定是 XMLHTTPRequest2 对象。看第三个参数
    xhr.open(method, url, true);
  } else if (typeof XDomainRequest != "undefined") {
    // 此对象是 IE 用来跨域请求的
    xhr = new XDomainRequest();
    xhr.open(method, url);
  } else {
    // 如果是这样，很不幸，浏览器不支持 CORS
    xhr = null;
  }
  return xhr;
}
 
var xhr = createCORSRequest('GET', url);
if (!xhr) {
  throw new Error('CORS not supported');
}