SpringBoot前后端分离的跨域问题

前端报错：has been blocked by CORS policy: No ‘Access-Control-Allow-Origin’ header is

解决代码：
CorsConfig.java

@Configuration
public class CorsConfig extends WebMvcConfigurerAdapter {

@Override
public void addCorsMappings(CorsRegistry registry) {
// TODO Auto-generated method stub
// super.addCorsMappings(registry);
registry.addMapping("/**")
.allowedOrigins("*")
.allowCredentials(true)
.allowedMethods("GET", "POST", "DELETE", "PUT")
.maxAge(3600);
}

@Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {

MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter = new MappingJackson2HttpMessageConverter();
//设置日期格式
ObjectMapper objectMapper = new ObjectMapper();
SimpleDateFormat smt = new SimpleDateFormat("yyyy-MM-dd");
objectMapper.setDateFormat(smt);
mappingJackson2HttpMessageConverter.setObjectMapper(objectMapper);
//设置中文编码格式
List<MediaType> list = new ArrayList<MediaType>();
list.add(MediaType.APPLICATION_JSON_UTF8);
mappingJackson2HttpMessageConverter.setSupportedMediaTypes(list);
converters.add(mappingJackson2HttpMessageConverter);
super.configureMessageConverters(converters);
}


}

LoginFilter.java

@Component
@ServletComponentScan
@WebFilter()
public class LoginFilter implements Filter {

@Resource
private OauthService oauthService;

@Resource
private SessionUtils tokenUtils;

private String[] ignoreUrls = null;
// 刷新患者的地址
private static final String IGNORE_URL = PropertiesBean.getInstance()
.getProperty("rivamed.security.cas.app-pattern.ignoring");

@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
HttpServletResponse response2 = (HttpServletResponse) response;
response2.setHeader("Access-Control-Allow-Origin","*");
response2.setHeader("Access-Control-Allow-Credentials", "true");
response2.setHeader("Access-Control-Allow-Methods", "POST, PUT, GET, OPTIONS, DELETE");
response2.setHeader("Access-Control-Max-Age", "5000");
response2.setHeader("Access-Control-Allow-Headers", "Origin, No-Cache, X-Requested-With, If-Modified-Since," +
" Pragma, Last-Modified, Cache-Control, Expires, Content-Type, X-E4M-With,Authorization,Token,tokenId,tokenid");
HttpServletRequest request2 = (HttpServletRequest) request;
String tokenId = request2.getHeader("tokenId");
String method = request2.getMethod();
//    Long startTime=System.currentTimeMillis();
for (String ignoreUrl : ignoreUrls) {
if (request2.getRequestURI().contains(ignoreUrl)) {
chain.doFilter(request, response2);
return;
}
}
if (UmConstants.CROSS_REQUEST_METHOD.equals(method)) {
chain.doFilter(request, response2);
return;
}
AccessToken token = oauthService.findAccessToken(tokenId);
if (null != token) {
if (token.tokenExpired() && token.refreshTokenExpired()) {
writeResponse(response2, Constants.LOGIN_EXPIRED);
return;
}
if (token.tokenExpired() && !token.refreshTokenExpired()) {
writeResponse(response2, Constants.TOKEN_EXPIRED);
return;
} else {
tokenUtils.initTokenUser(tokenId);
chain.doFilter(request, response2);
}
} else {
writeResponse(response2, Constants.LOGIN_EXPIRED);
return;
}
//    Long endTime=System.currentTimeMillis();
//    System.out.println(request2.getRequestURI()+"---used time---"+(endTime-startTime));

}

private void writeResponse(HttpServletResponse response2, String status) throws IOException {
//    HttpServletResponse response2 = (HttpServletResponse) response;
OutputStream outputStream = response2.getOutputStream();// 获取
ExeceptionDto dto = new ExeceptionDto();
dto.setOpFlg(status);
response2.setHeader("content-type", "application/json;charset=UTF-8");// 通过设置响应头控制浏览器以UTF-8的编码显示数据，如果不加这句话，那么浏览器显示的将是乱码
byte[] bs = JSONObject.toJSONBytes(dto, SerializerFeature.EMPTY);
outputStream.write(bs);// 使用OutputStream流向客户端输出字节数组
}

@Override
public void init(FilterConfig filterConfig) throws ServletException {
ignoreUrls = IGNORE_URL.split(",");
}

@Override
public void destroy() {
}

}

原理：
前后端分离,后端用SpringBoot遇到的跨域问题
https://www.jianshu.com/p/a02500ef1446