具有Java后端API和angular前端的Access-Control-Allow-Origin标头

Question

在控制台中运行我的Angular HTTP Get请求时，出现以下错误：

CORS策略已阻止从来源“ http://localhost:4200”访问“ [url]”处的XMLHttpRequest：请求的资源上没有“ Access-Control-Allow-Origin”标头。

我在后端使用了下面的代码，但这不能解决问题。我见过像js语法这样的实现。我需要正确的Java / Angular配置。

app.use(function (req, res, next) {
  res.setHeader('Access-Control-Allow-Origin', '*');
  res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS, PUT, PATCH, DELETE');
  res.setHeader('Access-Control-Allow-Credentials', true);
  next();
});
``````````````````````````
private void configureCors(Environment environment) {
        final FilterRegistration.Dynamic cors =
                environment.servlets().addFilter("CORS", CrossOriginFilter.class);

        // Configure CORS parameters
        cors.setInitParameter(CrossOriginFilter.ALLOWED_ORIGINS_PARAM, "*");
        cors.setInitParameter(CrossOriginFilter.ALLOWED_HEADERS_PARAM, "X-Requested-With,Content-Type,Accept,Origin,Authorization");
        cors.setInitParameter(CrossOriginFilter.ALLOWED_METHODS_PARAM, "OPTIONS,GET,PUT,POST,DELETE,HEAD");
        cors.setInitParameter(CrossOriginFilter.ALLOW_CREDENTIALS_PARAM, "true");

        // Add URL mapping
        cors.addMappingForUrlPatterns(EnumSet.allOf(DispatcherType.class), true, "/*");

    }
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