java后台调用接口及处理跨域问题的解决

public String httpPost(String urlStr,Map<String,String> params){
    URL connect;
    StringBuffer data = new StringBuffer();  
    try {  
        connect = new URL(urlStr);  
        HttpURLConnection connection = (HttpURLConnection)connect.openConnection();  
        connection.setRequestMethod("POST");  
        connection.setDoOutput(true); 
        connection.setDoInput(true);
        connection.setUseCaches(false);//post不能使用缓存
        connection.setInstanceFollowRedirects(true);
        connection.setRequestProperty("accept", "*/*");
        connection.setRequestProperty("connection", "Keep-Alive");
        connection.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
        OutputStreamWriter paramout = new OutputStreamWriter(  connection.getOutputStream(),"UTF-8"); 
        String paramsStr = "";   //拼接Post 请求的参数
        for(String param : params.keySet()){
           paramsStr += "&" + param + "=" + params.get(param);
        }  
        if(!paramsStr.isEmpty()){
            paramsStr = paramsStr.substring(1);
        }
        paramout.write(paramsStr);  
        paramout.flush();  
        BufferedReader reader = new BufferedReader(new InputStreamReader(  
                    connection.getInputStream(), "UTF-8"));  
        String line;              
        while ((line = reader.readLine()) != null) {          
            data.append(line);            
        }   
        paramout.close();  
            reader.close();  
        } catch (Exception e) {  
            // TODO Auto-generated catch block  
            e.printStackTrace();  
        }  
       return data.toString();
}

@Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**")
                .allowedOrigins("*")  
                .allowedMethods("GET", "HEAD", "POST", "PUT", "DELETE", "OPTIONS")
                .allowCredentials(true)
                .maxAge(3600)
                .allowedHeaders("*");  
    }

private CorsConfiguration corsConfig() {
    CorsConfiguration corsConfiguration = new CorsConfiguration();
    * 请求常用的三种配置，*代表允许所有，当时你也可以自定义属性（比如header只能带什么，只能是post方式等等）
    */
    corsConfiguration.addAllowedOrigin("*");
    corsConfiguration.addAllowedHeader("*");
    corsConfiguration.addAllowedMethod("*");
    corsConfiguration.setAllowCredentials(true);
    corsConfiguration.setMaxAge(3600L);
    return corsConfiguration;
}
@Bean
public CorsFilter corsFilter() {
    UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
    source.registerCorsConfiguration("/**", corsConfig());
    return new CorsFilter(source);
}