ajax发送请求跨域

问题：ajax发送请求出现cors跨域

解决办法：可以通过java代理的方式，后台发送请求

1.get请求

public void proxyGet(String url) {
   try {
      URL realUrl = new URL(url);
      URLConnection connection = realUrl.openConnection();
      // 设置通用的请求属性
      connection.setRequestProperty("accept", "*/*");
      connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded;charset=UTF-8");
      connection.setRequestProperty("Connection", "Keep-Alive");

      // 建立实际的连接
      connection.connect();
      InputStream inStream = connection.getInputStream();
      OutputStream stream = response.getOutputStream();
      stream.write(GetInputStream(inStream));  //上传参数
      stream.flush();
      stream.close();
   } catch (Exception e) {
      e.printStackTrace();
   }
}

2.post请求

public String proxyPost(String url, String params) {
    String result = null;
    CloseableHttpClient httpclient = HttpClientBuilder.create().build();
    HttpPost httpPost = null;
    CloseableHttpResponse response = null;
    try {
        httpPost = new HttpPost(url);
        // 设置通用的请求属性
        httpPost.setHeader("Accept", "application/json");
        httpPost.setHeader("Content-Type", "application/json;charset=UTF-8");
        // 往服务器里面发送数据
        StringEntity entity = new StringEntity(params, StandardCharsets.UTF_8);
        httpPost.setEntity(entity);
        // 建立实际的连接
        response = httpclient.execute(httpPost);
        StatusLine status = response.getStatusLine();
        System.out.println("请求返回状态："+status.getStatusCode());
        // 获取返回数据
        if (status.getStatusCode() == 200) {
            HttpEntity responseEntity = response.getEntity();
            result= EntityUtils.toString(responseEntity);
        }
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        if (response != null) {
            try {
                response.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        try {
            httpclient.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    return result;
}