The callback address parameter in the OAuth authorization link is missing

There is a callback address parameter in the OAuth authorization link:

https://developers.e.qq.com/oauth/authorize?client_id=123456&redirect_uri=https://www.baidu.com?platform=jiaobuchong&name=jack&state=&scope=ADS_MANAGEMENT

The callback address parameter in this authorization link is:

https://www.baidu.com?platform=jiaobuchong&name=jack

After authorization, the address becomes:

https://www.baidu.com?platform=jiaobuchong&auth_code=xxxxxxx

The parameter name=jack is missing. The solution is to platform=jiaobuchong&auth_code=xxxxxxxperform URLEncoder on the query parameter in the callback address . Such as:

public class UrlencoderDemo {
    
    

    public static void main(String[] args) throws Exception {
    
    
        String url = "https://www.baidu.com?platform=jiaobuchong&name=jack";
        System.out.println(getEncodeQueryUrl(url));
        System.out.println(getEncodeQueryUrl("https://www.baidu.com?"));
        System.out.println(getEncodeQueryUrl("https://www.baidu.com"));
        System.out.println(getEncodeQueryUrl("https://www.baidu.com/"));

    }

    public static String getEncodeQueryUrl(String url) throws UnsupportedEncodingException {
    
    

        if (StringUtils.isBlank(url)) {
    
    
            throw new IllegalArgumentException("url is blank");
        }
        int pos = url.lastIndexOf("?");
        if (pos > -1 && (pos < (url.length() - 1))) {
    
    
            return url.substring(0, pos + 1) + URLEncoder.encode(url.substring(pos + 1), "UTF-8");
        }

        return url;
    }
}

Output:

https://www.baidu.com?platform%3Djiaobuchong%26name%3Djack
https://www.baidu.com?
https://www.baidu.com
https://www.baidu.com/

The authorization link becomes ok like this:

https://developers.e.qq.com/oauth/authorize?client_id=123456&redirect_uri=https://www.baidu.com?platform%3Djiaobuchong%26name%3Djack&state=&scope=ADS_MANAGEMENT

Reference: When
WeChat authorization callback, the original parameters in the callback address are missing.
WeChat development-authorization interface URL multi-parameter request problem
. Special characters escape encoding in URL URL