Http Post Request在Java 7和Java 7之间提供了不一致的结果。 Java 8用于完全相同的代码

Question

下面是使用Java 7编译和执行的代码段，其结果与Java 8的结果不同。

在进入Native之前尝试使用apache httpclient。我假设与其他库的问题是相同的

输出Jdk7

{"error":"invalid_grant","error_description":"authentication failure"}    java.io.IOException: Server returned HTTP response code: 400 for URL: XXX           at ``sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1627)

输出Jdk8：预期结果

public String requestSFAuthToken(Map<String, String> sfAttributes) throws Exception{
    StringBuilder result = new StringBuilder();        
    String request = sfAttributes.get("url");
    URL url = new URL(request);
    HttpURLConnection conn = (HttpURLConnection) url.openConnection();
    OutputStreamWriter writer  = null;
    BufferedReader reader = null;
    try{

    conn.setRequestMethod("POST");
    conn.setRequestProperty( "Content-Type", "application/x-www-form-urlencoded");
    conn.setRequestProperty( "Accept", "application/json"); 
    conn.setDoOutput(true);
    conn.setAllowUserInteraction(true);
    conn.connect();
    writer = new OutputStreamWriter(conn.getOutputStream());
    writer.write(getParameters(sfAttributes));
    writer.flush();
    String line;
    reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
    while ((line = reader.readLine()) != null) {
        System.out.println(line);
        result.append(line);
    }
    writer.close();
    reader.close(); 
    conn.disconnect();
    }catch(Exception e){
        if(conn != null){
            String error ; 
            reader = new BufferedReader(new InputStreamReader(conn.getErrorStream()));
            while ((error = reader.readLine()) != null) {
                System.out.println(error);
            }
        }
        throw e;
    }finally{
        if(conn != null){
            conn.disconnect();
        }
        if(writer != null){
            writer.close();
        }
        if(reader != null){
            reader.close(); 
        }
    }

    return result.toString();
}

private String getParameters(Map<String, String> sfAttributes) throws UnsupportedEncodingException {
    String params = URLEncoder.encode("grant_type", "UTF8")
            + "="+ URLEncoder.encode(sfAttributes.get("grant_type"), "UTF8");
    params += "&"+ URLEncoder.encode("client_id","UTF8")
            + "="+ URLEncoder.encode(sfAttributes.get("client_id"), "UTF8");
    params += "&"+ URLEncoder.encode("client_secret", "UTF8")
            + "="+ URLEncoder.encode(sfAttributes.get("client_secret"), "UTF8");
    params += "&"+ URLEncoder.encode("username", "UTF8")
            + "="+ URLEncoder.encode(sfAttributes.get("username"), "UTF8");
    params += "&"+ URLEncoder.encode("password", "UTF8")
            + "="+ URLEncoder.encode(sfAttributes.get("password"), "UTF8");
    return params;
}