Question

我想发送 {＆＃34;名称＆＃34;：＆＃34;超级用户＆＃34;，＆＃34;状态＆＃34;：1} 但是当我发送i时得到这个错误

Exception in thread "main" java.lang.NullPointerException
    at java.io.Reader.<init>(Reader.java:78)
    at java.io.InputStreamReader.<init>(InputStreamReader.java:72)
    at com.service.RoleService.updateRole(RoleService.java:145)
    at com.service.RoleService.main(RoleService.java:176)

这是代码

URL url = new URL("http://localhost:31109/user/role/"+role_id);
        HttpURLConnection httpConnection = (HttpURLConnection) url.openConnection();
        httpConnection.setDoOutput(true);
        httpConnection.setRequestMethod("PUT");
        httpConnection.setRequestProperty("Content-Type", "application/json");
        httpConnection.setConnectTimeout(15000);

        String input = "{\"name\":\""+name+"\",\"status\":"+status+"}";
        System.out.println(input);


        OutputStream outputStream = httpConnection.getOutputStream();

        outputStream.write(input.getBytes());

        outputStream.flush();

        if(httpConnection.getResponseCode() !=200){
            String error_resp;
           BufferedReader error_responseBuffer = new BufferedReader(new InputStreamReader(
                (httpConnection.getErrorStream()))); 
           while((error_resp = error_responseBuffer.readLine()) != null){
               System.out.println("Error responsecode => "+httpConnection.getResponseCode()+"error => "+error_resp);
               output = new JSONObject(error_resp);
           }
        }else {
            BufferedReader responseBuffer = new BufferedReader(new InputStreamReader(
                    (httpConnection.getInputStream())));
            String httpresponse;
            StringBuilder content = new StringBuilder();
            while((httpresponse = responseBuffer.readLine()) != null){
                content.append(httpresponse);
            }
             output = new JSONObject(content.toString());
        }
        httpConnection.disconnect();

然而，当我发送 {＆＃34;名称＆＃34;：＆＃34;超级用户＆＃34;，＆＃34;状态＆＃34;：＆＃34; 1＆＃34;} 请求没问题，但API有一个验证，要求将其作为整数发送并拒绝它。我无法改变api。

Answer 1

您正在尝试为URL调用的响应创建一个Reader，但套接字可能已经关闭。您应检查httpConnection.getXXXStream调用以确保httpConnection仍处于活动状态，并且getStream调用的返回值不为null。

- 编辑 -

您对responseCode != 200的检查是个问题。 100s和200s中的响应代码都不是错误，并且不会使用错误流。否则，您应该检查您从httpConnection获取的输入流，例如

    if(httpConnection.getResponseCode() !=200){
        String error_resp;
        InputStream in = httpConnection.getErrorStream();
        if (in == null) return; // check if the error stream is null
       BufferedReader error_responseBuffer = new BufferedReader(new InputStreamReader(
            (httpConnection.getErrorStream()))); 
       while((error_resp = error_responseBuffer.readLine()) != null){
           System.out.println("Error responsecode => "+httpConnection.getResponseCode()+"error => "+error_resp);
           output = new JSONObject(error_resp);
       }
    }else {
        InputStream in = httpConnection.getInputStream();
        if (in == null) return; // check inputstream
        BufferedReader responseBuffer = new BufferedReader(new InputStreamReader(
                (in)));
        String httpresponse;
        StringBuilder content = new StringBuilder();
        while((httpresponse = responseBuffer.readLine()) != null){
            content.append(httpresponse);
        }
         output = new JSONObject(content.toString());
    }
    httpConnection.disconnect();

在java中的http PUT请求中发送一个整数

1 个答案: