Question

我使用过XMLHttpRequest和Promise。我将在pormise回调函数（then（））中设置其他标头，该标头未设置为请求并且面对“对象的状态必须打开”。但是我已经在设置请求之前打开了。请找到代码段供您参考。

DOMException: Failed to execute 'setRequestHeader' on 'XMLHttpRequest': The object's state must be OPENED.

 <div class="html5_upload">
        <input type="file" id="upload" class="uploadBtn" name="UploadFiles" />

        <button class="uploadBtn" onclick="uploadFiles()">Upload File</button>
    </div>

    <script>

    function uploadFiles() {
        var xhr = new XMLHttpRequest();
        var file = document.getElementById('upload').files[0];
        var formData = new FormData();

        formData.append('UploadFiles', file); 
        xhr.open('POST', 'https://localhost:44310/api/values/save', true);

        new Promise(function (resolve, reject) {
            resolve();
        }).then(function () { 
            xhr.setRequestHeader('custom', 'new');
        });
        xhr.onerror = function (args) {
            console.log('error occurs..!');
        }
        xhr.send(formData); 
    }
    </script>

Answer 1

我认为您的@Bean public RestTemplate restTemplate() { HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory(); RestTemplate restTemplate = new RestTemplate(requestFactory); List<HttpMessageConverter<?>> converters = new ArrayList<>(); StringHttpMessageConverter stringConverter = new StringHttpMessageConverter(); stringConverter.setWriteAcceptCharset(false); converters.add(stringConverter); restTemplate.setMessageConverters(converters); restTemplate.getMessageConverters().add(new ByteArrayHttpMessageConverter()); restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter()); return new RestTemplate(requestFactory); }应该在xhr.send(formData)内部。您可以尝试下面的代码，看看它是否按预期工作。

.then()

在promise调用中设置请求标头时，标头未设置为服务器

1 个答案: